Presentation on theme: "SURFACE FINISHINGS The art of treating the surface of building materials with a suitable covering material to make them weather resisting and decorative."— Presentation transcript:
1 SURFACE FINISHINGSThe art of treating the surface of building materials with a suitable covering material to make them weather resisting and decorative is called surface finishing.The covering material used for surface finishings are called surface finishes which are plasters, paints, washes etc.
2 PURPOSETo protect the surface from the effects of weathering agencies.To provide a smooth surface.To provide pleasing appearance to the surface.
3 IMPORTANT TECHNICAL TERMS Background :- The surface to which first coat of plastering is applied is called background.Dubbing out:- The filling the hollow spaces of the back ground before applying the plaster is called dubbing out.Finishing coat:- The final layer of the surface finish is called finishing coat.Hacking:- The process of making the background rough to act as key for plastering is called hacking.
4 Important Technical Terms (-ctd-) Gauging:- The mixing of various constituents of plaster is called gauging.Rendering coat:- The first coat of plastering is called rendering coat.Under coat:- The layer providing base for the application of remaining coats is called under coat.Floating:- The process of providing a finishing coat with a float is called floating.
5 Important Technical Terms (-ctd-) Peeling:- The removal of the plaster from the background is called peeling.Blistering:-The local swelling of a finished plastered or painted face is known as blistering. This is due to lack of adhesion of the plaster or paint with the surface.Cracking:-The development of angular fractures or cracks in a plastered surface is called cracking. In case of painting it indicates the presence of a soft under coat.Checking:-The longitudinal split in a painted or plastered surface is known as checking.
6 Important Technical Terms (-ctd-) Chalking:-The dull and powdery appearance of a painted or plastered surface is known as chalking. It indicates insufficient or inferior binding material used in the paint or plaster.Crazing:-The irregular development of hair like cracks on a plastered surface is termed as crazing.Dado:-The special treatment provided to plastered walls at their lower level usually in bathrooms is called dado. It is provided up to one meter height from the floor level. It may be consisting of rich cement mortar, glazed tiles etc.
7 Important Technical Terms (-ctd-) Skirting:- The special treatment provided to plastered walls at their lower level usually in drawing and living rooms of a building is called skirting.It is provided up to 15cm height from the floor level.It is usually consisting of the material which is used for providing margin or boarder of flooring.It is provided to protect the walls from water in case of washing of floors
8 PLASTERINGThe art of covering the surface of masonry work with a suitable material is called plastering.
9 PLASTERINGA fine paste of mortar made by mixing cement with sand or fat lime with sand or surkhi in addition to sufficient quantity of water if called plaster.When cement is used as a binding material, the plaster is called cement plaster and if lime is used as the binding material, it is called lime plaster.An ideal plaster should be smooth, non absorbent and washable. It should not be affected by weathering agencies.
10 PLASTERINGThe finished surface of walls constructed in bricks or stones are generally so coarse textured that they provide unsuitable finish for the internal walls of most of the buildings.These surfaces are rendered smooth by the application of one or two coats of plaster. The ceilings are also rendered smooth with plaster.
11 PLASTERINGThe object of external plastering is to cover the surface to enable it to resist the effect of weathering agencies. However, a good brick work made of sound, well burnt bricks or neat stone masonry constructed of durable stones does not require external plastering.The object of internal plastering is to provide a smooth surface in which dust and dirt cannot lodge and to form a smooth surface for applying white or color wash, distemper or paint.
12 TYPES OF PLASTERING 1. CEMENT PLASTERING The mix ratio of mortar in case of cement plastering depends upon the nature of the work to be plastered.For rich plastering work at sensitive places (e.g. in side bathrooms, W.C. etc.), 1:3 cement plaster mix is used. For general plastering of walls 1:5 to 1:8 cement plaster mixes are used.
13 CEMENT PLASTERING (-ctd-) Preparing the surfaceBefore applying the plaster, the surface should be prepared properly.The joint of masonry are properly raked to a depth of 10 to 15 mm to provide key to plaster.The surface is then thoroughly wetted with water, washed well and kept wet for six hours.When the surface is ready, plaster is applied.
14 CEMENT PLASTERING (-ctd-) Applying the plasterCement plastering may be applied in one ortwo coats.In case of plastering of single coat, the mortar is dashed against the prepared surface into a uniform thickness with the help of trowel.Wooden screeds 7.5 cm wide and of required thickness of the plasters are generally fixed vertically 2.4 to 3 m apart to act as gauges guides in order to keep the plaster to the required thickness. Careful plumbing should be done in fixing of these screeds.
15 CEMENT PLASTERING (-ctd-) Surplus mortar is removed with the help of mason’s straight edge and then the mortar is pressed well with a wooden float so that mortar may fill in the joints of the masonry.The surface is then finally polished with a trowel or iron float.The thickness of this coat should not be more than 16 mm.
16 CEMENT PLASTERING (-ctd-) In case plastering is to be done in two coats the first coat is applied as described above with the only difference that it is not polished.Before applying the second coat, the first coat is allowed to set but it would not become dry and it is also roughened with a scratching tool to provide key to the second coat.The second coat is then applied in a thin layer not exceeding 3 mm in thickness within 48 hours.It is then well trowelled and rubbed perfectly smooth with the help of a steel float. It is then allowed to set for 2 days and cured for more than 7 days.
17 CEMENT PLASTERING (-ctd-) SuitabilityThis type of plastering forms an ideal coating for external finishings.It is also used for internal renderings of common as well as important buildings.It is specially suited for damp conditions i.e. bathrooms, etc.
18 2. LIME PLASTERINGThe proportioning of the ingredients of a lime plaster is adopted according to the number of coats to be applied.If the plaster is to be applied in one coat, 1 part of lime to 1.5 parts of sand is used.If two coats are to be applied, the proportion for the first coat is same as above while the second coat consists of two parts of lime and one part of sand.
19 LIME PLASTERING (-ctd-) If three coats are to be applied, the proportion of the third coat consists of 4 parts of lime to one part of sand.In actual practice, all the coats consist of 1 part of lime to 2 part of sand.Thickness of the lime plaster varies from 15mm to 20mm.
20 LIME PLASTERING (-ctd-) Preparing the surfaceThe method of preparing the surface is same as described in case of cement plastering.
21 LIME PLASTERING (-ctd-) Application of first coatIt is applied by dashing the lime plaster with the help of trowel against the wall surface between the screeds.Plaster is pressed well in the joints.Function of this coat is to fill all the irregularities of the surface.Average thickness of this coat is 10 to 12 mm. It is then left to dry for 3 to 4 days.
22 LIME PLASTERING (-ctd-) Application of second coatBefore applying this coat, the first coat is well washed and scratched over with the edge of a trowel.The second coat is then pressed against the wall with mason’s trowel and rubbed with a straight edge.Thickness of this coat is 6 to 10 mm.
23 LIME PLASTERING (-ctd-) Application of final and finishing coatThis coat usually consists of fat lime which is called lime putty.It is applied on the second coat, made perfectly plain and then rubbed first with wooden float and then with a steel float to polish the surface,It is about 3 to 6 mm in thickness.It is allowed to dry for two days and then the surface is cured for 7 to 10 days.
24 LIME PLASTERING (-ctd-) SuitabilityThis type of plastering is suitable for internal renderings of buildings. But it is not commonly adopted these days.
25 3. MUD PLASTERINGThe wall surface is first prepared as described in case of cement plastering.The mud plaster is then evenly dashed against the wall surface with a wooden float.After 24 hours, the surface is tamped. The function of tamping is to compact the layer and to drive it deep into the joints. It also helps to avoid developments of cracks due to hollows.
26 MUD PLASTERING (-ctd-) After tamping, water is sprinkled slightly and the surface is polished with a steel trowel.A thin wash of cow dung is then given and tamping is done again at the places where small cracks have formed.Finally the surface is given a wash of fine white earth and cow-dung.Sometimes, surface is given a wash of fine earth, cow dung and cement in proportion of 3 : 2 : 1.
27 MUD PLASTERING (-ctd-) SuitabilityThis type of plastering is done on walls oftemporary sheds and country side buildings.
28 4. STUCCO PLASTERING This is special type of plaster. Stucco is the name given to a decorative type of plaster which provides an excellent finish like that with marble lining.After preparing the surface, stucco plastering is applied in three coats.Each coat should be permitted to dry thoroughly before applying the next coat.
29 STUCCO PLASTERING (-ctd-) For internal surface, the first coat also known as scratch coat consists of lime plaster 12 mm in thickness.The second coat or brown coat consists of rich lime plastering in 10 mm thickness.The final coat or finishing coat consists of a mixture of very fine lime and white ground stone ( marble or quartz), 3 mm in thickness.It is carefully polished with a bag of linen containing moist chalk in the first instance and then chalk and oil.The surface is then finally finished by rubbing it with only oil as to make it smooth and bright.
30 STUCCO PLASTERING (-ctd-) For external surfaces, the first and second coats are 10 to12 mm thick and the finishing coat is 3 to 6 mm thick.The proportion of ingredients for the first two coats is 1 part of cement to 3 parts of sand with 10% by weight of hydrated lime.The finishing coat consists of 1 part of cement and 2 pars of sand in which some coloring pigment is added or colored cement is used.
31 STUCCO PLASTERING (-ctd-) Method of applying this plaster is same as described in case of cement or lime plastering.SuitabilityThis type of plastering is suitable for external as well as internal surfaces of buildings to provide an excellent finish.
32 5. MOUGHAL PLASTERINGIt is generally applied in two coats of lime mortar by mixing lime, sand and surkhi in the ratio of 4:3:1 along with glue and powdered gull nut.The surface is well wetted and the second coat of about 1.25 mm thickness is applied when the first coat is hardened.The finished plastered surface is kept wet for 3 weeks.
33 MOUGHAL PLASTERING (-ctd-) SuitabilityThis type of plastering is suitable for internal surfaces of high class buildings but it is not commonly applied these days.
34 POINTINGFinal treatment with cement or lime mortar made to the joints of the masonry to provide neat appearance is termed as pointing.The joint on the face of stone or brick masonry are roughly filled in while the walls are being raised.They are after wards neatly finished off to make them water tight.The joints thus finished, give a better appearance to surface and prevent rain water from entering the interior of the masonry.
35 PURPOSETo prevent the moisture and the rain water from entering the interior of masonry through joints and to make them durable.To improve the appearance of the structure.
36 SUITABILITYPointing is preferred to plastering under following conditions.1. When a smooth and even surface is not essentially required.2. Where it is desirable to exhibit to view the natural beauty of the materials (bricks or stones) used in construction.3. When the workmen ship is neat and good.
37 TYPES OF POINTINGThe selection of particular type of pointing depends upon the types of bricks or stone used and the appearance required..
38 TYPES OF POINTING (-ctd-) 1. Flat or flush pointingIn this pointing, the mortar is pressed tightly and the joints are filled up and made flush with the face of the wall.This is the simplest type of pointing and is provided extensively.It is economical and durable because it requires less labor than all other pointing.It does not afford a lodging place for dust.
39 TYPES OF POINTING (-ctd-) 2. Struck pointingIn this pointing the face of the mortar joint instead of keeping it vertical, its upper side is kept about 12 mm inside the face of the masonry and the bottom is kept flush with the face of the wall as shown in fig 14.2.This pointing has a better effect of throwing rain water.This is also known as ruled pointing.This pointing is the best in ordinary circumstances.
41 TYPES OF POINTING (-ctd-) 3. Recessed pointingIn this pointing the face of the mortar joint is pressed inside by means of a suitable tool and is left vertical instead of being made inclined.This pointing is provided when face work of good textured bricks with good quality mortar is used.
42 TYPES OF POINTING (-ctd-) 4. V-pointingThis type of pointing is provided by forming a v-shaped groove inside the mortar of the joint with a special tool (steel or iron jointer).This pointing is commonly recommended for brick work in case of governmental buildings.
44 TYPES OF POINTING (-ctd-) 5. Weather pointingThis is similar to V-Pointing but in this case instead of pressing a v shaped groove inside, it is provided by forming a v shaped projection outside the wall’s surface.This pointing is generally recommended for superior brick work.
45 TYPES OF POINTING (-ctd-) 6. Keyed or grooved pointingIn this case, the joints are first filled up flush, and then a circular piece of steel or iron is pressed in and rubbed in the middle of joints.Grooved pointing has a big groove in the face than keyed.Keyed pointing gives an attractive appearance to the structure and is generally used for superior work.
48 TYPES OF POINTING (-ctd-) 7. Tuck pointingIn this pointing, the mortar joints are filled with the face of the wall. Then 6 mm wide and 3 mm deep groove is immediately and carefully formed in the centre of the joint and the groove is filled with or tucked in with white lime putty.The lime putty is given a maximum projection of 6 mm.Tuck pointing has a neat attractive appearance. But the lime putty is not durable and in due course of time becomes defective.
49 JOINTS IN BUILDINGSThe separations or planes of weakness introduced at different locations in a building are known as joints in the buildings.When joints are provided in a building, reasonable care has to be exercised for the location, design, detailing of joints and selecting materials for forming and filling the joints.
50 JOINTS IN BUILDINGSAll building materials expand or contract with change in temperature and variation in moisture contents. Thus, major dimensional changes are caused in structures due to expansion or contraction of materials used in their construction.The magnitude of these changes varies with the type of material used.To overcome this problem, the large and multi-storied buildings may either be constructed monolithically with heavy reinforcement to link each of their component parts or they may be provided with a number of jointsJoints are usually provided in large or multistoried buildings. But joints should not be provided in shell structures and certain other rigid structures where provision of joints interferes with the rigidity of structure.
51 TYPES OF JOINTS 1- CONTRACTION JOINTS The joints introduced in concrete structures to localize shrinkage movements are known as contraction joints.The contraction joints are in the form of separations or planes of weakness.The function of these joints is to localize shrinkage movements which would otherwise lead unsightly cracks.
52 TYPES OF JOINTS (-ctd-) Contraction joints may be of any of the following types:-(a) Complete contraction jointIn this type of contraction joint, the bond between the adjacent sections of a structure may be broken completely by painting one face with a bituminous material or by setting a layer of waterproof paper or roofing felt against the face of the section before casting the next adjacent section.These contraction joints are provided in thick sections of concrete to localize shrinkage movements.
53 TYPES OF JOINTS (-ctd-) (b) Partial contraction jointIn this type of contraction joint, the reinforcement is continued across the joint. Due to presence of reinforcement, the movement at such joints is usually very small.These contraction joints are provided in concrete sections where structural stability is also required in addition to localize shrinkage movements.
54 TYPES OF JOINTS (-ctd-) (c) Dump jointsIn this type of contraction joint, a plane of weakness is created by forming a groove in either or each of the surface of concrete structure.The total depth of such a groove is one-third to one-fifth of the thickness of the concrete section.These contraction joints are used more particularly in thin sections of concrete such as floor slabs, roof slabs etc.
55 TYPES OF JOINTS (-ctd-) 2- SLIDING JOINTSThe joints provided between the two parts enabling their movement freely in both the planes are known as sliding joints.These joints are usually formed by applying a layer of plaster to one of the surfaces and finishing it smooth so as to act as seat of the sliding joint.The seat is then allowed to be hardened and covered with the required thickness of bituminous materials or otherwise treated as specified to form a slip plane before the other portion is cast on it.
56 TYPES OF JOINTS (-ctd-) SLIDING JOINTS (-ctd-)The function of these joints is to enable freedom of movement of the two parts in both the planes.These joints are used when variations in temperature, moisture contents or loading result in tendency for one part to move in a plane at right angles to the plane of another part of a structure.
57 TYPES OF JOINTS (-ctd-) 3- CONSTRUCTION JOINTSThe joints provided at locations where construction stops for any reason and when their location does not coincide with that of expansion or contraction joints are called construction joints.These joints are constructed in a similar manner as contraction joints but these joints are not intended to accommodate movement due to contraction.Every effort should be made to prevent movement occurring at such joints.However, extra care may be taken to obtain a good bond between abutting sections of concrete.
58 TYPES OF JOINTS (-ctd-) CONSTRUCTION JOINTS (-ctd-)Since, cracks frequently develop at these joints as a result of stresses arising from variations in temperature, moisture content or loading, therefore, it is most desirable that construction joints should coincide with expansion or contraction joints wherever possible.The function of these joints is to simplify the construction of a structure.Construction joints in floor should be located in the middle of spans of slabs, beams or girders unless a beam intersects the girder at this point in which case the joints in the girders are provided at a distance equal to twice the width of beam.Adequate provision should be made for shear by use of inclined reinforcement.Joints in column should be made at the underside of the floor.
59 TYPES OF JOINTS (-ctd-) 4- EXPANSION JOINTSThe joints provided to accommodate the expansion of adjacent parts in a building are known as expansion joints.These joints essentially consist of a space between the adjacent parts of a structure and may sometimes be provided with the load transmitting devices between the parts.They are generally filled with expansion joint filler of approved quality.
60 TYPES OF JOINTS (-ctd-) EXPANSION JOINTS (-ctd-)The function of these joints is to accommodate the expansion of adjacent parts of a building and relieve the compressive stresses that may otherwise develop.These joints are provided in long masonry walls, roofs and floors, roof or floor to wall joints, framed structures etc. For spacing of these joints in different locations, refer to table
61 TYPES OF JOINTS (-ctd-) EXPANSION JOINTS(-ctd-)The design and location of joints usually depend upon the type of structure, the method of construction and the jointing materials available.The provisions of joints should be adequate to accommodate all the dimensional changes caused by expansion and contraction of materials used in the structure.
62 TYPES OF JOINTS (-ctd-) EXPANSION JOINTS (-ctd-)In case of masonry walls, the vertical control joints (expansion joints) should be provided from top of the wall to the top of the concrete foundations and not through the foundation concrete. The reinforcement should not pass through such joints.In case of masonry walls resting on pile foundation, the vertical control joints should be taken up to the top of grade beam i.e. concrete cap over the piles without making use of any reinforcement passing through the joints.In case of reinforced framed structures, the vertical control joint between any two columns should extend from top of the column to the top of the pedestal provided over the RCC footing.
63 Spacing of Expansion Joints S. No.Item and DescriptionSpacing of Expansion Joints12Walls:Load bearing walls with cross walls at intervals. Traditional type of one-brick thick or more.Walls warehouse type construction (without cross-walls)Chajjas, balconies and parapets.30 m intervals.Expansion joints in walls at 30 m maximum intervals. (If the walls are panel walls between columns at not more than 9 m centers, no joints are necessary). Control joints over centre of openings may be provided at half the spacing of expansion joints.6 to 12 m intervals.
64 Spacing of Expansion Joints S. No.Item and DescriptionSpacing of Expansion Joints345Roofs :Ordinary roof slabs of RCC protected by layers of mud phuska or other insulating media in framed construction.Thin unprotected slabs.Frames :Joints in structure through slabs, beams, columns etc, dividing the building into two independent structural units.Coping20 to 30 m intervals and at changes in direction as in L, T, H and V shaped structures.15 m intervals.Corners of L, T, H and V shaped structures at 30 m intervals in long uniform structures.Corresponding to joints in the roof slabs.
65 DOORSThe arrangements made to provide free and easy access inside and outside the rooms of a building are called Doors. Whereas, the opening provided in the boundary wall of a building for entrance and exist is known as Gate.
66 DOORS (-ctd-)Doors are generally made of timber. They may also be consisting of plywood, wire gauge, frame work of steel etc.They may be having one or two leaves or shutters.The doors with one shutter are known as single leafed doors. Such doors are used for small openings.The doors having double leaves or shutters are called double leafed doors. Such doors are used for large openings.
67 LOCATION OF DOORSDoors should be located in such a way that free movement in and out of the rooms of a building is ensured. Doors should be properly placed in the corner of a room.In case the room is to be provided with more than one door, they should be located in the opposite walls to have a good ventilation in that room.
69 IMPORTANT TECHNICAL TERMS Frame:- An enclosure to provide support for door or window shutter is called frame. It is made from the well seasoned wood. Head and sill are morticed to take the tenon formed at the ends of vertical posts. Bamboo pins are used to hold shoulders and the tenons tightly.Head:-The top horizontal member of a door or window frame is called head.Sill:- The bottom horizontal member of a door or window frame is called sill.Posts:- The vertical side members of a door or window frame are called posts.
70 IMPORTANT TECHNICAL TERMS (-ctd-) Shutters:- The planks, framed, paneled or otherwise which fit in a door or window frame are known as shutters. They are hung to the frame by means of hinges.Styles or stiles:- The vertical side members of frame-work of a shutter are called styles. The style which is hung or hinged to the frame is called a hanging or hinged style. Whereas the style which is not hung or hinged to the frame is called a meeting style.Top rail:- The topmost horizontal member of the frame-work of a shutter is known as top rail.Lock rail:- The middle horizontal member of the frame-work of a shutter where lock sliding bolt is fixed is called lock rail.
71 IMPORTANT TECHNICAL TERMS (-ctd-) Bottom rail:- The lower most horizontal piece or member of the frame-work of a shutter is known as bottom rail.Mullion:- The vertical member running through the middle of frame-work of a shutter is called mullion or muntin.Jambs:- The vertical faces of a door or window opening which support the frame of a door or window are called jambs.Reveal:- The portions of a door or window opening extending beyond the frame towards the face of a wall are called reveals.Sash bars:- The light members of the frame-work which carry the glass panes within a shutter or frame work are known as sash bars.
72 IMPORTANT TECHNICAL TERMS (-ctd-) Panels:- The small wooden members which are provided between the rails of a shutter or frame-work are called Panels.Rebate:- Depression or cut in the frame of a door or window to receive the shutters is called rebate.Horns:- The projections of head or sill of a door or window frame are known as Horns. These are generally embedded in the masonry to increase their fixing strength.Louver:- The inclined boards fixed in a frame-work are called Louvers.
73 IMPORTANT TECHNICAL TERMS (-ctd-) Transom:- The horizontal dividing member in a window or door frame provided with fan light is called Transom. It acts a head of the door or window frame and sill of the fan light.Stops:- The timber pieces fixed to the door or window frame on inside to prevent the shutters from damaging the plaster of jambs when fully opened are called stops.Chocks:- The timber pieces hinged to the window or door frame on outside to prevent the shutters from closing under the effect of heavy wind are called chocks.
74 FIXING OF A DOOR FRAME IN A WALL A door frame is fixed in the masonry by hold fasts built into the walls with cement mortar (1: 5).The hold fasts are made from 3.7 cm x 0.6 cm flat, bent at both ends One end of each hold fast is fixed on the side of the door frame and its other end is built into the masonry.The horns provided at the head and sill or in between, are also built into the walls.Now-a-days, sill is not provided in case of a door frame since it causes obstruction to the free movement and does not permit easy cleaning and washing of floors.Before fixing a door frame, its sides coming in contact with masonry, are painted with two coats of a wooden-preservative (generally coal tar). The other sides of the frame are generally given a priming coat.
76 1. Ledged and battened doors These are the simplest type of doors.They consist of battens (each 15 cm wide and 0.8 to 1.8 cm thick) which are screwed to three horizontal members called ledges.Top ledge is 10 cm x 3.2 cm in cross-section, middle and bottom ledges have section of 17.5 to 20 cm x 3.2 cm.Battens are generally tongued and grooved.These doors are mostly used for narrow openings in temporary houses where appearance is not the main consideration.
77 1- Ledged and Battened Ledged 2- Battened and Braced Door
78 2. Ledged, battened and braced doors This type of door is similar to a ledged and battened door except that they consist of ledges and battens which are strengthened with the help of diagonal members known as braces.The width of braces varies from 10 to 15 cm and thickness is 3.2 cm.The inclination of the braces should be kept towards the side of the shutter to be hinged to the frame as shown in figThese doors can be used for comparatively large openings in ordinary houses and in places where appearance is not so important.
79 3. Framed, ledged, battened and braced doors This is a better and strong type of door.They consist of two stiles, three rails and two braces forming the frame-work of each leaf (shutter) to which he battens are fixed.The frame-work is made with mortice and tenon joints.The top and bottom rails and the stiles have full thickness while the middle (lock) rail and braces are thinner in section to allow the battens to pass over them and finish flush with the top and bottom rails.The battens should butt into the rebate in the top and bottom rails.These shutters are hung to the frame by means of butt hinges.These doors are mostly used as external doors in ordinary residential buildings, shops etc.
80 3- Framed, Ledged, Battened 4- Framed and Paneled Door and Braced Door
81 4. Framed and paneled doors This is the most common type of door.They are made in different designs but their principle for construction is same as in other doors.They consist of frame-work of styles, rails and muntins or mullions of same thickness.The space between them is filed with panels. The vertical styles are continuous from top to bottom and rails are jointed to the styles.On inside of the styles and rails, grooves are made to receive the panels which may be of raised or flush type.These shutters are hung to the frame by means of butt hinges.These doors are mostly used in residential and other buildings as internal and external doors.
82 5. Paneled and glazed doors The construction of this type of door is similar to a framed and paneled door but in such doors glass panes are fixed.In these doors, instead of wooden panels in their top portions, sash bars to receive the glass panes are used.Sash bars are equal in thickness to the full thickness of the shutter, with 2.5 cm with and having 1 to 3 cm rebate according to the size of the doors.The size of the rebate is generally 1.6 cm x 0.6 cm. Each glass pane is secured in position by small nails and is bedded with the help of lime-putty.It may be either 1/3rd glazed at top and2/3 paneled at bottom, or 2/3 glazed at top or 1/3 panelled at bottom.These doors are mostly used in public buildings, hospitals, colleges, offices and also in residential buildings.
84 6. Flush doorsThese doors are made with plywood and give better appearance.They are solid and semi-solid door and are constructed and finished in many ways.The inner core is either framed or laminated. The later makes a more solid and lasting door.These doors do not catch dust and are easy to clean.With the production of plywood in large quantities, flush doors are becoming more and more popular these days.These doors are mainly used as internal doors in residential buildings, restaurants, public and other important buildings.
85 (a) Framed Flush Door (b) Solid Laminated Flush Door.
86 7. Louvered doorsThese doors are similar to glazed and paneled doors. But in these doors, the spaces between the rails and stiles are filled with series of wooden members called louvers.The louvers are fixed into the stiles or made movable.In order that they may be effective and economical, are fixed at an angle of 45 degree.These doors allow free passage of light air and secure privacy and safety. But they collect dust easily and are difficult to clean.These doors are mostly used in school, workshops or at place where sufficient privacy is required besides admitting air and light freely.
88 8- Revolving doorsThese doors consist of four shutters, arranged diagonally, revolving on a common vertical axis.Paneled, glazed or both types of shutters may be used for these doors. They allow entrance on one side and exit on the other side.These doors are used where there is constant foot traffic of people coming in and going out of an entrance in public buildings such as offices, banks, restaurants, hotels, theatres, and other public buildings.They are also used in hill stations to prevent strong wind blowing inside the building directly.
89 9- Sliding DoorsThese doors consist of single or double steel or wooden shutters.They slide into the pockets provided in the masonry wall.These doors are commonly used for workshops, garages and on windows in shops etc.
91 10- Collapsible DoorsThese doors consist of frame work of rolled steel sections and are provided with rollers at bottom which roll on rails.These doors are rolled when they are to be opened or collapsed.Flat iron pieces are used cross wise and are fixed to vertical flat iron pieces at 12 to 15 cm centre to centre so as to form parallelograms. When pushed, the parallelograms get collapsed.These doors are used in public buildings such as banks, railway stations, sheds, godowns, workshops etc.
93 11- Rolling Steel DoorsThese doors are generally made of thin corrugated steel plates ( or sheets) which roll up on a roller or drum.The shutter slides in grooves in the side walls.The shutter may be counter balanced by sprigs so that it can be easily raised on lowered by hand.These doors are sufficiently strong and may be safely used in exposed places.These doors are mostly used for main entrance of shops, showrooms, and garrages
95 12- Wire-gauged doorsThese doors are normally hung on the same chowkhat (frame) as other door and window shutters of the frame.The thickness of the frame is increased suitably to cut the rebate for the wire gauged shutters.These doors allow free passage of the air and light and at the same time do not allow entrance of flies and mosquitoes inside the rooms of a building.These doors are mostly used in kitchens and dining rooms of residential buildings
97 TYPES OF FLOORSNormally the following types of floors are generally used: Brick floor.Earth floor.Cement concrete floor.Mosaic floor.Tile floor.Marble floor.Wooden floor.
98 MATERIALS FOR FLOORING The materials used for Ground floorconstruction are:Stones.Bricks.Concrete.Marble.Chips.Asphalt.
99 FACTORS AFFECTING SELECTION OF FLOORS 1- INITIAL COSTThe cost of floor covering is the most important thing.The expensive types of floor coverings are marble and teerrazzo (chips).Tiles and asphalt are less expensive whereas concrete and brick are the cheapest and are commonly used. 2- APPEARANCECo lour, texture and architectural beauty are the factors taken into consideration.
100 FACTORS AFFECTING SELECTION OF FLOORS ( -CTD- ) 3- DURABILITYResistance to wear and tear is an important factor for a floor covering.Resistance to temperature changes, humidity, disintegration and decay has alsoto be taken into account.Tiles, marble and concrete floor covering offer good resistance to these factors. Wherever heavy floor traffic is not anticipated bricks and wood blocks can be used.4- CLEAN LINESS OF FLOORA floor should be non absorbent and capable of being easily cleaned.All joints should be simple so that they can be made water tight as possible.Glass strips used for making panels, should not be more than 16 sq. ft. i.e. (4`x4`).
101 FACTORS AFFECTING SELECTION OF FLOORS ( -CTD- ) 5- DAMPNESSMoisture should not penetrate in the floor.They should be completely water tight.Wood, Rubber are not suitable in damp places, whereas tiles, bricks, concrete and Terrazzo is suitable for use on flooring which are subjected to dampness.6- INDENTATIOINMarks, depression due to furniture legs or ladies shoes should not make any impression on the floor.
102 FACTORS AFFECTING SELECTION OF FLOORS ( -CTD- ) 7- NOISELESSNESSThis is not an important factor for ground floor constructions, but it should be noiseless when traveled over.Rubber coverings and cork covering are most suitable.8- MAINTENANCEFor keeping floor in perfect condition it is necessary to clean, repair and apply any other treatment from time to time.Marble and concrete floors require less repair whereas wood blocks, need frequent maintenance.Concrete surfaces can not be repaired easily while tiles can be replaced quickly.
103 CONSTRUCTION OF FLOORS 1- BRICK FLOORINGBrick flooring is commonly used.The filling over which this floor is to be laid should be well compacted.The level of the flooring being known, the filling is excavated the desired depth.Generally two types of beds are provided.In the first type, after excavation the surface is leveled and a layer of 3// sand is spread over which a course of bricks is laid.In the second type, a lean cement concrete (P.C.C), one part of cement, 6 parts of sand and 18 parts of aggregates of 10 to15 cms in thickness is laid on the compacted bed.Flat brick flooring is laid into1:6 C/S mortar over a bed of ¾ // thick cement sand mortar.Bricks on edge flooring are laid into1:6 C/S mortar over a bed of ¾ // thick C/S mortar.
104 CONSTRUCTION OF FLOORS ( -CTD- ) 2- CEMENT CONCRETE FLOORINGThis type of floors are most commonly used both in residential and commercial buildings.The two components of a concrete floor are Base & Wearing surface (top surface).The flooring can be constructed either monolithic or non-monolithic.In monolithic floors, a base layer is laid and then immediately a concrete topping is provided and in non-monolithic the topping is laid after the base has set.
105 CONSTRUCTION OF FLOORS ( -CTD- ) DISADVATAGES OF MONOLITHIC FLOORSThe topping is likely to get damaged due to subsequent building operations.It is likely to develop hair-like cracks on account of small settlements which may occur in the base course immediately after it is laid.When the surface of the topping gets damaged, it is very difficult to repair it.The progress is slow since the topping can be laid only after the base course has sufficiently set to allow the workmen to lay the top layer.
106 CONSTRUCTION OF FLOORS ( -CTD- ) CEMENT CONCRETE FLOOR DETAILSTopping is laid in panels over a base thickness which varies 1// to 3//.If the thickness is 1-1/2// then it can be laid in single layer and if it is exceeding then it is laid in double layer.To avoid cracks due to shrinkage, the area of a panel is restricted to 4/ x 4/ (i.e. 16 sq. ft.).
107 CONSTRUCTION OF FLOORS ( -CTD- ) 3. MOSAIC OR TERRAZO FLOORINGThe base for terrazzo floor is of plain cement concrete (1:2:4).The topping shall not be less than 3/8// thick and shall be laid with a bottom layer of cement concrete (1:2:4).The total thickness of topping of cement concrete should mot be less than 1-3/8//.Normally 2// thickness is used, 1-1/2// concrete (1:2:4) and ½// mosaic.The mosaic topping shall consist of one part of cement (including15% to30% marble powder) and two parts of marble chips.The mosaic topping shall be laid while the bottom concrete is still fresh preferably on the next day or after 24 hours to have better bond.The surface should be rough to get better bonding.
108 CONSTRUCTION OF FLOORS ( -CTD- ) 4. TILE FLOORINGTiles of various shapes, sizes, thicknesses, color and surface finishes are manufactured for used as surface covering for floors.Floorings tiles are set on the concrete base with mortar.Special bedding made up of asphalt or portland cement is available for use over concrete base.The concrete bedding is generally 5// thick and is laid evenly with a slight rough surface at the top.After a period of 2 to3 days, a mortar layers of 1:1 mix is spread on the concrete bed and the tiles are set evenly with a thin a thin paste of cement applied to their sides.
109 CONSTRUCTION OF FLOORS ( -CTD- ) They are slightly topped till the cement comes out through the joints to the top surface.This extra cement is wiped off and the joints are cleaned.After2 to3 days, these joints are rubbed to chip off all the projecting edges or surfaces.The whole surface is then polished with a very soft carborundum stone.Finally the surface is washed with soap. If the tiles have glazed surfaces then this rubbing process is not suitable.
110 CONSTRUCTION OF FLOORS ( -CTD- ) 5. GLASS FLOORGlass floors are used wherever it is desired to admit light into the basements through the upper floor.The glass blocks are fitted within the frames of various thicknesses to transmit light at an angle to the farther areas in a room.Structural glass is available in the from of tiles or slabs and its thickness ranges from 12 to 30 millimeters.The framework is spaced closed apart so the glass can withstand loads coming over it. Glass flooring is not commonly used.
111 CONSTRUCTION OF FLOORS ( -CTD- ) 6. ASPHALT FLOORINGAsphalt mastic is a mixture of fine aggregates (sand), natural or artificial asphalt and coarse aggregates.It can be mixed hot and laid in continuous sheets or pressed into blocks which can be used as flooring.It can also be mixed with a mineral oil and asbestos and applied cold.While heating, the asphalt is stirred thoroughly so that the layer at the bottom may not get burnt, when the whole quantity is fused, sand or aggregates equal to twice the volume of asphalt is added gently and mixed thoroughly. This mixture is then ready for laying.
112 CONSTRUCTION OF FLOORS ( -CTD- ) 7. WOODEN FLOORINGThis type of floor construction is not extensively used but is popular for special purpose floors, e.g. in auditorium, hospitals.Wooden flooring should have a concrete base or should rest on joists spanning across walls which are constructed at suitable interval.For the fixing of wooden floors on concrete slabs, longitudinal railing strips are provided.
113 ROOFSThe covering provided over the top of an enclosure made for a building to keep out the sun, rain, wind and to protect the interior from exposure to the weather is known as roof.
114 ROOFS (-ctd-)A roof usually consists of frame work provided with a suitable covering at its top.A good roof is as essential as a safe foundation of a building.Roofs must, therefore, be well designed and constructed to meet the requirements of different climates and covering materials locally available.The form of construction of a roof is governed by the plan of a building, span, the type of covering material locally available and the architectural appearance required.The roof covering to be provided should be economical and most suitable according to the nature of the building.
115 CLASSIFICAION Sloping, pent or pitched roofs Flat or terrace roofs (Sloping roofs are suitable for the area where rainfall and snowfall are heavy, whereas, flat roofs are suitable for the area where rainfall is meager i.e. of low intensity, and there is no snowfall)Shelled roofsDomes
117 TYPES OF SLOPING ROOFS (-ctd-) Shed Roof:- A slopping roof having slope only in one direction is called a Shed Roof. This is the simplest type of sloping roof and is used for smaller spans.2. Gable Roof:- A sloping roof having slope in two directions is called a Gable Roof. This type of sloping roof is used for larger span.3. Hipped Roof:- A sloping roof having slope in four directions is called Hipped Or Hip Roof. This type of sloping roof is mostly used for buildings in hilly area.4. Gambrel Roof:- A sloping roof having slope in two directions with a break in the slope is known as Gambrel Roof. This type of sloping roof is mostly used for buildings in hilly area.
119 TYPES OF SLOPING ROOFS (-ctd-) 5. Mansord roof:- A sloping roof having slope in four directions with a break in slope is known as Mansard Roof6. Saw tooth or north light roof:- A sloping roof having glazing fixed on the steep sloping sides of the roof is called Saw Tooth Or North Light Roof. This is generally used in factories where more light is required.
120 IMPORTANT TECHNICAL TERMS Ridge:- The highest point or line of a sloping roof where the two opposite slopes meet is known as ridge. Ridge piece:- A horizontal piece of timber which runs the highest level (bridge) of a sloping roof is called ridge piece. Eaves:- The lowest edges of the surfaces of a sloping roof are called eaves. Eave’s board:- A wooden board fixed along the eaves at the end of common rafters is known as eaves board or facia board. Gutter is usually supported at eaves board.
122 IMPORTANT TECHNICAL TERMS (-ctd-) Rafters:- The members which support the covering material of a sloping roof are called rafters. Hip:- The line of intersection of sloping surfaces of a roof forming an external angle exceeding 180° is known as hip. Hip rafter:- The rafter lying along the hip in a sloping roof is termed as hip rafter. Valley:- The line of intersection of two sloping surfaces of a roof forming an external angle less than 180° is known as valley. Valley rafter:- The rafter lying along the valley in a pitched roof is known as valley rafter.
123 IMPORTANT TECHNICAL TERMS (-ctd-) Jack rafter:- The short common rafters which run from a hip rafter to the eave of a sloping roof are called jack rafters. Common rafters:- The members supporting the battens or boardings under the covering of a sloping roof are known as common rafters. Gable:- The end of a sloping roof finished in a vertical triangle is called gabled end or gable. Barge:- The finished edge of slating or tiling over-hanging a gable wall is called barge. Barge board:- Wooden planks fixed to the ends of the common rafters projecting beyond the gabled end of a sloping roof is called a barge board.
124 IMPORTANT TECHNICAL TERMS (-ctd-) Purlins:- The wooden or steel members laid horizontally to support the common rafters of a sloping roof are called purlins. Cleats:- The pieces of timber or angle-iron which are nailed or screwed (for timber), riveted or welded (for angle-iron) on the trusses, to support the purlins are known as cleats. Battens:- The pieces of wood which are directly nailed to the common rafters are called battens. The roof coverings are directly laid over battens. Pitch:- The inclination of the side of a slopping roof to the horizontal surface is called pitch of the roof. It is usually expressed as the ratio of the rise to the span or in degrees. Truss:- A frame work of members arranged in triangles is called a truss.
125 STAIRS AND STAIR CASESA series of steps which provides access from one floor to another is called a stair and the part of the building accommodating the stair is known as stair case.A stair may be constructed with steps either rising continuously or with a break in the form of landing in between.All the steps should be so designed and constructed that up and down movements from one floor to another can be made with ease, comfort, quickness and safety.
126 STAIRS AND STAIR CASES (-ctd-) The stairs may be consisting of any suitable material such as timber, bricks, stones, steel, reinforced cement concrete etc.The provision of a stair in a building is essential for the movements of inmates from one floor to another floor or roof of that building.Now-a-days, in most modern residential and public buildings of multi-storey nature, a lift system is provided for convenience and quick movements of the users from one floor to the other. In such buildings too, a stair is essential for the movements of the users in case of failure of the lift system due to some mechanical defect or non-supply of electric power.
127 IMPORTANT TECHNICAL TERMS Step:- The combination of a tread and a riser supported by a string is called a step. Tread:- The horizontal top surface of a step on which foot is placed while going up or coming down a stair is known as tread. Riser:- The vertical face of a step is called riser. Going or run:- The horizontal distance between any two adjacent risers in a stair is called going or run. Rise:- The vertical distance between any two adjacent treads in a stair is called rise. Bull-nose step:- The step with one or both ends rounded is known as bull nose step. This type of step is generally provided at the bottom of a flight and is always projecting beyond the face of the newel post.
129 IMPORTANT TECHNICAL TERMS (-ctd-) Nosing:- The projecting edge of a tread beyond its riser in a step is called nosing. The line joining nosing of all steps in a flight is known as line of nosing. Pitch or slope:- The angle between the line of nosing and the floor or landing is called pitch or slope of a stair. String or stringer:- The inclined support to which the ends of treads and risers of a stair are fastened is called a string or stringer. Hand rail:- As inclined member at a convenient height projecting above steps of a stair to provide assistance and safe-guard to the users is called hand rail. Balusters:- The vertical members provided in between the steps and the hand rail are called balusters. These members act as intermediate supports to the hand rail. Newel or newel post:- The posts provided at the bottom, top and all the turning points in a stair to support the hand rail are known as newels or newels posts.
130 IMPORTANT TECHNICAL TERMS (-ctd-) Soffit:- The under surface of a stair is called soffit. Flier:- A step of uniform width is called flier. This type of step is rectangular in plan. Such steps are always preferred even at turning points of a stair as they are safe for quick movements of the uses. Winder:- A step of non-uniform width is known as winder. This type of step is usually triangular in plan. Such steps are only provided for changing the direction of a stair and should be avoided as far as possible since they are dangerous for quick movement of the users. Landing:- The horizontal platform provided in between any two flights of a stair is called landing. The landing which provides 90° turn in the layout of a stair is known as quarter space landing and if the turn is through 180°, it is called half-space landing Flight:- A series of steps without any break in between is known as flight. Head room:- The height between the line of nosing to the soffit of a flight or ceiling of roof immediately above is called head room. Width of a stair case:- The width of enclosure accommodating the stair in a building is called width of stair case. It depends upon the layout and width of the stair.
131 REQUIREMENTS OF A GOOD STAIR It must be well designed so as to provide maximum comfort, ease and safety.It should be centrally located in a building.All the steps should have uniform width and heightThe pitch or slope of a stair should neither be more than 40° nor less than 24°.The width of a stair must not be less than 0.85 m in any case.
132 REQUIREMENTS OF A GOOD STAIR(-ctd-) The maximum number of steps in a flight should not be more than 15.The head-room must not be less than 2.1 m vertically or 1.5 m at right angles to the line of nosing.The height of the hand rail should neither be more than 0.85 m nor less than 0.75m measured vertically from the line of nosing to the top of hand rail.It must be constructed of sound materials.It should have good workmanship.It must be properly ventilated and lighted.
133 PRINCIPLES TO BE OBSERVED WHILE PLANNING AND DESIGNING A STAIR Relation between going and rise of a step2 x Rise + Going in cm = 55 to 60 cmGoing x Rise, both in cm = 400 to 430 cm2While designing steps, take 30 cm going and 14 cm rise as a standard value. For each 2.5 cm subtraction from going, add 1.2 to 1.3 cm to the rise.The following dimensions of going and rise are generally used for different buildings:-Residential buildings = 25 cm x 16 cmPublic buildings such as theatres, colleges, banks etc=27 cm x 15 cm or 30 cm x 14 cm.Industrial buildings = The going should not be less than 25 cm and rise not more than 19 cm.It should be noted that the rules given above only act as guide but the actual dimensions of going and rise depend upon the space available, height of the building and layout of the stair.
134 PRINCIPLES TO BE OBSERVED WHILE PLANNING AND DESIGNING A STAIR 2. Pitch of the stair:- The pitch or slope of the stair should not be more than 40° and should not be less than 25° for comfortable ascend and descend. 3. Width of stair:- The width of a stair must not be less than 0.85 m so that a person going up can pass a person coming down without any difficulty. The minimum width of stair in a residential building should be 1.05 m whereas in case of a public building, a minimum width of 1.5 m is desirable. 4. Length of flight:- The number of steps in a flight should not be more than 15 otherwise it becomes difficult to move up and down the flight. The minimum number of steps in a flight should be 3.
135 PRINCIPLES TO BE OBSERVED WHILE PLANNING AND DESIGNING A STAIR (-ctd-) 5. Width of landing:- The width of landing should not be less than the width of its stair case. 6. Head room:- An adequate head-room must be provided. It should not be less than 2.1 m. 7. Winders:- They should be avoided as far as possible. But they are to be provided when the area of staircase is limited. In such case, winders should be placed at the lower end of a flight. In a quarter space i.e 90° turn, only three winders should be provided. 8. Hand rails and balustrades:- A stair should be provided with a hand rail along with balustrades to provide assistance, comfort and safety to the users. The height of hand rail should neither be more than 0.85 m nor less than 0.75m.
136 PRINCIPLES TO BE OBSERVED WHILE PLANNING AND DESIGNING A STAIR (-ctd-) 9. Materials:- The stair should be constructed from sound materials preferably of fire resisting quality. It should be constructed of R.C.C. according to building bye-laws being followed in the locality. 10. Location:- The staircase should be located in such a position that it is easily and quickly approached. A central position in a building would be ideal. Both light and ventilation should be available especially at turning points. In a residential building, the stair should be located near the main entrance and screened from outside for privacy. In public buildings, it should preferably be located obvious from the main entrance.
137 CLASSIFICATION OF STAIRS ACCORDING TO THEIR LAYOUT 1- Straight flight stairs:- The stair which rises from one floor to another in one direction is known as straight flight or simply straight stair (see fig. 2 a). This type of stair may be constructed with or without landing. This type of stair is only suitable for a long and a narrow staircase.2- Quarter turn stairs:- The stair which turns through 90° either to the left or to the right is known as quarter turn stair (see fig. 2 b & c). This type of stair may be provided with winders as shown in fig. 2 (b) or with a quarter-space landing as shown in fig 2(c). This type of stair is suitable where the width staircase is more but it has got limited length.
139 CLASSIFICATION OF STAIRS ACCORDING TO THEIR LAYOUT 3- Half turn stairsThe stair which turns through 180° is known as half turn stair (see fig. 2 d &c). In such stairs, the adjacent flights are in opposite directions separated by half-space landings, two sets of winders or two quarter space landings according to the space available.Half turn stairs are further classified into the following two types:-(a) Dog-legged stairs:- A half turn stair with no space between its flights is known as dog legged stair (see fig. 2 d). This type of stair is suitable where the width of the stair case is limited and is commonly used for single or double storied modern buildings.(b) Open well stairs:- A half turn stair with a space (called well) between its flights is known as open well stair (see fig. 2 e and f). This stair is also known as an open newel stair when the well left between the flights is of rectangular shape see fig. 2 (e). If the space for this type of stair is limited, a short flight is introduced on the narrow side of the well with two quarter space landings as shown in fig. 2 (f).This type of stair is suitable for multi-storied buildings as in this case the well allows for top lighting.
140 CLASSIFICATION OF STAIRS ACCORDING TO THEIR LAYOUT (-ctd-) 4. Geometrical stairs: A half turn stair in which the dwell is of curved shape between the forward and backward flights is called geometrical stair (see fig. 2 g). In this type of stair, the change in direction is obtained by winders. It provides easy turning but is tiresome as it is generally without landing. This type of stair is suitable for single or double storied buildings. 5. Circular stair:- The stair which is provided in a circular stair case is called circular stair (see fig. 2 h). In this stair, the strings and the hand rails are continuous and the change in direction is obtained by winders. All the steps may be supported by a newel at the centre or there may be a circular well hole. A circular stair having all is steps radiating from a central newel is known as spiral stair. This type of stair is suitable when a limited space is available for the stair case. Iron spiral stairs are very suitable for back door entrance as they occupy very little space. 6. Bifurcating stairs:- This stair having its bottom flight wide which is divided into two narrow flights at the landing at right angles in the opposite direction is called a bifurcating stair (see fig. 2 i). This type of stair is suitable for public buildings, assembly halls, railway foot bridges etc.
141 MAINTENANCE OF BUILDINGS The art of up keeping the different parts of buildings in their best conditions to ensure neat appearance and a fair life of service of those parts is called maintenance of buildings.Maintenance of buildings may include cleaning overhauling, general repair and replacement of defective parts and special repair of defects occurring due to their poor design and workmanship.The object of building maintenance is to ensure neat appearance and stability of the building
142 CLASSIFICATION OF BUILDING MAINTENANCE JOBS Maintenance jobs of building are divided into following two categories 1. Routine maintenance 2. Special Repair
143 (a) ROUTINE MAINTENANCE Def: The day to day or thorough repairs which are carried out in buildings after specified periods are known as routine or periodic maintenanceExplanation: Routine maintenance of buildings includes the following items of workRepair of damaged plaster surfaceWhite washing and colour washingDistemperingPainting of timber and steel surfaceRepair to damaged part flooring
144 ROUTINE MAINTENANCE (-ctd-) Removal stains from concrete and terrazzo floorRe-polishing a terrazzo and mosaic flooringRepair to worn out timber floor polishing and waxingReplacement of glass panesReplacement of decayed timber and replacement of fittingsEasing of doors and windowsCleaning of fire chimneys, gutters, etc
145 (B) SPECIAL REPAIRSDef: The repairs that are done to overcome special problems as soon as they occur are known as special repairs. These repairs are very difficult and require more attention for their carrying out.Explaination:Special repairs of the buildings include the following items of maintenance works:Strengthening of foundations and foundations soilRectifications of Leaking roofs
146 SPECIAL REPAIRS(-ctd-) Repair to damage concrete surfacesRepair to cracks in masonry wallsRepairs at the window sills & joinery works at the roof level of buildingProviding damp proof course in the existing buildingRepairs to the damp floorsAnti termite treatment in the maintenance of buildingsRepairs to expansion joints