1. Internal solid plastering
Internal plastering covers walls and ceilings, prior to decoration.
A variety of materials can be used to provide a sound, flat, smooth surface for decoration.
Sometimes, decoration is needed.
Plastering provides sound and thermal insulation.
It also improves levels of hygiene, allowing for wiping down.

2. History of plastering Plaster is at least 4,000 years old.
It was used by the Egyptians (in the pyramids) and the Greeks (who produced plasterwork in 500 BC).
The Romans introduced plastering to England.
Henry III admired the whiteness and fineness of gypsum (‘Plaster of Paris’), so he brought it to England.
Plasterers were formed into a guild (a company) which was granted a charter by Henry VII.
Decorative ceiling and frieze

3. Examples of some tools and equipment used for internal plastering
Hawk
Trowel
Floats
Spirit level
Gauging trowel
Spot board and stand
Floating rules
Mixing equipment
Internal angle trowels
Other tools and equipment required
Two sizes of plastering trowel

4. Preparation of background
What is adhesion?
What is suction and how does it improve or hinder a plasterer?
Block work toothed into facing brickwork

5. Surface key is it good , moderate or poor
Good key:
if joints are raked out
keyed blocks
when keyed bricks are used
Moderate key:
flush brickwork or blockwork
Poor key:
unless surface has been keyed in manufacture
Preparation required prior to plastering
Brush and damp down according to suction.
Rake out soft joints in old brickwork.
Test suction if poor and apply spatterdash coat.
Mechanical key, hand key or spatterdash coat.
Test with bonding agent (PVA).
Types of background
Normal clay bricks or blocks
Dense clay brickwork, blockwork, calcium silicate blocks, concrete blocks
Dense concrete, engineering bricks
Painted brickwork, glazed tiles, glazed brickwork

6. Types of background in British Standard 5262
Dense, strong and smooth materials
Moderately strong, porous materials
Moderately weak, porous materials
No fines concrete
Composite backgrounds

7. Forming a key Purpose of a key Forming a mechanical key
Forming a spatterdash coat
Using liquid PVA or EVA for forming a key
Forming a key by hacking the surface

8. Preparation checklist
Brush down background to clean it.
Remove mortar snots from joints, internal and external angles.
Make a key (if needed) to background.
Test background for suction; treat if necessary.
Place drop boards at bottom of wall to catch falling materials and keep floor cleaner.
Fix EML to timber wall and soleplates as necessary.
Fix angle beads.
Set up spot board and stand; wet in the board.

9. What is contained in a specification?
Type of material
Number of coats
Thickness of plaster
Standard of work

10. Materials used in plastering
Sand
Lime
Cement
Plaster

11. Sand Types and sources of sand What is meant by a well-graded sand?
What is the purpose of sand?
The effects of bulking
Performing a simple site test for sand
What is silt and how does it affect plastering sand?
Sand contained in a sand bay with protective covering sheet

12. Faults with poor quality sand
Symptom
Result
Possible causes
Delayed set or total failure
Weakness, shrinkage, cracking, delayed expansion
Too much clay
Very slow set of gauged lime mortar
Delay in build
Too much clay, animal or vegetable matter (e.g. leaves)
Low finished strength or mortar
Poor sticking of backing coats
Too much sand; too much clay
Efflorescence, dampness and rusting of metalwork
Unsightly appearance, damage to brickwork
Too much salt
Poor workability
Poor stickability
Badly graded sand
Rust-coloured staining
Lots of expansion
Too much iron impurity
Blowing of plasters and rendering
Bond failure
Clay balls or coal particles

13. Lime Manufacture of lime Types of lime Hydrated lime Hydraulic lime
Purpose of lime in a plastering mix
A lime works

14. Ordinary Portland cement
Raw materials of OPC
Manufacture of cement
Hardening and curing of cement
Other types of cement
Lightweight cement-based materials

15. Plaster Chemical formula of plaster CaSO4 2H2O Setting of plaster
Types of plaster and their uses
Storage of plaster and effects of poorly stored plaster
Method of mixing different types of plaster

16. Additives Expanded Perlite Vermiculite Coloured pigments Plasticiser
Waterproofers
Hardeners

17. Proportioning and gauging plastering materials
Method of gauging materials
Traditional cement, lime, sand mixes
Mixing in a trough
Mixing in a bucket or drum
Mixing by cement mixer
Mixing by hand
Mixing of lightweight plaster in a trough, using a larry/rake. Work station set up.

18. Plaster coats – method of work
One-coat work
Two-coat work
Three-coat work
Dubbing-out coat
Render coat
Application of lightweight plaster

19. Forming box or broad screed
The purpose of screeds
The method of forming screeds, horizontally and vertically
Method of ruling off screeds
Filling in between screeds
Method of forming a key between plaster coats
Ruling in a vertical screed

20. Dot and screed or plumb and dot
Use of the dot and screed or plumb and dot system
Method of forming dot and screed and
plumb and dot systems
Plumbing in
horizontal screeds
Ruling in from horizontal screeds
Use of a plumb bob and gauge
Plaster dot

21. Setting coat Method of forming a finishing coat depends on background
Finishing coat should not be stronger than backing coat
Purpose of a finishing coat
Method of forming a finishing coat to a floated background
The setting system; trowel, trowel, and trowel, float, trowel
A bucket of mixed finishing plaster

22. Setting coat to a plasterboard ceiling: applying reinforcement
Types of reinforcement of plasterboard joints
Application of reinforcement
Position of reinforcement to a ceiling

23. Plastering a ceiling or wall on plasterboard in one coat system
Applying a finishing coat to a ceiling
Applying a finishing coat to a partition
1st coat lay between reinforcement
2nd coat laid over whole ceiling
Always work leaving behind finished work
Trowel up leaving a finished matt surface

24. Beads (metal and plastic trims)
Purpose of beads
Types of beads available
Method of fixing of angle beads
Standards required for the fixing of beads
Fixing and levelling in an angle bead

25. Forming window openings, reveals and attached piers
Method of fixing beads around windows
Using timber rules around window openings
Forming reveals to window openings using reveal gauge
Forming returns and corners to attached piers

26. Forming attached piers (1)
What is an attached pier?
Back wall floated flat and keyed
Looking down onto an attached pier
An attached pier

27. Attached and independent piers (2)
Fix angle beads or timber rules plumb and straight
Check at top, middle, bottom, for equal measurement on face
When using angle beads check for squareness at top, middle and bottom
Float and set face and returns when using beads
When using rules float face, return rules onto face. Float and set returns
Return rules back onto return and set face

28. Lining in attached piers
Method of lining in face of pier
Angle beads fixed at the two ends
String through line
Place a nail or piece of timber between string and nosing of two end angle beads
Fix intermediate angle beads checking for plumb and straightness
Check that nosing of bead does not fail on the string
Lining through a row of attached piers

29. Independent piers
Lay floating rule on floor thickness of floating from face of pier
Mark along rule with a pencil
Using building square against rule mark floor
Continue around pier
Place nosing of bead on intersection of lines
Setting out and squaring in an independent pier

30. Floating and setting coat to a ceiling
Set up a datum line
Position of dots on ceiling by using the building square
Positioning and ruling in screeds using dots on ceiling
Float up ceiling off of screeds
Form a finishing coat to ceiling
Setting out of dots to a ceiling

31. Floating a beam Fix and line through beads
Check squareness of side checks of beam
Check measurement of soffit of beam
Position of screeds and ruling in
Method of finishing beam
Worm’s eye view of a ceiling beam

32. Method of patching a ceiling
Method of forming repairs to a wood lath ceiling
Method of forming repairs to a plasterboard ceiling

33. Making good to a wall 1. Brush down damaged area; remove dust.
2. Rake out mortar joints to form key.
3. Remove plaster to form undercut under existing plaster.
4. Wet in background area and undercut, or coat with PVA adhesive.
5. When PVA is tacky, add plastering material to repair.
6. Rule in floating coat, then key to receive finishing coat.
7. When plaster set, cut back floating – especially around edges of repair.
8. Wet in surrounding area and add finishing coat.