2Next Generation Science/Common Core Standards Addressed! CCSS.ELA Literacy. RST.9‐10.3 Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks, attending to special cases or exceptions defined in the text.CCSS.ELA Literacy. RST.9‐ 10.5Analyze the structure of the relationships among concepts in a text, including relationships among key terms (e.g., force, friction, reaction force, energy).CCSS.ELA Literacy. RST.11‐ 12.3 Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the textCCSS.ELA Literacy. RST.11‐12.4 Determine the meaning of symbols, key terms, and other domain‐specific words and phrases as they are used in a specific scientific or technical context relevant to grades 11–12 texts and topics.CCSS.Math.Content.HSGCO.D.12 Make formal geometric constructions with a variety of tools and methods (compass and straight edge, string, reflective devices, paper folding, dynamic geometric software, etc.). Copying a segment; copying an angle; bisecting a segment; bisecting an angle; constructing perpendicular lines, including the perpendicular bisector of a line segment; and constructing a line parallel to a given line through a point not on the line
3Bell Work/Student Learning Objectives Discuss how to plan and lay out a job.Explain how to mix mortar and lay blocks.Explain how to tool joints, patch holes, and clean smears.
5Concrete masonry Popular type of agricultural construction. Concrete blocks are strong, durable, fireproof, rodent and termite proof, and do not rotConcrete masonry units, also called concrete blocks, come in two types and several standard sizes
6General Types Two general types: hollow solid Standard or heavyweight block:Made from Portland cement, water, sand, gravel, and crushed stone
7General Types Lightweight blocks: Made from Portland cement, water, and lightweight aggregates, such as cinders, slag, or shale.Weighs half as much as a standard blockEasier to handle but have greater insulating value
8Block Sizes Even number widths 4, 6, 8, 10, and 12 inches Even number heights4 and 8 inches8 ×8 ×16 blockWidely used to build agricultural structures.Actual dimensions are: 7 5 /8 ×7 5 /8 ×15 5 /8Mortar completes the dimensions (3/8 layer)
9Block SizesWhen the standard 3/8 mortar joint is added, the block with one mortar joint is 8 inches high and 16 inches long.
11Block Types Building dimensions Total length and width in inches should be divisible by eight so that full blocks and half blocks will be usedBlocks come in a variety of shapesCorner block and stretcher blocks are the most common
12Block Types Stretcher block: has ribs on both ends Usually with three cores or holes in the blockUsed between the corners
13Block TypesCorner block: Square across one end and has ribs on the other endUsed at the corner when laying blocks Use the dimensions to figure theUse the dimensions to figure the number of blocks needed.
15Bonding MaterialsMortar: Bonding material made of sand and masonry cementMix one part cement to 2½ to 3 parts masonry sand.Masonry cement: Type of cement used to make mortar while Portland cement is used to make concrete
16Bonding MaterialsMasonry sand is fine sand while the sand used in concrete is coarse sandUse the following as a guide to calculate the amount of cement and sand to purchase:in a 1:3 mix, 1 bag of cement and 250 pounds of sand will lay 100 eight inch blocks.
17Laying out the Structure Building must be laid out prior to digging the footing and pouring itSurveying instrumentsEasiest, quickest, most accurate way to lay out building’s cornersGenerally laid out parallel to property lines or other buildings
18Laying out the Structure Surveying level and target rod: Helps to set square corners and the proper height of the foundation wall Dimensions should always be doubled checked Measuring for equal diagonals is a way to check for square corners.
19If no Surveying Equipment Establish a base line and use the 3–4–5 right triangle method to establish square corners
20Outer Supports Batter boards: Outside supports used to stretch strings stretch strings: set up when corner stakes are in placeThe batter board includes three stakes and two horizontal 1 x 4 or 1 x 6’sThe strings mark the outside of the foundation wall and the top of the foundation
21Outer SupportsPlumb bobs can be helpful to insure that the strings intersect over the corner stakeUse powdered lime or spray paint to mark the ground for digging the footing
22Outer Supports Remove strings while the digging is done. The surveying level and the target rod are used to set the grade stakes or forms in the trench
23Outer SupportsThe footing trench should be dug down to firm soil below the frost lineFrost line: Deepest point in the soil where the ground freezes in a typical yearThe bottom of the trench should be flat and levelMost New Mexico building codes require the footing to be a foot deep.
24Outer Supports Footing rules are: Set at or below the frost line, pour a minimum of 8 inches for 8 inch blocks, 10 inches for 10 inch blocks, etc., andhave the footing at least twice as wide as the foundation.
25Outer Supports After footing is poured and forms are removed: Sweep off the footing and re-stretch the stringsThe plumb bob can be used at the string intersection to help mark the corners on the footingThis provides you with a straight line for laying the block wall
26Outer SupportsSnap a chalk line on the concrete footing to mark the location of the outside of the first row of concrete blocksBeginning block layers sometimes lay out the first row of blocks without mortar to make sure the layout was planned properly
27Mixing Mortar and Laying Blocks Good mortar: Absolutely necessary for good workmanship and a good finished wallProcess of laying concrete blocks requires considerable know-how and skillConcrete masonry work may be contracted to professionals
28Concrete Masonry You start by mixing mortar and carrying blocks Start with:Clean, dry blockswatermasonry sandmasonry cementconcrete blocksquality tools
29Mixing Mortar Strength of a mortar joint is affected by: Quantity of cementing material,Portions and moisture content of the mortar, andQuality of the workmanship.
30Mixing MortarMix one part masonry cement to 2½ to 3 parts masonry sand with enough to make a workable mix that is plastic enough to support blocks on a 3 /8 inch mortar joint until it has setIf masonry cement is not available:Use Combination of Portland cement and hydrated lime
31Mixing Mortar Mix mortar in: A leak proof box with shallow sides, A wheelbarrow, orA mixing machine
32Mixing Mortar To hand mix: Use a mortar hoe (a hoe with two large holes in the blade) to dry mix the cement and sand until a uniform color exists.Gradually add water and continue mixing with the mortar hoe until the mortar is plastic and workable
33Mixing Mortar If mortar is: Too stiff: Will not bond well and results in a thick jointToo thin: Will be squeezed out by the weight of the block resulting in narrow mortar joints
35Concrete LayoutLocate the corners and lay out the first course, without mortar, to check the layoutFull mortar bed: Using mortar on both horizontal and vertical cross webs of the blockFace shell mortar bed: Using mortar on only the horizontal cross webs of the block
36Concrete LayoutNormally the first course uses a full mortar bed and the other courses use a face shell mortar bedAlways lay the blocks with the thicker end of the face shell upThis provides a larger area on which to place the mortar
37Laying first course of Blocks Mason’s line: Nylon string that is stretched tight to mark the top and outside edge of a row of concrete blocksOnce the first course corner blocks are laid in position stretch it so that the first course will be straightButtering refers to putting mortar on the end of a block
38Laying first course of Blocks Block layers often stand several blocks on end and butter the endsTo get a better bond to the block:Flip mortar off trowel onto block with snap of the wristTo place the block in position:Pick it up with both hands and use a swinging motion to lower it into position
43Laying first course of Blocks Block trowel: Triangular shaped piece of metal with a wooden handleBlock hammer: Can be used to tap blocks into place as well as cutting blocks
44Laying first course of Blocks Block chisel: Three or four inch wide metal chisel that can be hit with the block hammer to mark and cut concrete blocks
45After first course of blocks Use face shell mortar beds and lay up 4 or 5 courses of blocks at the cornersCheck for each block’s:Level, plumb, and alignmentChecking horizontal spacing:Use a straightedge or four foot level
46After first course of blocks Since each course is back spaced a half block, the corner of each back stepped row should touch the diagonally positioned straightedge.Story or course pole: Board with markings eight inches apartUse to ensure that the horizontal mortar jointing are running 3 /8 inches thick.
47After first course of blocks Key to a straight true wall:Using the mason’s line between the corners as a guideMost difficult part of laying blocks:Usually laying the closure block
48After first course of blocks Closure block: Last block laid to complete the rowIf vertical mortar joints have been 3/8 inches the opening for the last block should be 16 3/8 inches long (2 3/8 inch mortar joints and a 15 5/8 inch block)
49After first course of blocks Closure block:Must be buttered on both ends orPreviously laid block must be butteredIf mortar falls off the end of the block as swung into place, block should be removed and re-buttered
50Tooling joints and removing smears Completes job resulting in a professional appearance to the job
51Tooling JointsProcedure that pushes the mortar into the groove between the blocksCreating an improved bond of the mortar to the blockResults in a weather-tight joint with a neat appearanceJointer: Concave or V- shaped metal tool with a handle and turned up ends
52Tooling Joints Brick layers often use a raker joint. Raker joint: Tool that moves the mortar from the joint to depth of approximately 3/8 inches
53Removing mortar burrsAfter joints have been tooled, trim off with face of the wall with the trowel
54Crooked BlocksDo not attempt to move or straighten the block once the mortar has stiffened or even partly stiffened
55Mortar Dabs On block: Should be allowed to dry Use trowel to knock dab offPiece of a concrete block to rub out remaining particles
56SmearsWhen laying blocks, be careful not to smear mortar into the blocksOnce the smears are in the block it is impossible to remove themA wire brush will help but is unable to remove mortar from pores in the blockMuriatic acid rinse will help clean the wall and make paint smears less noticeable
57Review / Summary Discuss how to plan and lay out a job. Explain how to mix mortar and lay blocks.Explain how to tool joints, patch holes, and clean smears.