# Planning, Laying Out, and Tooling Concrete Block

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Planning, Laying Out, and Tooling Concrete Block

Next 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 text CCSS.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

Bell 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.

Terminology Batter boards Block chisel Block hammer Block trowel
Closure block Concrete masonry units Corner block Face shell mortar bed Frost line Full mortar bed Jointer Lightweight blocks Mason’s line Masonry cement Masonry sand Mortar Mortar hoe Raker joint Standard or heavyweight blocks Story or course pole Stretcher block Tooling joints

Concrete masonry Popular type of agricultural construction.
Concrete blocks are strong, durable, fireproof, rodent and termite proof, and do not rot Concrete masonry units, also called concrete blocks, come in two types and several standard sizes

General Types Two general types: hollow solid
Standard or heavyweight block: Made from Portland cement, water, sand, gravel, and crushed stone

General Types Lightweight blocks:
Made from Portland cement, water, and lightweight aggregates, such as cinders, slag, or shale. Weighs half as much as a standard block Easier to handle but have greater insulating value

Block Sizes Even number widths 4, 6, 8, 10, and 12 inches
Even number heights 4 and 8 inches 8 ×8 ×16 block Widely used to build agricultural structures. Actual dimensions are: 7 5 /8 ×7 5 /8 ×15 5 /8 Mortar completes the dimensions (3/8 layer)

Block Sizes When the standard 3/8 mortar joint is added, the block with one mortar joint is 8 inches high and 16 inches long.

Block Types Building dimensions
Total length and width in inches should be divisible by eight so that full blocks and half blocks will be used Blocks come in a variety of shapes Corner block and stretcher blocks are the most common

Block Types Stretcher block: has ribs on both ends
Usually with three cores or holes in the block Used between the corners

Block Types Corner block: Square across one end and has ribs on the other end Used at the corner when laying blocks Use the dimensions to figure the Use the dimensions to figure the number of blocks needed.

Other types of blocks!

Bonding Materials Mortar: Bonding material made of sand and masonry cement Mix 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

Bonding Materials Masonry sand is fine sand while the sand used in concrete is coarse sand Use 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.

Laying out the Structure
Building must be laid out prior to digging the footing and pouring it Surveying instruments Easiest, quickest, most accurate way to lay out building’s corners Generally laid out parallel to property lines or other buildings

Laying 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.

If no Surveying Equipment
Establish a base line and use the 3–4–5 right triangle method to establish square corners

Outer Supports Batter boards: Outside supports used to stretch strings
stretch strings: set up when corner stakes are in place The batter board includes three stakes and two horizontal 1 x 4 or 1 x 6’s The strings mark the outside of the foundation wall and the top of the foundation

Outer Supports Plumb bobs can be helpful to insure that the strings intersect over the corner stake Use powdered lime or spray paint to mark the ground for digging the footing

Outer 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

Outer Supports The footing trench should be dug down to firm soil below the frost line Frost line: Deepest point in the soil where the ground freezes in a typical year The bottom of the trench should be flat and level Most New Mexico building codes require the footing to be a foot deep.

Outer 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., and have the footing at least twice as wide as the foundation.

Outer Supports After footing is poured and forms are removed:
Sweep off the footing and re-stretch the strings The plumb bob can be used at the string intersection to help mark the corners on the footing This provides you with a straight line for laying the block wall

Outer Supports Snap a chalk line on the concrete footing to mark the location of the outside of the first row of concrete blocks Beginning block layers sometimes lay out the first row of blocks without mortar to make sure the layout was planned properly

Mixing Mortar and Laying Blocks
Good mortar: Absolutely necessary for good workmanship and a good finished wall Process of laying concrete blocks requires considerable know-how and skill Concrete masonry work may be contracted to professionals

Concrete Masonry You start by mixing mortar and carrying blocks
Start with: Clean, dry blocks water masonry sand masonry cement concrete blocks quality tools

Mixing Mortar Strength of a mortar joint is affected by:
Quantity of cementing material, Portions and moisture content of the mortar, and Quality of the workmanship.

Mixing Mortar Mix 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 set If masonry cement is not available: Use Combination of Portland cement and hydrated lime

Mixing Mortar Mix mortar in: A leak proof box with shallow sides,
A wheelbarrow, or A mixing machine

Mixing 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

Mixing Mortar If mortar is:
Too stiff: Will not bond well and results in a thick joint Too thin: Will be squeezed out by the weight of the block resulting in narrow mortar joints

Concrete Layout Locate the corners and lay out the first course, without mortar, to check the layout Full mortar bed: Using mortar on both horizontal and vertical cross webs of the block Face shell mortar bed: Using mortar on only the horizontal cross webs of the block

Concrete Layout Normally the first course uses a full mortar bed and the other courses use a face shell mortar bed Always lay the blocks with the thicker end of the face shell up This provides a larger area on which to place the mortar

Laying 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 blocks Once the first course corner blocks are laid in position stretch it so that the first course will be straight Buttering refers to putting mortar on the end of a block

Laying first course of Blocks
Block layers often stand several blocks on end and butter the ends To get a better bond to the block: Flip mortar off trowel onto block with snap of the wrist To place the block in position: Pick it up with both hands and use a swinging motion to lower it into position

Laying first course of Blocks
To make sure a laid block is level plumb, and aligned: Use a level Level the blocks by tapping the block with the handle of the trowel

Laying first course of Blocks
Block trowel: Triangular shaped piece of metal with a wooden handle Block hammer: Can be used to tap blocks into place as well as cutting blocks

Laying 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

After first course of blocks
Use face shell mortar beds and lay up 4 or 5 courses of blocks at the corners Check for each block’s: Level, plumb, and alignment Checking horizontal spacing: Use a straightedge or four foot level

After 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 apart Use to ensure that the horizontal mortar jointing are running 3 /8 inches thick.

After first course of blocks
Key to a straight true wall: Using the mason’s line between the corners as a guide Most difficult part of laying blocks: Usually laying the closure block

After first course of blocks
Closure block: Last block laid to complete the row If 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)

After first course of blocks
Closure block: Must be buttered on both ends or Previously laid block must be buttered If mortar falls off the end of the block as swung into place, block should be removed and re-buttered

Tooling joints and removing smears
Completes job resulting in a professional appearance to the job

Tooling Joints Procedure that pushes the mortar into the groove between the blocks Creating an improved bond of the mortar to the block Results in a weather-tight joint with a neat appearance Jointer: Concave or V- shaped metal tool with a handle and turned up ends

Tooling 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

Removing mortar burrs After joints have been tooled, trim off with face of the wall with the trowel

Crooked Blocks Do not attempt to move or straighten the block once the mortar has stiffened or even partly stiffened

Mortar Dabs On block: Should be allowed to dry
Use trowel to knock dab off Piece of a concrete block to rub out remaining particles

Smears When laying blocks, be careful not to smear mortar into the blocks Once the smears are in the block it is impossible to remove them A wire brush will help but is unable to remove mortar from pores in the block Muriatic acid rinse will help clean the wall and make paint smears less noticeable

Review / 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.

The end!