Definitions of terms associated with concrete masonry units A.Masonry Units: Blocks made from concrete, cinders, or other aggregates. B.Laying Block: The process of mixing mortar, applying it to masonry block, and placing the block to create walls. C.Mortar Bed: A layer of mortar. D.Core: The hollow space in a masonry block. E.Corner Pole: A straight piece of wood or metal held plumb by diagonal supports. F.Course: A row of masonry units. G.Brick Set: Wide chisel used for breaking masonry units. H.Hollow Core Block: Masonry block with two or three holes per block. I.Masonry: Anything constructed of brick, stone, tile, or concrete unit held in place with portland concrete. J.Lintels: Steel reinforced- concrete beams used for support over windows and doors. K.Mortar Board: Board used to hold mortar. L.Concrete Sills: Used under windows and doors. M.Footer or Footing: A continuous slab of concrete which provides a solid, level foundation for block or brick

Types of Blocks A.Stretcher: Used in straight wall sections. B.Corner: One flat end to create attractive walls at corners. C.Sash: Has special grooves, can be laid to receive window. D.Jamb: Use to make door ways so the openings are attractive and secure. E.Half: Used to prevent cutting of blocks when only half a block is needed. F.L-Block: Used as top course of block on a poured floor.

Estimating Block A.Standard blocks are 8 inches or 2/3 foot high and 16 inches or 1 1/3 foot long when they are laid with a 3/8 inch mortar joint. B.One foot is 3/4 the length of one block, therefore, when estimating the number of blocks needed for a job, the length of the wall in feet can be multiplied by 3/4; this gives the number of blocks per course. C.One foot is 3/2 of the height of a block, therefore, the height of the wall in feet can be multiplied by 3/2 to determine the number of courses needed.

Procedure for laying blocks A.Spread a layer of mortar called a mortar bed as the footer. B.Position the block on the mortar bed so that its outside corner rests where the outside corner of the wall should be. Level the block by first placing the level across the block and then lengthwise along the block. C.Turn several stretcher blocks on end and apply mortar to the ears with a wiping or swiping stroke of the trowel. D.Lay several stretcher blocks in place by working away from the end or corner block. E.Use the end of the trowel handle to tap the block until each block is plumb, level, and the course is straight. F.Apply a mortar bed on top of the first course in preparation for the second course. G.If extra strength is needed in the wall, install reinforcement in the mortar bed.

Procedure for laying blocks H.As the block laying progresses, cut off excess mortar with the trowel. I.Use a line to keep the courses straight. The line is positioned to be level along the top of the block. J.When a block must be cut, use a mason=s hammer and make multiple strikes along the line to cut; then make one sharp strike on the web. K.Check the height to be sure each new course is an additional 8 inches high. L.After the mortar dries and hardens slightly, finish the joints by rubbing it with a broken piece of block. M.If a joint other than a flush joint is desired, use a jointer to compress the mortar and create a watertight joint. Tools are available to create joints that are concave, v-shape, flush or raked.

Common concrete blocks used in building construction

Notes:1.Door openings will have 2" jambs on both sides and top. 2.Door will be a standard height (44" x 6'8"). 3.Door sill will accommodate a concrete floor inside. 4.Window openings will accommodate standard size windows. 5.Space above the top of the door will accommodate appropriate trim under the eaves of the roof. 6.Reinforced concrete lintels carry the weight over door and window openings. 7.There are no cut block in the wall. Therefore, the wall can be built with a minimum of cost and labor. A building front laid out using only whole and half block.

Illustrating common method of picking up and setting concrete blocks

Placement of corner poles for constructing a block wall

Showing procedure in laying concrete block walls

The usual practice in applying mortar to concrete blocks

A method of laying concrete blocks. Good workmanship requires straight courses with the face of the wall plumb and true.

Showing detail of joining an interior and exterior wall in concrete block construction.

8" x 8" x 16" Concrete Block Corner in the Running Bond

Plan View of First Course Layout typical 3/8" joint 8" x 8" 16" block

Types of joint finishes used on block walls Concave jointV-Joint Flush Joint Raked Joint