AAC building systems have been successfully developed and implemented for 65 years. They have been used in residential and commercial applications.
This article will provide a detailed explanation of the installation steps for AAC blocks from a factory perspective. This article provides recommendations and guidance only; the installing contractor should determine specific operations.
Table of Content
There are a full range of tools that are specially designed to assist the block layer in installing AAC masonry products and increase productivity at the job site.
AAC masonry installation require the following masonry tools:
AAC Jumbo Block
Additional tools required for installing AAC jumbo masonry units.
AAC Masonry Products Leveling Course
Lay out wall lines on building slab by control lines.
Step 1 - Layout wall lines
At the highest corner of the slab place a full width 1/2" deep sand-cement mortar joint using a masonry trowel.
Do not use thin-bed mortar or large grain mortar for the leveling bed joint.
If moisture and wicking is a problem, add water resistance mixture to sand-cement mortar.
Step 2 - Start the leveling bed
Set the first corner block in the sand -cement mortar and adjust the joint as needed. To achieve the required height, lower or raise the block by tapping down with a rubber mallet or by adding additional mortar beneath.
Step 3 - Set the first corner block
Mix approved AAC thin-bed mortar in a clean mixing container (5-gallon bucket or pail) per manufacturer's directions. The consistency of the mixed thin-bed mortar should be such that it flows easily through the teeth of the notched trowel leaving the shape of the teeth in the mortar bed.
Thin-bed mortar droppings should not be used.
Step 4 - Mix thin-bed mortar
Set the second corner block adding thin-bed mortar to the head joint with the ¼ inch notched trowel.
Step 5 - Set second corner block
Repeat subsequent steps for each corner using a builder's level to maintain an equal elevation. Triple check each lead corner in all three planes.
Step 6 – Repeat for additional corners
After building the lead corners, pull a string between corners to complete the leveling course. Sand-cement mortar should be used for the bed joint and thin -bed mortar for each head joint. Level across each block to insure a plumb wall.
Do not use sand-cement mortar for courses other than the leveling course.
Step 7 - Fill-in completion of level course
Install lintels with a minimum 8" bearing (overlap) where required.
Lintels End bearing for lintels should normally be not less than 8". Where stresses under lintel bearing will exceed permissible values (e.g. under heavy concentrated loads), concrete spreaders or pad stones should be incorporated. Cold bridging at lintel positions can be avoided by the use of AAC in association with appropriate types of lintels. These allow the insulating properties of AAC blocks to be continuous across the wall face and can facilitate the placing of subsequent door and window fasteners. If multiple courses of U-Block are used, notching is required to allow concrete to get to the lowest course. Always pre-wet the u-block before pouring the grout.
Step 8 - Install lintels as required
Leveling course must be level and plumb. Do not proceed to subsequent courses until leveling course has set sufficiently
Blocks must be installed in a running bond with a 8" bearing (overlap). Lintels must be installed with a minimum 8" bearing (overlap).
All head and bed joints must be solid with approved AAC thin-bed mortar for full adhesion. Do not tooth.
Disclaimer: The information contained within this document shall be used as guidelines for workmanship and general construction practices for the installation of AAC Products. This information should be recognized as recommendations and should be used with judgment. Implementation, interpretation and use of this document shall be the sole responsibility of the Installation Contractor.