Floor Slab Isolation Joint

Some proprietary joints come with removable caps to form this sealant reservoir.

Floor slab isolation joint.

Also the floor and the wall usually shrink at different rates and the difference in amount of shrinkage is likely to cause the floor or wall to crack if they interlock. Isolation joint material should go all the way through the slab starting at the subbase but should not extend above the top. Concrete isolation joints or expansion joints separate or isolate the concrete from other parts of the building structure like walls footings columns and piers. Isolation joints are generally formed by casting against a compressible preformed filler material eg self expanding cork over the full depth of the joint to provide a complete separation.

For a cleaner looking isolation joint the top part of the preformed filler can be cut off and the space filled with elastomeric sealant. The joint free slab. Isolation joints also sometimes functioning as expansion joints. Maximum joint spacing should be 24 to 36 times the thickness of the slab.

A concrete expansion joint is also used to separate a concrete driveway or patio from a garage slab sidewalk stairway light pole or any other point or restraint. The idea is to reduce restraint so your slab doesn t crack. Most details we ve seen recommend not placing the slab directly on the footing but if you ve got enough vertical clearance we think a inch layer of sand would work better than isolation joint material. What is the difference between a contraction joint isolation joint expansion joint construction joint and a cold joint.

The perimeter joint prevents this problem. Saw cut joints should be done within 4 to 12 hours after the concrete has been finished. A contraction joint is formed sawed or tooled groove in a concrete structure to create a weakened plane to regulate the location of cracking resulting from the dimensional change of different parts of the structure. Expansion joints which are really isolation joints permit differential settlement of the wall and the floor.

Isolation joint material should go all the way through the slab starting at the subbase but should not extend above the top. Joints should be spaced about 10 feet and a maximum of 15 feet. Some proprietary joints come with removable caps to form this sealant reservoir. For a cleaner looking isolation joint the top part of the preformed filler can be cut off and the space filled with elastomeric sealant.

And rectangular dowels and for diamond shaped load plates are provided in aci 302 1r 04 guide for concrete floor and slab construction or aci 360r 06 design of slabs on ground. When using joint groove for contraction joints the joint should be a minimum depth of thickness of the slab. Joints are commonly spaced at distances equal to 24 to 30 times the slab thickness. If you don t have the clearance a layer of 30 pound roofing felt should work.

Joint spacing in feet contraction joints may be tooled into the concrete surface at the time of placement.