Floor Slab Isolation Joint

Isolation joints also sometimes functioning as expansion joints.

Floor slab isolation joint. 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. Joint spacing in feet contraction joints may be tooled into the concrete surface at the time of placement. The perimeter joint prevents this problem. Isolation joint material should go all the way through the slab starting at the subbase but should not extend above the top.

Saw cut joints should be done within 4 to 12 hours after the concrete has been finished. Some proprietary joints come with removable caps to form this sealant reservoir. 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. What is the difference between a contraction joint isolation joint expansion joint construction joint and a cold joint.

The joint free slab. If you don t have the clearance a layer of 30 pound roofing felt should work. 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. When using joint groove for contraction joints the joint should be a minimum depth of thickness of the slab.

Joint spacing in meters. 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. Concrete isolation joints or expansion joints separate or isolate the concrete from other parts of the building structure like walls footings columns and piers. Maximum joint spacing should be 24 to 36 times the thickness of the slab.

Some proprietary joints come with removable caps to form this sealant reservoir. Expansion joints which are really isolation joints permit differential settlement of the wall and the floor. Joint spacing that is greater than 15 feet require the use of load transfer devices dowels or diamond plates. 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.

The idea is to reduce restraint so your slab doesn t crack. Joints are commonly spaced at distances equal to 24 to 30 times the slab thickness. For a cleaner looking isolation joint the top part of the preformed filler can be cut off and the space filled with elastomeric sealant. Expansion joints are used in pavements to provide for thermal and moisture induced movement of the slab.

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.