How to Repair & Seal Expansion Joints in Concrete

How to Repair & Seal Expansion Joints in Concrete


Repairing and Sealing Horizontal and Vertical Expansion Joints. Concrete Expansion Joints are cuts in concrete
slabs that go completely through the slab to the base material. Expansion joints
can also be the joints between walls and concrete slabs. The purpose of an
expansion joint is to allow the concrete slab to expand and contract with
temperature changes…without cracking the slab. Concrete expansion joints must be sealed
with a flexible sealant or an expansion joint strip, to prevent water from
penetrating the joint and deteriorating the sub base. As with any concrete repair, proper
attention to joint preparation is essential to achieving a successful
result. Expansion joints should be swept out to ensure that any pebbles, dirt or
loose debris are removed. If oil or grease are present, QUIKRETE Concrete and Asphalt
Cleaner should be used so that a strong bond can be made between the sealant and
the edges of the joint. Before applying a sealant, the joint must be completely dry. The best option for sealing horizontal
expansion joints is QUIKRETE Self-Leveling Polyurethane Sealer.
Self-Leveling Polyurethane Sealant is a highly fluid and flexible sealant that will
stretch up to 800 percent without failing. This allows for ground
movement and expansion and contraction from temperature change. For joints over
1/4 inch, Backer Rod, which is a foam rope, should be placed in the
expansion joint before applying the sealant. The Backer Rod should be
pressed into the joint allowing a sealant depth of between 1/8 inch and
1/2 inch. Polyurethane sealants work best when they are bonded only to the
inside edges of the crack or joint. Always wear eye protection and
waterproof gloves when working with polyurethane sealants, and work in a
well-ventilated area. To apply Self-Leveling Polyurethane Sealant, first
cut the tip of the nozzle at an angle with a utility knife, matching the
width of the crack, and insert the tube into a standard caulk gun. Move the nozzle slowly along the length
of the joint, allowing the sealant to settle. Self-Leveling Sealant is highly
fluid and may require an additional application. This should be done
immediately so that the two applications will mend
into each other. No additional tooling is necessary. QUIKRETE Self-Leveling
Polyurethane Sealant will be tack-free in two hours and will dry to a smooth gray
finish. Excess sealant should be cleaned up immediately with a commercial solvent or a citrus based cleaner. Polyurethane Sealants are temperature sensitive and
should not be used when temperatures are below 50 degrees. For vertical expansion
joints in concrete, masonry or stucco walls, the best option for joints over
1/4 inch wide is QUIKRETE Non-Sag Polyurethane Sealant. Non-Sag
Polyurethane Sealant is a multi-purpose permanently flexible sealant that seals and
waterproofs vertical joints. For joints over 1/2 inch, Backer Rod should be
placed in the joint before applying the sealant. The Backer Rod should be
pressed into the joint, allowing a sealant depth of between 1/8 inch and
1/2 inch. To apply Non-Sag Polyurethane Sealant, first cut the tip of the nozzle
at an angle with a utility knife… matching the width of the crack…and
insert the tube into a standard caulk gun. Move the nozzle slowly along the
length of the joint, pressing the sealant into the joint. The tip of the nozzle can
be used to smooth the sealant. QUIKRETE Non-Sag Polyurethane Sealant will be
tack-free in about two hours and will dry to a smooth gray finish. Excess sealant
should be cleaned up immediately with a commercial solvent or a citrus based cleaner.
Polyurethane Sealants are temperature sensitive and should not be used when
temperatures are below 50 degrees.

Leave a Reply

Your email address will not be published. Required fields are marked *