Full Answer
What to consider when sealing concrete joints?
Things to consider when sealing or filling concrete joints. Sealers must bond to the concrete and be impermeable. Courts and Cracks. Sealed joints should have a backer rod or bond breaker in the bottom. Sealers and fillers for concrete joints are not the same thing and have very different purposes. While it's not always necessary to seal ...
What is the best way to seal concrete?
Effective sealant materials must bond to the concrete, be impermeable, and be able to handle the expansion and contraction. Before installing a sealant, the joint must be dry and free of dust and debris. Vacuum it thoroughly before sealing. Carefully follow the sealant manufacturer's installation instructions. ...
What is a sealer for concrete?
A sealer is soft and able to accommodate the concrete slab's expansion and contraction. The sealer's purpose is to prevent water, ice, and dirt from getting into the joint (and into the subgrade) and to prevent intrusion from below the slab—including of radon. Sealers can also improve the appearance of floors and slabs.
What is a filler in a saw cut joint?
A filler is a rigid material that supports the edge of the joint when heavy traffic crosses, like this polyurea joint filler from Specguard. This type of material is only effective with saw-cut joints; rounded tooled edges can't support the filler.
Where to use a sealer rod?
For sealers, use a bond breaker or backer rod in the bottom of the joint. This prevents the sealer from sagging into the joint and from adhering to the bottom of the joint, which allows the sealant to stretch on both the top and the bottom. A backer rod in the joint also keeps the sealer plug thinner, reducing the amount of sealant needed.
How long does it take for concrete filler to work?
Fillers are only effective if installed after the concrete has gone through most of its shrinkage, although that can take a year or more. Fillers and sealers should be checked at the end of the first year of service and repaired or replaced as needed.
What is expanding polyurethane foam used for?
In the past, expanding polyurethane foams were used to fill the gap between precast units and in concrete slabs. We’ve found that the foam rods are much quicker and easier to apply and work better with the movement in the walls.
Do you need to prep concrete joints before sealing?
It’s important to know that concrete joints need to be prepped before you seal them – there are two products that you’ll need for this: The concrete primer will ensure that the sealant will bond properly to the concrete and the foam backing rod will reduce the amount of sealant needed.
What does a concrete joint sealer do?
When it comes to concrete floors a concrete joint sealer will protect the joint from damage caused by heavy equipment being driven and/or rolled over the expansion joint, chipping and cracking the edges, which eventually leads to concrete joint failure .
What is the purpose of sealing concrete joints?
Using concrete joint sealant to seal concrete expansion joints and concrete contraction joints in concrete floors and concrete walls is an important part of maintaining the integrity of the concrete.
How is concrete seal made?
They are produced by partially filling the cells of high quality cellular polyurethane foam with non-drying, water-repelling adhesive agents. The combination of this impregnation treatment followed by compression of the fully expanded material to as much as one-fifth of its size, creates a concrete sealant material that, when installed in a joint, is always in compression.
What is concrete hybrid sealant?
With concrete hybrid joint sealants, the opening and closing movement of a joint gap results in the surface sealant folding and unfolding, rather than stretching an compressing. This eliminates the substrate bond line stresses and failure or composition changes caused by pre-cure joint gap movements.
What is liquid joint sealant?
LIQUID SEALANTS - Liquid joint sealants for concrete are mostly used because of the relatively low material cost and ease of installation. High performance silicone sealants provide moisture impermeability, low modulus, UV resistance, and retain these physical properties with changesin age and temperature.
What is impregnated foam sealant?
Impregnated foam sealants, by virtue of their depth, density, and adhesive infused cellular composition, also resist air pressure differentials often found between interiors and exteriors of buildings using forced air heating and cooling systems.
What is the best way to prevent sealer from sagging?
To prevent the sealer from sagging into floor joints or reducing the amount of sealant needed in wide gaps in wall joints, a foam backing rod can be used.
Why do you seal precast concrete?
How To Seal Precast Concrete Joints. The main reason for applying mastic to the joints of precast concrete is to create an impermeable barrier between the units, this could be for preventing dirt and water getting into a construction joint or to make a weatherproof seal – Sealants can also improve the aesthetics of the wall giving ...
Why use mastic instead of mortar?
The benefits of using mastic rather than mortar are that the mastic will remain soft and be able to deal with movement between the precast units. It will also cope with expansion and contraction of concrete joints if being used for floors. Mastics are supplied in 380ml tubes or 600ml sausages and are applied using a mastic or caulking gun.
What is the benefit of mastics on concrete?
The Benefits of Elastic Joint Sealants. Flexible mastics will move with the concrete joint and increase the life-span of the seal. They will adhere to the precast concrete to ensure the joint remains sealed at all times. Mastic is easy to apply without the need for specialist equipment or training. The mastic application is fast and cost-effective.
Why do you apply primer before sealing joints?
The application of the primer before sealing the joints will ensure maximum adhesion to the concrete and enhance the life-span of the product.
How to prepare a sealant tube?
Prepare the sealant tube/sausage by attaching the application nozzle to the tube or cut the end of the sausage. If using a mastic tube, cut the nozzle to the required size to enable enough mastic to flow in one movement to fill the joint.
How to apply mastic to a joint?
Starting at one end of the joint, apply the mastic using even pressure on the mastic gun or adjust the flow rate of powered mastic to the desired amount.
