How to Caulk a Pool Expansion Joint

What You'll Need
Polyurethane foam/rod
Caulking compound
Cloth and brush
Caulking gun

The pool expansion joint is an important line between the pool deck and the coping stones. They are usually filled with caulks that enable free movement of the pool deck without cracking. Pool expansion joints are crucial to prevent contact between the pool and the deck, which could crack if the two structures come in contact with each other. Caulking can prevent water from seeping inside small gaps. If water from leaks pools behind the coping and the tile band and freezes, it can damage them. Follow these steps if you want to caulk a pool expansion joint.

Step 1 – Choose the Caulking Material

Select a caulking material depending upon your needs. There are fire resistant caulks, polyurethane caulks, moisture cured caulks, high and low strength caulks. Determine your requirements and select accordingly. Water based silicone caulk is ideal for use in a swimming pool. Silicone caulk is very flexible and watertight. It is also very hard-wearing and resistant to fungus and moisture growth. Silicone tends to dry very quickly, so you’ll have to be quick while applying it.

Step 2 – Prepare the Surface

The work of caulking the pool expansion joints starts with a good surface preparation. Start cleaning the expansion joints with a cloth or scrub them carefully with a hard brush to remove any stains from previous compound treatment, water resistant gels and grease. Clean the glass or metal surfaces with a toluene compound. The joints should be rough, clean, dry and solid. Ensure that the joints are dry before you pour the caulking. The caulking will not bond well of the surface is wet. Do not leave the joint without drying if it contains moisture. Clean it properly.

Step 3 – Fill the Joints

Start filling the joints with polyurethane rod or polyurethane foam available at a hardware store. This will give the caulk the support and a base to sit on perfectly.

Step 4 – Apply the Caulk

Purchase a caulking gun for easy application. Fill the gun with the caulking product and shoot the caulk into the joint to a depth of 3/8 to 1/2 inch. You can also spread the caulk using a trowel if the joints are large. Ensure that the caulk you use is an elastomeric sealant which is suitable for outdoor use.

Step 6 – Check for Wear and Tear

Remove the tape before the caulk sets. Reapply the caulk yearly if it shows signs of wear and tear or if the joints expand more.