How to Use Pool Caulking
It used to be that all pools built had the expansion joint between the perimeter coping and the pool deck caulked, that is, filled with elastomeric sealant, 30 days after the concrete was poured. This was holding up the checks to the builders, I was told, so they sort of stopped mentioning it.
It is well worth mentioning. The expansion joint is an important interface between the pool and the deck. These two independent structures need to remain independent. Keeping debris out of the joint ensures that the joint is “true” and the two structures are not in contact with each other. When they do come in contact, the pool may develop a crack in the tile, which is usually an indication that the “beam” has cracked all the way through. The beam is defined as the top 6 or 8 inches of the pool wall which holds the tile and coping. Beam damage gets worse with time, eventually crumbling, requiring beam reconstruction. To avoid this costly expense, caulk your pool expansion joint! Pool caulking also keeps out water which can freeze and expand. This can damage the coping, beam and eventually, the tile.
A good pool caulking job starts with good surface prep. The sides of the joint must be clean, dry, rough and solid. Backer rod foam should be placed in the joint (don’t use sand) to give the pool caulking something to sit on top of. The joint is taped off to keep things neat, and pool caulk is shot or troweled into the joint to a depth of 3/8-1/2″. The pool caulk should be an elastomeric sealant, suitable for outdoor use. Deck-o-Seal pool caulking and Vulkem pool caulking are two popular brand names. Self Leveling pool caulk is kind of runny and it seeks a level. Gun Grade type of pool caulk is thicker, like bathroom caulk, and a small trowel or float is used to level it out. Both types are sold in tubes that fit into a standard caulking gun. Tape is removed before caulk sets. Replace or repair pool caulking if it cracks or pulls away from either the deck side or the coping side.
Prices for professional expansion joint caulking run $3.50-5.00 per linear foot. Add up the perimeter of the pool to figure your price. The variance depends on the width of the joint, which is usually 1/2″-1″ or regional diferences. Price includes full prep, backer rod, pool caulking and finishing.