Pool Info: Pool Coping Repair
Pool coping is the capstone for the beam, or the top of the pool wall, and is used to finish the pools edge and bring it up flush with the pool deck. Pre-cast concrete coping with a bull-nose front edge has been the standard for many years. Modern designs are making use of bull-nose brick coping in many colors and textures. Flagstone is also a popular choice, without a safety grip edge.
The pool without coping has been accomplished with the cantilever deck. Inspired by Frank Lloyd Wright's designs, the cantilever pool deck extends over the edge of the pool, and is free-floating. Cantilever decks do not require caulking of an expansion joint, because there is none. The pool deck floats over the pool, rather than being next to, or side by side, as is normally done.
Vinyl liner pools have their coping attached to the wall, usually C-shaped, such that the pool deck is poured into the coping, but installing stone coping or a cantilever pool deck is also possible on a vinyl pool. Replacing vinyl liner pool coping is a difficult job when it’s attached to the pool wall and the deck is poured right up to it.
Loose coping stones?
First question to be asked is "have you caulked your expansion joint?" Freezing water in the joint will put pressure on the coping, breaking the mortar that attaches it to the beam. Second question will be "Is the expansion joint true, or does the pool deck touch the coping?" When they cannot expand independently without hitting each other, it pushes on the coping (and the beam) every time the deck or the pool expands in warm temperatures. If the stone is just barely moving, there’s little concern, but a loose stone should be repaired.
Crumbling mortar joints between coping stones?
If there is only a small check crack, it's probably not a problem. Cracking large enough to allow water to seep in will create havoc. We also want to note the possible reasons for this mortar joint to be crumbling. It could be just chemical breakdown or a bad mix, or there could be a directional force applying pressure to the area. Chip out loose material, clean well and fill with a sanded grout of a similar color. Mixing with a bonding additive liquid is a good idea.
Material above tile missing?
Looking at the coping from the pool side, there is usually a strip of pool plaster above the tile, and below the coping, or a grout joint in between the two. This is often thinly applied and can fall out with movement or ice issues. Use a pool plaster mix, or waterproof tile grout to repair the area, after chipping and cleaning. After mixing, push the material in with a putty knife, roughly smoothing. After 20-30 minutes, you can clean it up with a wet sponge or rag. Let it dry overnight and clean again the next day, to wipe the haze off the tiles. Use a bonding additive for best results.
Resetting loose coping stones?
If the coping stone has become loose, to the point where it wobbles when you stand on it, it could become a safety issue. To reset coping stones, use a chisel and hammer to pull up the stone, and chip off any mortar from the sides and bottom. Then chip out and score the mortar bed that sits on top of the beam. Clean it well and moisten with water. Mix up a thin set mortar (unless you removed all of the previous mortar bed, then use medium based mortar), and spread it over the surface. Press the stone into place, and use a large rubber mallet to set the stone in place. Once dry, mix up a sanded grout made for outdoors to place in the joints on each side of the coping stone.
Typical costs for removal and replacement of pre-cast pool coping average $25 per linear foot. Prices rise for bull-nose brick, and more for flagstone coping. To replace all of the pool coping is quite a job, and not DIY friendly. Professional pool masons use air powered chisels and small jackhammers and diamond blade grinders to carefully pull up all of the loose stones. When all the stone is removed, the mud bed of the previous mortar is mostly removed, to allow for a new bed of mortar to be laid, without raising the level of the coping stones in relation to the pool deck.
When replacing or resetting a few coping stones, bear in mind that new coping stones will be a slightly different hue than the old stones next to it. When replacing coping stones, the old stones are usually destroyed during removal. It is difficult to re-use coping stones because many break when coming up or when cleaning the undersides. For this reason, many people with several, but not all bad stones, will replace all anyway, especially if they're changing styles or colors.
Cleaning pool coping stones:
Coping stones will get dirty, especially the white precast stones. To clean coping stones, you can use a pressure washer. You can also pour a weak acid solution over the stones, or a weak bleach solution (but not both together!), over the coping stones for stain removal. Always add chemical to water, not water to chemical. Carefully pour 1 part acid (or bleach) into a flower watering can or bucket. Wet the surface first, and then carefully pour the mixture slowly and accurately. Run over it with an acid brush or stiff push broom. Rinse completely within 30-60 seconds of pouring the solution.
Painting pool coping stones:
You can paint pool coping stones, but keep in mind that the paint will eventually fade, or possibly blister and peel, and may need to be reapplied every few years. Pool deck coatings are more durable when used on pools in dry, arid regions, than in humid, wooded areas or northern pools that winterize. Cleaning with acid, essentially acid washing the stones is usually a better way to refurbish coping stones. However, if you want to paint the stones, you can with pool deck and patio paints, even painting the deck the same color.