On In-ground gunite pools, the coping is the capstone for the beam, 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.
Beneath the pool coping, and behind the tile is what is referred to by pool builders as the bond beam, or just the beam. The pool bond beam is subject to many forces acting on it, and for this reason it is usually poured to be thicker and stronger than the lower section of the pool wall.
Beam damage could be defined simply as a crack that runs through the top of the pool wall. It may not be visible, until at an advanced stage, where cracking and crumbling of the tile is noticed.
Long, horizontal cracks in the pool tile are many times the end result of years of expansion and contraction of the concrete in a pool. If the expansion joint between the pool beam and the pool deck is not true, that is, does not extend through to the earth, then the pool and deck push against each other. Guess who wins? Usually the deck, with it’s lateral size, if pushing up against the beam, or built right on top of the beam (poor practice) will result in the top 6″ – 12″ of the pool wall cracking and separating.
The repair to a broken bond beam is pretty involved. Remove all the coping, all the tile and chip down to solid beam. Remove all debris. Form and pour hydraulic cement, using steel rebar plugs wired together to create the new beam. Strip the forms, and set new tile and coping and caulking between a true expansion joint.
This can be a major repair, if the entire pool has to be done. Partial repairs can be done, if a matching tile and coping can be found (sometimes this is difficult).
Bond Beam Repair:
Typical costs for beam repair run an average $65 per linear foot. A vertical pricing structure is sometimes used, depending on the depth of the crack. If the crack is higher up on the tile the job is cheaper. If the crack goes lower, or even beneath the tile, prices are higher.