Since the gunite pool is constructed in part by spraying concrete onto steel mesh forms, it can suffer damage to its structure when heavy objects fall into the pool. Cracks may appear in the pool shell due to shifting of one section of the formwork relative to another. A small crack in a gunite pool formed because of this type of damage is not a serious problem. Repairing the crack is not necessary to keep the concrete strong enough to support the pool's weight, especially if pool water is kept out of the crack during use.
Any damage that results in an opening in the gunite shell larger than 1/4 inch should be repaired to prevent the entry of water into the pool. If water does get in, the steel reinforcing bars in the concrete will rust. This would weaken the structure of the pool and could cause its collapse. Patches can be used to cover large openings until permanent repairs are made. Click here to learn more. Every pool has the potential to crack. If it's not closed, you can pretty much assume that there's some small hairline crack in it somewhere. The question is whether or not this little hairline crack poses any sort of threat to the integrity of your pool shell. A professional gunite pool company such as Swim Care Pool Services can quickly fix cracks on your pool wall by installing a patch. The experts can ensure that your pool's water doesn't leak out of the cracks.
Repairing a crack on a gunite pool can be a bit more difficult than repairing a crack in a vinyl or fiberglass pool because it requires removing some of the surrounding material from around the deep end of the pool to create enough room to be able to drill into the area surrounding the crack, remove the defective gunite and then put in a patch. The process can take several hours but is important if you don't want water leaking out of the pool through the cracks. A professional pool company has all of its tools with them, including jackhammers that they use for this but if you want to DIY here are some tips you could follow.
1. Stop the water from entering the crack by covering it with a piece of non-corroding plastic, such as a section of plastic drop cloth or a garbage bag. The cover should be large enough to extend several inches past each side of the damage and be held in place around its edges by calking compound or sealant.
2. Mix patching compound according to the manufacturer's instructions for handling and applying it. Calking compound may be mixed with sand, but should not be mixed with other materials that can alter its consistency or performance.
3. Apply a 1/4-inch layer of the mixture to repair the crack in the gunite pool shell. Fill the crack completely, but avoid covering the plastic patch.
4. Remove excess compound from around the outside of the repair area with a trowel or putty knife. If you do not remove enough material, it might prevent you from making an effective seal with the next layer of patching material. Allow this first application to dry overnight before applying a second layer.
5. Mix another batch of compound if necessary, and apply a 1/4-inch thick second layer over the first one. Smooth this application with the trowel or putty knife to create a smooth surface that does not contain lumps or other imperfections. Allow it to dry overnight before testing for water leaks by submerging the repaired area underwater.
6. Remove the plastic patching material after the pool shell is dry and before filling it with water. If leaks are detected, repeat steps 4 through 6 until the pool holds enough water without leaking.
7. Fill the pool with water and test it for leaks before using it for swimming or other recreational water activities.
8. Inspect the pool structure for other damage that might require repair.
Repairing a crack in the gunite shell of a swimming pool is not difficult as long as you follow all safety procedures and adhere to guidelines for mixing, applying and patching the material used to seal it. Repair any large cracks before they expand or if water has already leaked into the pool.
If the crack is in an area above water, it can be sealed with a specialized epoxy formulated to bond to concrete. This product contains rubber particles that expand when exposed to water to form a tight seal. Such products are available at many hardware or home improvement stores. Be sure to follow all manufacturer's directions for using the product to get the best results.