Swimming Pool Repair
As your gunite or concrete pool ages the plaster will require occasional repair. Cracking, hollow spots (sometimes called “pop-ups”), and chipping are common. As are wear spots in your pool plaster, where the plaster is worn away and the gunite is showing. Most of these pool plaster repairs can be done by yourself. With the right tools, the right materials, and a little know how, you can repair most cracks and chips without too much effort. The following is a step by step guide to making typical pool plaster repairs.
Swimming Pool Crack Repair
- Cut the crack out 1/2” deep and extend the length of the crack one inch on both ends. You will need a grinder or saw with a diamond blade. You can rent a 4” grinder, or buy one for about $50.00. Be sure to use all of the proper safety equipment (goggles, dust mask, ear protection) and safe operating procedures. What you are trying to do here is to simply widen the crack uniformly so that you can fill it with your repair plaster.
- Clear all dirt, dust, and loose plaster out and away from your cut. Be sure that no loose material remains where you will be applying your repair material.
- If your crack goes all the way through your pool’s shell: Apply a gun-grade caulk such as NP1 the length of the crack and fill the entire saw cut with caulk as well. Trowel the caulk even with the surrounding plaster. Allow the caulk to dry. Skip to step 8!
- Mix a premade pool patch such as EZ-Patch 1 with the supplied bonding agent and water. The mix should be the consistency of peanut butter. Add water slowly so that you don’t add too much. If this happens allow the mix to dry until it’s the right consistency.
- Lightly moisten the surface. With a flat trowel, putty knife, or your hands apply your pool patching mixture into the crack. Gently push the mix into the crack to make sure there is no air left in the gap.
- Smooth and even out the patch area with your trowel. Sponge the new patch to match the finish of the existing surface. Smoothing and blending the new plaster is much easier if you allow it to dry for 10 minutes before working with it. If the pool plaster repair won’t be under water for more than a few hours, cover it with a wet towel to keep it moist until the pool repair is covered with water to prevent the job from cracking.
Swimming Pool Plaster Repair
- Get your hammer and chisel and remove any loose plaster that is not bonded to the pool surface. Tap the pool floor with a hammer. You will be able to hear the hollow pool plaster. You can also feel the hollow spots if you walk over them. Chip or cut them out with a grinder or diamond saw. Be sure to use eye protection, gloves and all of the proper safety equipment.
- Chisel some divots and pock marks into the surface that will be patched to help your new plaster patch bond to the existing surface. Acid wash the surface to be repaired. Be sure to remove all debris and dust from the patch area.
- Mix up your pool patch acrylic bonding agent together with water. The mix should be the consistency of peanut butter. Add water slowly so that you don’t add too much. If this happens allow the mix to dry until it’s the right consistency. If the plaster is a custom color you can add masonry dye to the mix. Wet the surface of your original plaster before adding color to match – always match colors wet to wet.
- The best way to apply the mix is with a pool trowel. Wet the surface with your sponge or a fine mist.
- Apply the plaster mix with your trowel. Push the mixture into the corners and divots. Make sure you trowel it enough to there are no air bubbles left in the mixture. Trowel patch smooth. Wait 15 minutes and trowel the patch smooth again, you may need to sprinkle a little water around the edges to smooth it in with the existing plaster. Be sure to keep the pool repair moist until it is under water.
Fiberglass Pool Repairs
You can repair structural cracks in your fiberglass pool but it is a lot of work to make it look good. Most materials you need for this repair can be found at a marine supply store. Blisters and bubbles can be repaired the same way. Please remember, you may never get a perfect color match and it’s possible you will always see the repair. These repair steps are only for structural cracks. Spider-webbing of your fiberglass pool requires an entire resurfacing. These steps can also be used to repair fiberglass pool slides!
For best results, avoid doing your fiberglass repairs on very hot days and keep your repair area out of direct sunlight while you work.
You will need: Grinder; Drill; Random Orbit Polisher; Natural, Medium Softness, Tapered End Paint Brush, 4 oz. Fiberglass Sheet; 2-part Polyester Resin; 2-part Get Coat; Mixing Vessels; Mixing Sticks; Small Roller Tray; Small Felt Roller; Laminating Roller; Sanding Block; Wet Sanding Paper Grits 320, 400, 600, and 1200; Rubbing Compound; Polish; 2 Buffer Pads; Buffer Polish Pad; Acetone; Rags; Ammonia; Bucket. You may want a painter’s suit since fiberglass can cause skin irritation.
Before beginning, lower the water level of your pool to below the area needing repair.
- Grind down the entire area around the crack to remove the gel coat 2 inches out from either side of the crack to give your fiber glass sheets a surface to adhere to. Be sure to wear all the proper safety equipment. Goggles, gloves, and respirator.
- Drill a small hole at either end of the crack to stop it from getting longer.
- Grind down the crack (disc perpendicular to the crack) until you go through enough fiberglass to start expanding the crack's width. What you should have now is a slightly wider crack with tapered sides that thicken as you move away from the crack.
- Clean the area with a rag and acetone.
- Cut pieces of 4-oz fiberglass. Your first piece should be large enough to completely cover the area you grinded down. Each successive piece should be smaller than the last. You will be applying the fiber glass mat in this order, a process called feathering.
- Mix up polyester resin in an appropriate sized plastic container and pour it into a small roller tray. Using a felt roller, apply your first coat of resin to your repair area and apply the largest fiber glass piece. Saturate the mat with resin using the roller.
- Now use an "air roller", or "laminating roller," firmly press the fiberglass down and remove air bubbles from the resin.
- Repeat steps 6 and 7 using progressively smaller pieces of fiberglass until it is back to its original thickness.
- Let the fiberglass harden for 3 hours or so.
- Use 400 grit sandpaper on a sanding block to smooth and level the repair area. Once the repair is completely even with the surrounding fiberglass, wet sand the repair area with progressively finer grit sand paper (320, 400, 600, and 1200). To wet sand - Take a bucket and fill it with water and a small amount of ammonia, the ammonia acts as a lubricant. Wet the area you are sanding with this mix and wet your sanding block. Clean the area with a rag and acetone. If your fiberglass isn’t smooth your gel coat will not be smooth.
- Mix your gel coat with the hardener and pour the mix into another container for application (This removes the chance of accidentally getting un-catalyzed material onto your repair). Be sure to measure your hardener accurately. Too much or too little and your gel coat will not cure, cure too quickly, or it will look chalky.
- With a natural, medium softness, tapered end brush, apply a thick layer of gel coat to the repair area, intentionally going outside of the area onto the surrounding original gel coat. This will supply an area to blend in the new gel coat with the old. Let this first coat dry.
- Apply a second, thicker coat of gel coat in the same way as the first. Let the second coat dry. If your repair area is not in an area that can be seen or you simply do not care about the aesthetics of your repair you can stop after this step.
- Now you wet sand the repair with progressively finer grit sand paper (320, 400, 600, and 1200) on a sanding block. Using a light touch and orbital motions, sand over your repair area. This should remove all the brush marks and make the repaired area feel smoother than the original gel coat. Wipe off the sanded area with a rag and acetone. If you are using a colored gel coat you will see a lot of color on the rag, most of this color is from the new gel coat.
- Using an aggressive rubbing compound and a random orbit polisher at low speed, go over your repair area, do not press hard on the polisher or you may remove too much of your gel coat. Once you have done this wipe off the area with a soft cloth. Repeat this procedure with a polishing compound. Wipe off the area with a soft cloth and use a buffing foam pad to bring out the glossy finish of your repair.
Vinyl Liner Pool Repair and Patching
Most rips and tears in vinyl lined pools can be patched with a simple vinyl patch kit. Today, most pool vinyl patch kits can be used underwater or above the water level.
- Cut your vinyl patch material about 1/2” larger than the hole. Be sure to cut the vinyl patch material in a circle or oval so there are no corners on the patch. Corners peel off easily and the patch WILL come off.
- Clean the area around the hole to be patched. If the pool patch is a dry pool patch, use a little acetone (ex. nail polish remover) or a good vinyl cleaner.
- If you are patching dry, apply the vinyl glue to the area around the hole, and then the patch. If you are doing an underwater patch, apply the vinyl liner glue to the patch only, and fold it over on top of itself.
- Wait 3 minutes and press the patch onto the area being patched. Rub all of the air from under the patch, and take extra time to rub the edges all of the way around the patch.
- Wait 10 minutes, and rub the patch and edges again.