How to Waterproof an Old Swimming Pool?
An old swimming pool water can leak into the groundwater in the dry season, and groundwater seep into the pool in the rainy season. This can happen due to cracking, wearing, tearing and peeling the waterproof layer in the pool. In order to prevent this severe problem, you should waterproof an old swimming pool surface by following these important steps
You should observe the pool leaking before waterproofing. When you see water decolorization, water level changing, stain marks, mud, and odor in the pool water, you should re-apply the waterproofing layer on the pool surface again. Then you should drain the pool. You can fix small cracks in the used pool using EpoxyBond Pool Putty. Larger pool dmages should be fixed after drain the water.
After the pool drains, you should clean the empty and dried pool to remove leaf litter, sand and other debris. Then, you should wash the pool and remove all the caps, lights and fittings. Then, you should clean the pool surface using a heavy-duty cleaner such as TSP. Rinse all the TSP on the surface and start to fill the cracks using epoxy filler. Cracks should be cleaned before filling by devoting "V" shape. Then, fill the groves using epoxy filler and sand.
After curing the filler, you should sand the pool surface. After sanding, you should wash the pool surface using a commercial HCL dilution. After the HCL cleaning, you should use a bicarbonate solution to neutralize the acid reaction. If you fail to neutralize the acid reaction, you can see paint peeling and adhesive failing the coatings.
After rinsing the bicarbonate solution, keep the layer dry thoroughly. Then you should apply the primer and waterproofing membrane on the surface. You can use spreading tools for this task. After waterproofing and reapplying, let the surface to dry for 24 hours. Always follow the recommended environmental conditions for optimum performance.
What are the Tools and Materials for Waterproofing an Old Swimming Pool?
You should use the below tools and materials for waterproofing an old swimming pool.
Tools and instruments for waterproofing an old swimming pool
- Non-slip shoes
- Broom
- Mop
- Dust pad
- Pressure washer
- Roller
- Sprayer
- Buckets
- Brush
- 20-40grit sandpaper
- Masonry cutting blade
- Trowel, Spectular
- Grinder
- Submersible pump
Materials and products for waterproofing an old swimming pool
- EpoxyBond Pool Putty
- TSP (Trisodium Phosphate)
- Commercial HCL
What are the 8 Steps for Old Swimming Pool Waterproofing?
You should follow the below 8 steps for old swimming pool waterproofing.
- Observe for Swimming Pool Leaking
- Drain the Pool Water
- Clean the Swimming Pool
- Wash the Surface Using Heavy Duty Cleaner
- Fill the Cracks Using Epoxy Filler
- Sanding the Pool Surface
- Wash the Pool Surface Using Acidic Water
- Apply a Waterproofing Layer
1. Observe for Swimming Pool Leaking
First, you should make sure whether the swimming pool water is leaking to the ground or groundwater seeping into the swimming pool. You should observe the below signs that can cause pool leaking.
Swimmingpool waterlekaing signs
- Decolorization of water
- Water level changing
- Stain marks on the pool
- Mud in the pool
- Odor in the pool water
- pH level changing
- Chlorine level changing.
After you observe one or a few of these signs, you have to waterproof the old pool again.
2. Drain the Pool Water
When you observe water leaking signs in the pool, you should decide whether waterproofing can be done with water or after draining the pool because you do not need to drain the pool to fix the minor cracks in the pool. You can use EpoxyBond Pool Putty to seal the cracks in the pool with water.
But you should drain the pool to fix severe damage to the pool surface. After draining the swimming pool, keep it for dry few days.
3. Clean the Swimming Pool
After drying the empty pool you should clean it by using a broom to remove leaf litter, sand and other debris in the pool. You can observe cracks, holes, paint peeling, blistering, abrasions and seam and joint damage while you are cleaning. Note down the damages for future fixing.
- Then you should wash the pool surfaces using water. You should use a submersible pump to remove the pooled water.
- After the cleaning is done, you should remove all the caps, lights and fittings before starting the waterproofing process.
4. Wash the Surface Using Heavy Duty Cleaner
After the cleaning process, you should wash the pool using a heavy-duty cleaner to remove heavy deposits of grease, grime, stain marks, challked paint on the surface. In this step, you can use TSP (Trisodium Phosphate).
When you wash the pool using TSP, do not let the TSP to dry on the pool surface before rinsing with the water. You can use water to rinse the TSP on the pool surface.
5. Fill the Cracks Using Epoxy Filler
After heavy-duty washing, you should fill the cracks using an epoxy filler. After washing, you can observe the cracks and divots on the surface.
You should fill small divots that have a depth of less than 10 mm and small cracks that have a width of less than 5 mm.
You should use sanded cement mix if the divots are deeper than 10 mm
Small cracks should be opened up into the “V” shape up to the base of the crack. You can use an angle grinder with a masonry cutting disc.
Then you should fill the cutting path using epoxy filler. When you mix the epoxy filler, you should mix a small amount of filler that can be used within 30- 40 minutes.
Hairline cracks should not be filled with epoxy filler. Those can be filled with the coatings.
6. Sanding the Pool Surface
After curing the filler after 24 hours, you should sand the whole surface using 20-40 grit sandpaper. It will remove the old waterproofing membrane on the surface and increase the adhesiveness of the layer.
After the sanding, you should remove all the dust and residue particles using a broom and then rinse the pool again to remove all the remaining dust in the pool after sanding. In the end, you should wash again using a washer pressure before applying the prime coat on the surface.
7. Wash the Pool Surface Using Acidic Water
After pressure washing, you should clean the pool surface using a commercial HCL Hydroclolic) acidic dilution. You should mix the acidic solution as below proportion.
| Surface | Acid Parts | Water Part |
| New cement render | 1 | 2 |
| Old cement render | 1 | 3 |
| Marblesheen Sound and Hard | Concentrated acid | None |
| Marblesheen Sound and Soft | 1 | 1 |
You should not add water to acid. You should add the acid to the water.
Do not overfill the acidic solution. You should apply the acidic solution on the surface using a plastic watering can.
Wash the pool surface using fresh water after 5 minutes after the bubbling reaction stops.
Rinse all the equipment using fresh water to protect them from the acids.
Then you should apply the bicarbonate solution to neutralize the acid reaction. If you fail to neutralize the acid reaction, you can see paint peeling and adhesive failing the coatings.
Use a broom to apply the bicarbonate solution on the pool surface.
Rinse the pool surface again using fresh water.
After the washing process, allow the surface to dry thoroughly.
8. Apply a Waterproofing Layer
After drying the pool surface, you can apply a selected waterproofing coating on the surface. You can use polyurethane, epoxy, and silicone-based sealants as the waterproofing membrane on the pools. All of the membranes should be mixed and spread on the surface according to the manufacturer's guidelines.
When you use epoxy as the coating, you should mix the base of the epoxy and the hardener of the epoxy 1:1 proportion. If you mix them insufficiently, the coating will not cure effectively.
Pool surface temperature between 10 °C - 30 °C. If the the shell temperature is varied higher range, it can affect the waterproof performance of the pool.
The best time to apply the membrane on the surface is between 8 am to 11 am to optimise the performance.
Measure the area and apply the necessary coating on it. It will help to maintain the uniformness of the layer.
Use a brush or roller to apply the epoxy coating on the pool surface. After applying keep the layer for curing 24 hours.
Then apply the second coating according to the manufacturer's guidelines. Then keep it for drying as per the manufacturer's instruction before filling the pool.
After filling, you should not add chemicals other than salt or chlorine for at least 3 - 5 days.
How to Damage an Old Waterproof Swimming Pool?
An old waterproof swimming pool can be damaged due to
- Allowing heavy objects in the pool - Dropping heavy objects into the pool can wear and tear the pool waterproofing layer.
- Neglect the pool maintenance - Ignoring regular inspection, maintenance and repairs in the pool can cause minor cracks in the pool
- Allowing the debris in the pool - Allowing debris like leaves, sticks, and dirt to accumulate in the pool can cause clogs and damage the drain and waterproofing system.
- .
- Corrosion of the pool concrete reinforcements - The pool reinforcement structure can be damaged due to pool water. This can reduce the structural strength and waterproofing layer of the pool.
- Structural instability of the pool base - Structural instability can cause pool cracks and damage. These cause damage to the waterproofing layer of the pool.
- pH imbalance in the pool water - pH imbalance can increase the decaying and deterioration of the pool waterproofing membrane
- Using Harsh chemicals for abandoned pool cleaning - Overuse or misuse of chemicals in abandoned pools can damage the pool's waterproofing layer.
- Erosion around the pool can reduce the structural stability that causes waterproofing layer damage.
Do New Pools Require Immediate Waterproofing Like Old Swimming Pools?
Yes, you should waterproof the new swimming pool before you use it. The new swimming pool consists of a fresh concrete surface. The fresh concrete surface can react with the acidic and chlorine water in the pool. It can decay and deteriorate the material, and the pool reinforcement layer can corrode easily. These impacts can increase the pool structure damage. Therefore you should waterproof a new swimming pool using this 5 step guide.
Is Professional Help Necessary for Waterproofing an Old Swimming Pool?
Professional help, and expert knowledge are essential for waterproofing an old swimming pool if you do it DIY. If you miss any re-waterproofing step, the applied membrane can be damaged due to lack of adhesion. Therefore you should know everything about swimming pool waterproofing before you start the project. Else you have to hire an expensive, expert service for old pool waterproofing. Aqviz has included waterproofing guides for both old and new pool waterproofing. That will help you to conduct the DIY successfully.