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Ask any pool specialist which layer matters most and the answer is usually waterproofing. Tiles give the look and equipment keeps water clean, but waterproofing keeps water in the pool and protects concrete, steel and soil. It is also where most mistakes happen, because it disappears under tiles within hours and its weakness shows only later. This article focuses on mistakes in choosing and applying waterproofing during renovation, why they happen and the right questions to ask before approving any system.
Why waterproofing is the backbone of renovation
Everything you spend on tiles, finishes and lighting depends on the membrane beneath working. If it fails, water reaches render and concrete, tile adhesion weakens, salts appear and steel may rust. In the end all finishes must come off to reach and fix it. Waterproofing is therefore not a minor technical choice to leave to a worker. You do not need to become a materials expert, but you need to know what to ask and which answers reassure you.
Using products not designed for pools
Each waterproofing product is designed for a use. Roof membranes handle sun and rain from above, bathroom products handle intermittent damp and tanks have their own needs. A pool membrane is permanently submerged, under water pressure and sanitising chemicals, beneath adhesive and tiles.
- Roof products may not tolerate constant immersion or bond well with tile adhesive.
- Some products resist damp but not continuous water pressure.
- Some systems need a protective layer before tiling and suffer without it.
Always ask whether the product is rated for permanent immersion and compatible with the adhesive and tiles above it.
Ignoring chlorine and salt resistance
Pool water is continuously chlorinated, and some pools use salt chlorination. Over time this chemistry affects materials, especially if water balance slips. The membrane usually sits under tiles, but water reaches it through grout and fine joints, so chlorine resistance matters even when covered. Keeping water balanced, including pH around 7.2 to 7.6, protects both membrane and grout.
Not accounting for Riyadh heat
In Riyadh, pools face high heat, dry air and day to night swings in some seasons, so the concrete moves slightly all the time. Waterproofing must accommodate that without cracking. Very rigid products may be strong but crack under repeated movement, so flexible or semi-flexible systems with extra reinforcement at corners and the waterline are usually preferred. Heat also affects application. Applying onto a hot surface in midday sun dries the product before it bonds, and can cause bubbles or fine cracks. Apply in cooler hours, dampen the surface if the product requires it and shade it while curing.
A single coat or insufficient thickness
To save time or material, waterproofing may be applied in one coat or thinner than the manufacturer specifies. A single coat may contain fine pores or weaker spots that a second coat covers, and adequate thickness gives the membrane its ability to handle movement.
- Ask how many coats and whether that matches the product instructions.
- Ask about time between coats, since recoating too early weakens both.
- Ask about reinforcing corners and fittings.
- Ask about testing the membrane before tiling where possible.
Neglecting surface preparation
The best product fails on an unprepared surface. It must be free of old adhesive, dust and oils, with cracks treated and weak areas removed. In renovation, failed old waterproofing must be removed, or the new product confirmed compatible if applied over it. New waterproofing on weak old layers is only as strong as the weakest layer beneath.
How to choose the right system
- Start with inspection of concrete and old waterproofing.
- Specify a pool system rated for immersion.
- Confirm flexibility for thermal movement.
- Confirm compatibility with adhesive and tiles.
- Have type and coats named in the quotation.
- Ask about timing and protection while curing.
- Request a written warranty on the waterproofing itself.
For more on available types, read pool waterproofing materials. YAM Pools starts with a free site visit, selects the system for your pool's condition, names it and its coats in a written quotation, and provides engineering supervision with a written warranty on workmanship and waterproofing. We serve Riyadh and all Saudi cities.
Frequently asked questions
What is the best pool waterproofing material?
No single product suits every case. The choice depends on concrete condition, finish and expected movement, but it must be rated for immersion, flexible and compatible with the adhesive.
Can new waterproofing go over the old?
Sometimes, if the old layer is sound and the products are compatible. If it is weak or debonded it must be removed first.
How many coats does a pool need?
It depends on the product and manufacturer instructions, usually more than one plus reinforcement at corners and fittings. Ask for the number in the quote.
Does a salt system affect waterproofing?
A salt environment calls for suitable choices of some materials and metal parts, so tell the contractor your sanitising system from the start.