Waterproofing a terrace and waterproofing a pool have less in common than it seems. On a terrace the water falls and drains away. In a pool shell the water pushes permanently against every joint, and on top of that it does so loaded with chlorine —or with salt, if you have salt chlorination— and with a pH that swings all year round.
That is why the pool system is a closed one: specific materials, in a specific order. It is not commercial rigidity, it is that any link you substitute is where the water ends up getting in.
The membrane: 1.25 mm, no less
For pools you use ECODRY120 or DRY120, 1.25 mm thick. They are the membranes of Revestech's SUBWATER system and they are formulated to withstand low pH, chlorine and salt chlorination.
They also have anticracking capacity: they bridge substrate cracks of up to 3.6 mm. In a concrete shell that settles, that is not an extra, it is what stops a microcrack from turning into a drop in the water level.
The 0.5 and 0.8 mm membranes are not suitable for pools. They are excellent for showers and terraces, but they are not designed to work submerged.
The substrate, before anything else
- Clean, stable and with no formwork release agent residue.
- Minimum compressive strength of 25 MPa.
- Residual moisture of 5 % maximum, measured with a hygrometer. Not by eye.
- Edges and junctions sorted out: the membrane will not save a badly formed angle.
The order of work
This is the part that most often goes wrong. The joints between sheets are butt joints, that is, edge to edge, with no overlap. And they are sealed like this:
- PRIMERPOOL over the joint area. It is a polyurethane primer and it is mandatory: without it the adhesive does not grip as it should under water.
- SEALPLUS over the primer.
- 13 cm joining strip (ECODRY BANDA or DRY BANDA) bonded over the joint.
- Second seal with SEALPLUS over the strip. This is what is known as double sealing, and in a pool it is not optional.
On top of this comes TECHPOOL, a polyurethane adhesive that Revestech marks as mandatory in the waterproofing of pool shells.
What nobody tells you until it is too late
Revestech makes the warranty conditional on using the system's products. If you swap the primer or the adhesive for another one from the hardware shop because it was to hand, you are left without backing in exactly the application where you are going to need it most.
The saving from swapping a tub of PRIMERPOOL for something else is a few euros. The cost of emptying a clad pool to hunt for a leak is of another order.
After waterproofing
Once the adhesive and the sealing have cured, the water-tightness test is carried out before tiling. You fill it, mark the level and wait. It is tedious and it is exactly the step that saves you the grief.
Once it is passed, your finish goes on top: glass mosaic, porcelain tile or whichever covering you have chosen, bonded with tile adhesive.
The system works the same on new shells and in renovation, and in many renovations you can work over the old covering without hacking it all off.
How it looks on site
An honest piece of advice
Of everything we sell, the pool is the least forgiving application. It is perfectly doable —you do not need an applicator certificate— but it is worth being clear about the material breakdown before ordering, not after.
Tell us the dimensions of the shell and we will tell you exactly what you need and in what quantity, with no obligation.
