The short answer
A waterproofing membrane is a continuous layer that stops water from passing through a balcony slab. On concrete balconies in Florida, the usual choice is a liquid-applied membrane that bonds to the prepared slab and runs up the edges without seams, finished with a protective coating and a slip-resistant texture. A sealer protects the concrete; a membrane stops the water.
Signs a balcony needs waterproofing
- Stains, bubbling paint or drips on the ceiling below.
- Rust stains around railing posts or cracks in the concrete near them.
- Tiles that sound hollow or come loose.
- Water that stays on the balcony instead of draining.
- Efflorescence, a white powder, on the edges or the underside of the slab.
The main types of membrane
- Liquid-applied membranes, rolled or sprayed on in layers. They form a seamless surface, follow the shape of the balcony and can take a traffic coating on top. They are the usual choice for balconies, terraces and walkways.
- Sheet membranes, rolls glued or torched onto the slab. They are common under tile or on roofs, and the seams are the weak point.
- Traffic coating systems, a membrane plus a wear layer made for foot or vehicle traffic, used on balconies, walkways and parking decks.
We choose the system for the surface, the water exposure and the traffic, working with professional-grade products such as Tremco and Vulkem, among others.
How a system goes on
- Inspection to find where water gets in.
- Mechanical preparation of the slab.
- Removal of damaged coatings that are no longer bonded.
- Repair of cracks, joints and holes.
- Primer where the system calls for it.
- The waterproofing membrane.
- A protective coating and finish, with a slip-resistant texture where people walk.
Details matter as much as the membrane: the edges, the joint with the wall, the drains and the railing posts are where water usually gets in.
Can it go over tile?
Sometimes. If the tile is well bonded and the problem is at the joints, some systems can go over it after preparation. If the tile is loose or water is already under it, it usually has to come off. We decide on site.
What it costs
It depends on the size of the balcony, its condition, the repairs and the system, so every job starts with an evaluation and a written estimate. See how much balcony waterproofing costs for what moves the price.
Next step
Send us photos of the balcony and of any stains below. See our waterproofing page for the surfaces we treat.
