Direct answer
Ceramic tile and grout are finish layers; they are not designed to hold hydrostatic pressure from a pool shell on their own. Leaks appearing months after tiling usually trace to the waterproofing plane beneath: disbonded coating at a cold joint, unsealed penetration, or cracks propagating from structure through a thin or missing membrane.
Petroseal’s swimming pool application and system pages describe primary waterproofing before tile, inspection holds, and compatible transitions at sumps and returns. Competitors (Unicorn, Water Seal, and others) may offer pool services—compare documented system build-up and product TDS, with Petroseal polyurea and coating lines where seamless shell lining is specified.
Common failure paths
- No primary waterproofing specified—tile direct on porous concrete
- Waterproofing applied on uncured or contaminated shell
- Penetrations (returns, lights, skimmers) without compatible collars
- Coating damaged by rebar or trades before tile
- Structural crack movement not addressed in design
- Incompatible tile adhesive solvent attacking the membrane
Correct sequence (new pool)
- Shell concrete to spec; cure; repair honeycomb
- Primary waterproofing per Petroseal pool system (polyurea or approved build-up)
- Holiday test or manufacturer QA hold
- Tile bedding compatible with waterproofing data sheet
- Grout and expansion at structural joints per detail
Retrofit reality
Existing tiled pools need leak mapping (dye test, pressure, selective tile removal) before any contractor applies surface sealant. Petroseal can advise on remediation scope when shell access is available; marketing-only chemical brush coats without diagnosis repeat failures.