We did an epoxy floor coating in our Mississauga attached garage and simultaneously did a basement concrete assessment for a future finishing project. The moisture testing saved us from a major mistake.
Garage epoxy project:
2-car garage, 440 sqft, poured concrete from 2004. Concrete was in good condition — minor surface crazing, no heaving, no significant cracks. We went with a contractor-installed polyaspartic system (faster cure than standard epoxy, harder surface, better UV resistance).
Process: Shot blast to open the surface profile (CSP 3-4 required for polyaspartic). Crack fill (3 hairline cracks, $0 extra). Broadcast colour chips (full flake system, medium chip size). Top coat polyaspartic sealer x2.
Cost: $3,200 (440 sqft, all materials and labour). They were done in one day — polyaspartic is drive-on ready in 24 hours vs 72 hours for standard epoxy.
Basement moisture assessment:
We want to finish the basement. Before getting quotes, we did the plastic sheet test on 6 spots around the slab. Two spots (near the sump pit and one corner) showed significant condensation at 72 hours — indicating vapour transmission above acceptable levels for organic floor materials.
We rented a slab moisture probe and tested RH at 40% depth: the two problem spots were at 82% and 79% RH. Polyurethane LVP requires max 75% — we are over limit at those spots.
What this means for our finish plan: We will need either a moisture mitigation system (penetrating silicate sealer or full epoxy vapour barrier coat on the slab before the sleeper floor system) or a sleeper floor system on rigid foam with no organic top layer in the high-moisture corners. We now have a realistic scope to price.
Spending $180 on moisture testing before choosing finishes is the best money we spent on this project.