WATstop interior waterproofing
Water coming through the basement wall?
Seal it from the inside. WATstop is a three-part epoxy-cement that rolls onto bare concrete and holds back 139.6 psi of water pressure. Two coats now, paint over it in two days.
The yard stays untouched
Why excavate when you can seal it from the inside?
On an existing house, the excavation runs $10,000 to $25,000, and plenty of foundations can't be reached that way at all due to driveways, decks or a neighbour's house being too close.
From the inside, the water is pushing the coating away from the wall rather than against it, so the job needs a product built for the task. WATstop holds about forty times the water pressure an 8-foot basement wall ever sees, and its specialized formulation is what secures the bond to your foundation.
Coverage calculator
How much do you need?
Based on 2.0 kg per m² in two coats for full waterproofing, or 1.0 kg per m² for a vapour barrier. Both go on in two coats.The vapour-barrier rate is only for walls that test dry, under 5% moisture; if you're not sure, use full waterproofing. Rough or very porous surfaces take a little more, so round up if you're between sizes. Joints take one metre of Safety Joint Roll per metre treated; each roll carries 10 m (about 33 ft).
A weekend-sized job
How it goes on
Strip it to bare concrete
Take off any paint, sealer, efflorescence and loose material until you're down to sound concrete or block. Fill cracks and voids with repair mortar before you coat. WATstop seals the surface, but it won't bridge a structural crack.
Mix in the bucket
Mix the cement part (C) into the water with a drill and paddle until it's a smooth paste, then add the resin (A), then the catalyst (B). Everything comes pre-dosed in the bucket, and you have about 2 hours to use each mix.
Roll on two coats
Work the first coat well into the surface with a short-hair roller or trowel, then put the second on within 24 hours. At the wall-to-floor joint and in the corners, press Safety Joint Roll into the fresh first coat and let the second coat cover it completely. Keep the room above 5°C and under 70% humidity while it goes on; if it's musty down there, run a dehumidifier.
Make it a wall again
Paint, plaster or tile go straight over WATstop 24 to 48 hours after the last coat, so plan the finish before you start: 48 hours is the limit.
Not sure what you're looking at?
Send us a photo of the wall. We'll tell you if WATstop is the fix, what prep comes first and how much to order. You'll hear back the same business day.
Two sizes, one product
Pick your bucket
WATstop 5 kg
$206.99
- Full waterproofing: about 27 sq ft
- Dry-wall vapour barrier: about 54 sq ft
- The right size for one problem wall
WATstop 10 kg
$319.99
- Full waterproofing: about 54 sq ft
- Dry-wall vapour barrier: about 107 sq ft
- The better value per square foot
Safety Joint Roll
$72.99
- Elastic non-woven polyester tape for the wall-to-floor joint and corners
- 10 m roll, 15 cm wide: about 33 linear ft
- Pressed into the first coat, covered by the second
Water actively running in? Call us first.
A damp or seeping wall is exactly what WATstop is made for. A crack that's moving, or water streaming in while it rains, earns a conversation first because sometimes WATstop is the whole fix and sometimes it's the last product that goes on. Five minutes on the phone saves you a return. 1-866-326-8321
If email suits you better, send a photo of the wall and we'll size it up from there.
Do your homework
