DRYLOK Extreme Masonry Waterproofer Review (2026)
By Nate Sawyer, Editor · Updated July 2026
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- Interior basement walls
- Foundation and block walls
- Below grade masonry
- Stopping water seepage under pressure
The go-to interior film-forming waterproofer for basement and foundation walls, rated to hold back water at up to 15 psi with a 15-year warranty. Best for bare masonry block or poured walls where you need a true waterproof barrier, not just a repellent.
Pros
- Encapsulated polymers bridge pores and stop water under up to 15 psi of hydrostatic pressure
- Backed by a 15-year waterproofing warranty when applied at two full coats
- Water-based cleanup and can be tinted, unlike bare penetrating sealers
Cons
- Requires bare, unpainted, unsealed masonry, so old paint or prior sealer must be removed first
- Two thick coats at 75-100 sq ft per gallon means it covers far less area than penetrating sealers
- As a surface film it can blister or peel if applied over a previously coated or dirty wall
Specifications
| type | Film-forming masonry waterproofer (latex) |
|---|---|
| finish | White paint-like film (tintable) |
| coverage | 75-100 sq ft per gallon per coat |
| coats | 2 coats required for warranty |
| hydrostaticRating | Stops water up to 15 psi |
| warranty | 15 years when applied per directions |
| cleanup | Soap and water |
Frequently Asked Questions
- Can DRYLOK Extreme be applied over painted basement walls?
- No. It requires bare, unpainted, unsealed masonry, so old paint or a prior sealer has to be removed first. Applied over a coated or dirty wall it can blister and peel, which is the most common way this product fails.
- How much water pressure can DRYLOK Extreme hold back?
- It is rated to stop water up to 15 psi of hydrostatic pressure, using encapsulated polymers that bridge the pores in the masonry. That covers real seepage, not a structural water problem - if water is actively running in, the drainage outside needs fixing too.
- How many coats does the warranty require?
- Two full coats, and the 15-year warranty only applies when it is applied per directions. At 75-100 sq ft per gallon per coat that is a lot of product for a basement, so measure the wall area and double it before buying.
- Can you paint over or tint DRYLOK Extreme?
- It is tintable, unlike bare penetrating sealers, and dries to a white paint-like film. Cleanup is soap and water.