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Thompson’s WaterSeal is the best-known name in clear waterproofers, and its current lineup includes the Waterproofer Plus Clear Multi-Surface Waterproofer (concrete, brick, masonry and wood) and the Clear Masonry Protector Waterproofer (masonry only). Both are easy, cheap-per-gallon products for homeowners who want water to bead on a patio, walkway or brick wall. The trade-off is that they are light-duty, need regular recoating and don’t publish much technical data.
| Type | Clear penetrating waterproofer (exterior only) |
| Chemistry | Not disclosed on product pages; applies milky white, dries clear, soap-and-water cleanup |
| Finish | Clear, natural look |
| Coverage | 50–375 sq. ft. per gallon, depending on porosity |
| Coats | Usually one light coat |
| Dry/recoat | Dry in 24–72 hours; recoat after 72 hours (Multi-Surface: 72 hours to 45 days) |
| Cure | Keep above 50°F for 48 hours after application |
| Application temp | Air and surface above 50°F; no rain for 24 hours |
| Best for | Patios, walkways, pavers, brick, stone and stucco |
| Not for | Below-grade walls with water pressure, painted or recently stained surfaces |
| New concrete | Wait at least 4 weeks |
| Sizes | Multi-Surface: quart to 6 gallon; Masonry Protector: 1, 1.2 and 5 gallon |
Watch: Thompson's WaterSeal in 60 seconds
What It Is / How It Works
Thompson's WaterSeal sells several clear waterproofers for wood and masonry. For concrete and masonry, the two relevant products today are:
- Clear Multi-Surface Waterproofer for concrete, brick, masonry and exterior wood.
- Clear Masonry Protector Waterproofer for pavers, brick, concrete, stone, stucco, and clay and quarry tile.
Both soak into the surface and leave a clear, water-beading finish. They go on milky white and dry clear, and wet tools clean up with soap and water. Thompson's doesn't list the active ingredients or solids content on its product pages, so it's hard to compare their strength directly with silane/siloxane sealers that publish those numbers. Thompson's says both products resist mildew and UV damage and help maintain the surface's natural color.
Where It Works Best (and where it doesn't)
These are good matches for a homeowner treating a patio, front walk, paver area or brick planter who wants an easy, one-coat job from a pump sprayer. The Multi-Surface version is handy if you're also doing a wood fence or deck rail in the same weekend.
Thompson's is clear about the limits: don't use them below grade where water pressure is an issue, and don't apply over painted or recently stained surfaces. They're exterior-only. Lifespan also "varies by environment," and Thompson's asks you to splash test once a year to see if you need to reapply. Surfaces that face the sun and heavy foot traffic usually need it sooner. For driveways that see deicing salt and hot tires, a dedicated product from our best driveway sealers list is a better long-term buy.
Pros
- Widely sold and easy to find in hardware and home stores
- Simple one-coat application with a garden pump sprayer, brush or roller
- Dries clear and keeps the natural look of concrete and masonry
- Soap-and-water cleanup for wet product
- Multi-Surface version handles wood and masonry with one can
- Built-in splash test makes it easy to know when to reapply
Cons
- No published chemistry, solids or service-life data
- Needs regular recoating; Thompson's recommends a yearly splash test
- Long dry time (24–72 hours) and a firm 50°F minimum for 48 hours after
- Can darken or turn tacky if nights drop below 50°F too soon
- Not for below-grade water pressure, painted or stained surfaces
- Smooth concrete must be etched first for the Multi-Surface product
How to Apply It
- Do the splash test. Sprinkle water on the surface. If it soaks in and darkens within about five seconds, it's ready for treatment. If it beads, it doesn't need protection yet.
- Make sure new concrete or stucco has cured at least 4 weeks and is dry. Thompson's calls for etching smooth concrete before using the Multi-Surface product.
- Clean the surface and let it dry. After cleaning or rain, wait at least 72 hours for concrete, brick and masonry (48 hours for wood).
- Pick your weather. Air and surface must be above 50°F during application and for 48 hours after, with no rain in the forecast for 24 hours.
- Stir well and don't thin it or mix it with other waterproofers. Cover plants and test a small patch first.
- Apply one light, even coat with a pump sprayer, brush or roller. Spread or wipe up any puddles within 15 minutes.
- Let it dry 24–72 hours. Recoat no sooner than 72 hours, and only if the splash test says a spot still absorbs water.
How It Compares
Seal-Krete Multi-Surface All-Purpose Water Repellent is a similar big-box, water-based product. Its data sheet is more detailed: 150–300 sq. ft. per gallon, recoat in a few hours and foot traffic in 24 hours. That faster turnaround is handy if your weather window is short.
Dedicated silane/siloxane penetrating sealers publish their active content, coverage and expected service life, and many are rated for driveways and deicing salts. They cost more per gallon, but the better ones state how long they're designed to last, which makes it easier to plan recoats. Our best silane siloxane concrete sealers guide covers the stronger options.
Film-forming acrylic sealers add sheen or a wet look and resist stains better on patios, but they can peel and get slippery. If you want a natural look, a penetrating product like Thompson's is the safer choice.
FAQ
Does Thompson's WaterSeal work on concrete?
Yes. Both the Clear Multi-Surface Waterproofer and the Clear Masonry Protector are labeled for concrete. The Masonry Protector is the more focused choice if you're only treating concrete, pavers, brick or stone.
How long does Thompson's WaterSeal last on concrete?
Thompson's doesn't give a fixed number of years. It says lifespan varies by environment and recommends a splash test once a year. When water stops beading and soaks in, it's time to reapply.
Can you paint over Thompson's WaterSeal?
For the Clear Multi-Surface Waterproofer, Thompson's says to wait 45 days before using latex paint and at least 3 days before oil-based paint.
Will it stop a leaking basement?
No. Thompson's says not to use it below grade where water pressure is a problem. See our best waterproofing concrete sealers guide for products made for that job.
Verdict
Thompson's WaterSeal clear waterproofers are fine for light-duty patios, walks and brick where you want a natural look and an easy weekend job. They're easy to find and simple to use. Their long dry times, strict temperature rules, lack of published chemistry and need for frequent recoating keep them behind dedicated concrete sealers for driveways and high-exposure surfaces. Our rating: 3.2/5
How we reviewed this product: this is a research-based review built from the manufacturer's technical data sheet and current retail listings. We have not run our own hands-on tests of this product. Details were checked in October 2026; always follow the current label.
Where to Buy
Related Guides
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DRYLOK Original Concrete & Masonry Waterproofer is a thick, latex-based coating you brush or roll onto basement walls, foundations and other masonry to stop water seeping through. It’s one of the best-known DIY basement waterproofers, and it’s backed by a 10 psi hydrostatic pressure rating and a 10-year limited warranty. The bottom line: it works well on bare, properly prepared masonry walls, but it’s a wall paint, not a floor sealer, and it can’t fix cracks, drainage problems or water coming in at the floor joint on its own.
| Type | Film-forming masonry waterproofing coating |
| Chemistry | Latex base, about 66% solids by weight; rated below 1 perm |
| Finish | Flat, sandy texture; White or Gray, tintable to light shades |
| Coverage | First coat about 75 sq ft/gal; second coat 75–100 sq ft/gal |
| Coats | 2 minimum |
| Dry/recoat | Touch dry 1.5 hours; recoat in 2–3 hours |
| Cure | Can be topcoated with latex paint after 24 hours |
| Best for | Bare basement walls, foundations, block, brick, stucco, poured concrete walls |
| Not for | Floors or other horizontal surfaces with foot traffic; over existing paint |
| New concrete | Cure 28–30 days or until pH is below 10 |
Watch: DRYLOK Original in 60 seconds
What It Is / How It Works
DRYLOK Original is a heavy-bodied latex coating that fills the pores of masonry and forms a semi-impermeable film. It's still sold under the same name. DRYLOK was originally a United Gilsonite Laboratories (UGL) brand and is now part of Sika, which publishes the current data sheet.
The key numbers from Sika's data sheet: it's rated for 10 psi of hydrostatic pressure, which DRYLOK describes as the equivalent of a 22-foot wall of water (tested to ASTM D7088). It also resisted wind-driven rain at 98 mph and is rated below 1 perm for vapor transmission. That low vapor rating is part of why it works on basement walls, and DRYLOK says it also reduces radon penetration by limiting vapor transfer.
Unlike a clear penetrating sealer, DRYLOK Original changes the look of the wall. It goes on like thick, gritty paint and dries to a flat white or gray finish. You can tint it lightly or topcoat it with latex paint after 24 hours.
Where It Works Best (and where it doesn't)
It's made for vertical masonry, interior or exterior, above or below grade: poured concrete foundation walls, cinder and concrete block, brick and stucco. It's also used on fish ponds and non-potable tanks, per the data sheet. Typical uses are damp basement walls, block crawlspaces and foundation walls with seepage.
It isn't for floors. Sika's data sheet says plainly that it's "not formulated for horizontal surfaces subject to foot traffic" and points to DRYLOK Floor & Wall instead. It shouldn't go over existing paint, and doing so voids the warranty. It also won't seal active cracks, holes or the joint where the wall meets the floor; DRYLOK says to patch those first with a hydraulic cement such as its Fast Plug. If water is pouring in from outside because of grading or gutters, a coating won't solve that. For clear options on exterior slabs, see our best waterproofing concrete sealers.
Pros
- Rated for 10 psi hydrostatic pressure, high for a DIY coating
- 10-year limited warranty that transfers to later owners
- Water-based latex with soap-and-water cleanup
- Brightens basement walls and can be topcoated with latex paint
- Widely available and highly rated by buyers; owners commonly report drier basement walls after heavy rain
Cons
- Low coverage (75–100 sq ft per gallon per coat), so a basement takes a lot of product
- Must go on bare masonry; painted walls need stripping first
- Not for floors or other walked-on surfaces
- Thick, sandy-textured product that has to be brushed or back-brushed into the pores
- Warranty excludes recurring efflorescence and failures from poor prep
- Some owners report needing extra coats over patches or seeing it bleed through
How to Apply It
- Clean the wall. Remove dirt, dust, grease, oil, form release compound and paint. Take off any paint in poor condition. If you're scraping old paint, use a NIOSH-approved respirator and HEPA vacuum in case of lead.
- Patch first. Fill holes, cracks and the floor/wall joint with a hydraulic cement such as DRYLOK Fast Plug.
- Remove efflorescence with an etching solution or muriatic acid. Smooth surfaces need acid etching or mechanical abrasion to a medium-sandpaper texture. For damp walls, DRYLOK recommends its Wet Wall Bonding Primer.
- Check conditions. Air and wall must be 50°F or warmer. Apply to a dry surface during a rain-free period, and test a small area first.
- Stir well and don't thin. Keep stirring during use because the solids settle.
- Apply the first coat at about 75 sq ft per gallon with a DRYLOK brush, nylon brush or 3/4" nap roller. If rolling, back-brush to push it into the pores.
- Apply the second coat after 2–3 hours at 75–100 sq ft per gallon. If any spots still leak, recoat them. You can paint over it with latex after 24 hours.
How It Compares
DRYLOK Extreme is a separate latex masonry waterproofer in the same family, sold alongside Original at home centers. If you're choosing between them, compare the pressure rating, coverage and warranty on each current label rather than assuming they're interchangeable.
Clear silane/siloxane water repellents such as Rust-Oleum OKON S-40 or Rainguard Micro-Seal keep the wall's natural look and stay breathable. They're great on exterior brick and block that gets rained on, but OKON's own data sheet says S-40 doesn't protect against hydrostatic pressure, so they aren't a substitute for DRYLOK on a seeping basement wall.
Exterior excavation and membrane systems or interior drainage handle severe water problems that no coating can. If you have standing water or active leaks, talk to a basement waterproofing contractor first.
FAQ
Does DRYLOK really stop water?
On properly prepared bare masonry with two full coats, DRYLOK rates it to stop water up to 10 psi of hydrostatic pressure. It won't stop water coming through unpatched cracks, the floor/wall joint or from poor drainage outside.
Can I use DRYLOK Original on a basement floor?
No. The data sheet says it isn't formulated for horizontal surfaces with foot traffic. Use DRYLOK Floor & Wall or a floor-rated coating instead.
Can I put DRYLOK over painted walls?
DRYLOK's warranty requires a bare surface, and applying over existing coatings voids it. Remove the paint first so the product can bond with the masonry.
How long does DRYLOK last?
It carries a 10-year limited warranty when two coats go on a properly prepared, bare vertical masonry surface. The warranty covers product replacement or a refund, not labor.
Verdict
DRYLOK Original remains a solid, affordable choice for damp basement and foundation walls. Its 10 psi rating, 10-year warranty and long track record set it apart from clear sealers. Success depends on prep: bare masonry, patched cracks, removed efflorescence and two full coats. Keep it off floors, and fix outside drainage problems first. Full details are on the DRYLOK product page. Our rating: 4.2/5
How we reviewed this product: this is a research-based review built from the manufacturer's technical data sheet and current retail listings. We have not run our own hands-on tests of this product. Details were checked in October 2026; always follow the current label.
