DRYLOK review

The best-known name in basement waterproofing paint, and the one most often blamed for peeling. Both facts have the same explanation.

Buy DRYLOK Extreme, not Original, and apply it at the specified thickness onto bare masonry. Extreme is tested to 15 PSI of hydrostatic resistance under ASTM D-7088 and carries a 15-year transferable warranty; Original is not rated for standing pressure. Almost every account of DRYLOK peeling traces to one of three things: the wrong product, a coat too thin, or a surface that was painted before.

DRYLOK is made by UGL and is the most recognised name in negative-side basement waterproofing, which means it collects both the credit and the blame for a whole category. This review sticks to what the manufacturer publishes, and is clear about where a coating is the wrong tool entirely.

The DRYLOK range, in one table

Quick picks

#	Product	Best for	Score	Price
1	DRYLOK Extreme Masonry Waterproofer15 PSI of tested hydrostatic resistance and a 15-year transferable warranty — the only DRYLOK worth using on a wall that actually gets wet.	The one to buy	8.9★★★★	Check price on Amazon → #ad we earn a commission · Amazon shows the current price
2	DRYLOK Original Masonry WaterprooferThe lower-spec sibling. Fine on a wall that is damp and musty, wrong on a wall that weeps.	Damp walls without pressure	7.1★★★★	Check price on Amazon → #ad we earn a commission · Amazon shows the current price
3	DRYLOK Fast Plug hydraulic cementHydraulic cement that sets in three to five minutes and cures under running water — the step most people skip.	Stopping the leak before you paint	8.6★★★★	Check price on Amazon → #ad we earn a commission · Amazon shows the current price
4	DRYLOK concrete floor paintA latex floor paint for concrete. A different product with a different job, and often bought by mistake.	The slab, not the walls	7.4★★★★	Check price on Amazon → #ad we earn a commission · Amazon shows the current price

Scores are ours and editorial, not lab measurements — see how we pick. Tap a row for the full write-up.

What a 15 PSI rating does and does not promise

ASTM D-7088 pushes water against a coated masonry panel at a measured pressure and looks for passage through the film. A 15 PSI result means the dry film itself resists that pressure. What it does not mean is that your wall will stay dry at 15 PSI, because a wall is not a test panel: it has a cove joint at the floor, tie-rod holes, mortar lines of varying quality and sometimes a crack. Water finds the weakest route, and the coating only controls the routes it covers.

This is why a coating is the last step of a sequence rather than the whole job. Water arriving at the foundation is a grading and gutter problem; water already inside the masonry is a drainage problem; water at the wall face is the part a coating addresses.

#1The one to buy

DRYLOK Extreme Masonry Waterproofer

15 PSI of tested hydrostatic resistance and a 15-year transferable warranty — the only DRYLOK worth using on a wall that actually gets wet.

8.9/10★★★★★Our editorial score: 8.9 out of 10

Check price on Amazon →

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Specifications, as published by DRYLOK (UGL)

Type	Latex masonry waterproofer for interior and exterior masonry
Hydrostatic resistance	15 PSI, tested to ASTM D-7088
Coverage	75 sq ft/gal first coat, 75 to 100 sq ft/gal second coat
Film build	13 to 21 mils wet per coat; 17 mils dry minimum over two coats
Mildew	Biocide in the film to resist mildew growth on the dry paint
Shelf life	5 years unopened
Warranty	15 years, fully transferable, per UGL

The number that matters on this product is 15 PSI, tested to ASTM D-7088. That is a standardised hydrostatic pressure test, and 15 PSI corresponds to a substantial head of water pushing against the wall. It is the reason Extreme and Original are different products rather than different prices.

The second number that matters is the film build: 13 to 21 mils wet per coat, and a 17 mil dry minimum over two coats. Most people who report DRYLOK failing have applied it like paint — thin, rolled fast, one coat. At that thickness it is a white surface, not a waterproofing membrane, and water finds the pinholes.

Applied as specified, onto bare masonry, brushed into the pores on the first coat and recoated, it is a genuinely effective negative-side coating. The honest limitation is structural, not chemical: it holds water back at the wall surface, and it cannot hold back water arriving faster than the surface can resist. That is a drainage problem.

What it gets right

• 15 PSI hydrostatic resistance, tested to ASTM D-7088 — a published, repeatable figure
• 17 mils dry minimum over two coats, which is a real film rather than a colour change
• Biocide in the film resists mildew growth on the dry paint
• 15-year fully transferable warranty per UGL

Where it falls short

• Coverage is only 75 sq ft per gallon on the first coat, so you need far more paint than a normal wall paint suggests
• Must go onto bare, clean masonry — it will not bond through old paint

Specifications from DRYLOK Extreme product data sheet, DRYLOK Extreme product page.

#2Damp walls without pressure

DRYLOK Original Masonry Waterproofer

The lower-spec sibling. Fine on a wall that is damp and musty, wrong on a wall that weeps.

7.1/10★★★★★Our editorial score: 7.1 out of 10

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Specifications, as published by DRYLOK (UGL)

Type	Latex masonry waterproofer, the lower-spec sibling of Extreme
Use	Damp walls without standing hydrostatic pressure

Original exists for the wall that smells like a basement rather than the wall that leaks like one. If the masonry is cool and slightly damp but water never appears, Original will brighten it, reduce the vapour coming through and cost less.

The mistake we see constantly is buying Original to save money on a wall that needs Extreme, then concluding that DRYLOK does not work. The product was asked to do a job it is not rated for.

What it gets right

• Cheaper per gallon than Extreme
• Easier to work with, and adequate on a dry-but-musty wall
• Same preparation rules, so the skills transfer

Where it falls short

• Not rated for standing hydrostatic pressure the way Extreme is
• Being the cheaper option tempts people to use it where Extreme is required

Specifications from DRYLOK product range.

#3Stopping the leak before you paint

DRYLOK Fast Plug hydraulic cement

Hydraulic cement that sets in three to five minutes and cures under running water — the step most people skip.

8.6/10★★★★★Our editorial score: 8.6 out of 10

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Specifications, as published by DRYLOK (UGL)

Type	Quick-setting hydraulic cement
Set time	3 to 5 minutes
Works under water	Patches holes where water is actively flowing through them
Composition	Sand and cement, 100% solids
Coverage	16 cu in per lb

No coating bridges an active leak. If water is coming through a tie-rod hole, a pipe penetration or a gap at the cove joint, that gets plugged with hydraulic cement first and painted second. Fast Plug sets in three to five minutes and will cure with water running over it, which is exactly the condition that defeats ordinary mortar.

Mix no more than you can place in two minutes. Everyone's first batch goes off in the bucket; plan for it.

What it gets right

• Sets in 3 to 5 minutes and works on a hole with water actively flowing through it
• 100% solids, sand and cement — nothing to shrink back
• 16 cu in of coverage per pound, so a small tub goes a long way

Where it falls short

• Three to five minutes is a genuinely short working time; mix in very small batches
• Not a structural repair for a moving crack

Specifications from DRYLOK Fast Plug product data.

#4The slab, not the walls

DRYLOK concrete floor paint

A latex floor paint for concrete. A different product with a different job, and often bought by mistake.

7.4/10★★★★★Our editorial score: 7.4 out of 10

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Specifications, as published by DRYLOK (UGL)

Type	Latex floor paint for interior and exterior concrete
Use	Basement and garage slabs, after the slab is dry and etched

This is on the page because the names get confused in the aisle. Masonry waterproofer is for walls and is not rated for traffic; floor paint is for slabs and is not rated for hydrostatic pressure. Using either in the other's place is the single most common DRYLOK failure we hear about.

If the slab is the project, the preparation matters more than the paint. See how to paint a basement floor for the moisture test to run first.

What it gets right

• Made for foot traffic, which masonry waterproofer is not
• Straightforward to roll once the slab is etched
• Transforms how a basement reads without touching the walls

Where it falls short

• It is floor paint, not a waterproofer — it will not hold back hydrostatic pressure through a slab
• Needs a genuinely dry, etched slab or it lifts

Specifications from DRYLOK product range.

The four ways DRYLOK gets blamed unfairly

1. Applied over old paint. The bond is only as good as whatever is underneath. On a previously painted wall the coating holds, the old paint lets go, and both come off together.
2. Applied too thin. One rolled coat is nowhere near the 17 mils dry the data sheet specifies. The first coat should be brushed, worked into the pores, and followed by a second.
3. Applied to the wrong problem. A wall with a running crack needs hydraulic cement and possibly crack injection first. Paint over a leak and the leak wins.
4. Expected to fix a drainage failure. If the perimeter drain is blocked or absent, hydrostatic pressure will keep rising until it finds a way through. See interior versus exterior waterproofing.

How much you actually need

At 75 sq ft per gallon on the first coat, a basement with 600 square feet of wall needs roughly eight gallons for the first coat and six to eight for the second. That is the detail that surprises people at the register, and it is why buying by the five-gallon pail is normal for this product rather than extravagant.

If you would rather buy something else

DRYLOK is not the only documented option in this aisle. Zinsser WaterTite LX publishes 20 PSI of hydrostatic resistance against the same ASTM D-7088 test, KILZ Basement & Masonry Waterproofer is the cheaper like-for-like swap, and RadonSeal is a penetrating sealer with no film to peel at all. The three are compared against the DRYLOK figures above, coat for coat and PSI for PSI, in DRYLOK alternatives.