Dry is better, and dry is what we recommend. Wipe the area down and give it time. On a surface that is merely cool rather than visibly wet it will still bond, but standing water or an active drip will stop it keying in properly. Deal with the water first, then coat.
50% OFF TODAY | HydroSeal™ - Stop the leak yourself, no contractor!
Brush it on and the leak stops. No contractor, no service call fee, no waiting on their schedule.
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Size
Color
Only 3 left in stock
50% OFF
Half price today. 20 fl oz does about 9 sq ft, 34 fl oz about 15 sq ft, at 2 to 3 coats. Measure your spot before you pick, and size up if it is close.
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30-day money-back guarantee
Join over 10,000 happy customers!
Specs and what is in the box
| Size | 20 fl oz or 34 fl oz |
|---|---|
| Net weight | 600 g (21 oz) or 1,000 g (35 oz) |
| Coverage | About 9 sq ft (20 fl oz) or 15 sq ft (34 fl oz), at 2 to 3 coats |
| Best for | A leak, a joint, a corner, a small patch. Not a whole roof |
| Colors | Clear, Gray, Black, Blue, White |
| Cured finish | Flexible waterproof rubber film |
| Surfaces | Concrete, tile, grout, wood, brick, masonry, metal |
| Where | Indoors and outdoors |
| Applied with | Roller or brush, no primer, no mixing |
| Temperature | Holds through summer heat and winter frost |
In the box
- ✔1 sealed tub of HydroSeal in the size and color you pick
- ✔Printed application instructions
A roller or brush is not included, any standard one works.
1250
reviews
Water had been coming through one seam on the garage roof for two winters. I kept putting off calling a roofer because of what they charge just to come out. Two tubs, two coats, one Saturday afternoon on that strip, and it has been bone dry since through some very heavy rain.
Henry Z.
- ✔Stops an active leak the same afternoon
- ✔No contractor, no service call fee, no waiting
- ✔Open the tub and roll it on, no primer
- ✔Holds through summer heat and winter frost
As seen in
Forbes
POPULAR MECHANICS
THE SUN
Which?
BBC
Forbes
POPULAR MECHANICS
THE SUN
Which?
BBC
It went viral on Pinterest, so stock keeps running out
Every wet season the leak repair pins take off again and this sells out. We hold back a small batch at the discount. When it is gone, it is back to full price.
The drip is not the expensive part
It is what the water does behind the wall while you wait for someone to come out and look at it.
$350 to $1,500
A roofer, for one small leak
That is the going rate to have somebody come out and reseal a vent or a section of flashing. You still wait your turn.
$45 to $55
Per sq ft of ceiling
Once the stain spreads, the drywall gets cut out and replaced. A small patch of ceiling turns into a real bill.
$1,200 to $3,750
Mold remediation
Damp sitting in a wall cavity is what mold needs. By the time you smell it, it is a specialist job.
Every one of those started as a damp patch somebody kept meaning to deal with. HydroSeal is what you do before the bill shows up.
Rain stops getting in, today
Find the spot the water is actually getting through, coat it, and by the next storm there is nothing left for it to find.
💧
Leak stops
Seals the crack the water was getting through.
🧰
No pros
You do it yourself. No service call fee to pay.
🌡️
Any season
Stays flexible in frost instead of splitting.
🍃
Mold starves
No damp in the wall means nothing to feed it.
Keep the money you were about to hand a roofer
A roofer charges $350 to $1,500 just to come out and reseal one small leak. A tub is $34.99, and nobody has to fit you into their schedule.
Open the tub, roll it on, that is the whole job
No primer, no mixing, no special tools. Same motion as painting a wall, and you are finished in an afternoon.
The damp corner that keeps coming back, gone
Seal the joint where water gets in and the black spotting has nothing left to grow on. Low odor, so it is fine indoors.
What customers tell us afterward
97%
Say the leak stopped after the first application
95%
Say it went on easily with no special tools
93%
Say they would handle the next leak themselves too
You will be done before the afternoon is over
No primer, no mixing, no special tools. If you can paint a wall, you can do this.
1
Wipe the spot dry
Brush off loose grit and let the surface dry. That is the whole prep.
2
Open it and roll it on
Straight from the tub with a roller or brush. Work it into the crack, then a second coat.
3
Let it turn to rubber
It cures into one flexible sheet. Rain hits it and runs straight off.
Photos customers sent in
Real jobs, done by people who had never used a sealer before.
"One seam on the garage roof was letting water into the ceiling below. Did that strip with two coats and it has stayed dry all spring."
Dale W. Verified buyer
"The grout in the shower kept going black. Sealed it in an hour, no smell, and it has stayed clean."
Renee A. Verified buyer
"Water was getting through where my balcony floor meets the wall. Quote was $600. Two tubs and an afternoon instead."
Marcus T. Verified buyer
Doing it yourself vs hiring someone
Same leak. Two very different weeks.
| HydroSeal | Roofer | |
|---|---|---|
| Cost for one leak | $34.99 | $350 to $1,500 |
| How soon | The day it lands | Wait for an opening |
| Who is on your roof | Just you | Strangers, ladders |
| What gets done | The spot that leaks | Often the whole roof |
| Next leak | Another $34.99 | Another service call |
| Works indoors | Bath, balcony, basement | Usually roof only |
| Color choice | 5, clear included | Whatever they carry |
The complaints you will read about sealers, answered straight
Read the one and two star reviews on any leak sealer and the same four turn up. Here is what is actually behind each one, and what it means for how you use this.
"It peeled off in sheets after two weeks"
Almost always an aerosol. A spray lays down a skin a fraction of a millimeter thick, and a skin lifts. HydroSeal goes on as a thick paste and cures into one continuous rubber layer. Thickness is the entire point, which is why it comes in a tub and not a can.
"The coverage was nowhere near the claim"
The usual cause is a label quoting one thin coat, when waterproofing needs two or three. So here is the number that assumes you do it properly: 20 fl oz covers about 9 sq ft, and 34 fl oz about 15 sq ft, at 2 to 3 coats. That is a leak, a joint or a corner. It is not a whole roof, and we would rather say so than have you run out halfway.
"It dried cloudy and ruined the look"
A fair complaint about clear sealers on dark surfaces. It is also why this comes in five colors. Use clear on tile and light stone, and gray, black, blue or white where you would rather it disappear into the surface than sit on top of it.
"It cracked over the first winter"
Rigid fillers crack because concrete moves and they do not. The cured film here stays flexible, so it expands and contracts with the surface through summer heat and winter frost instead of splitting along the crack it was meant to cover.
Try it on the worst spot you have. 30 days.
Put it on the leak that has bothered you the longest. If the next rain still gets through, tell us and take your money back. You are risking a wet afternoon, not $35.
What real customers are saying
From 1,250 recent reviews
Tom R.
Verified Buyer
Used it on the tile floor in the bathroom where water was seeping through the grout. No more leaks through to the ceiling below. Super effective.
Ben C.
Honestly great. I applied it to my balcony floor, which was letting moisture leak down to the neighbor below every time it rained. Result: the water completely beads up on it now.
David S.
Verified
I bought a wooden birdhouse to put outside. After painting it, I needed to protect it from the weather, so I used this sealant to keep water out. We have had plenty of rain lately and the inside is still pretty dry. It has performed excellently.
Mike T.
No more mold marks in the corner of the bedroom! I applied this last month and the wall has finally stayed completely dry despite condensation. What a relief.
John O.
Verified
Used it on my laundry room floor where there were often small puddles of water. The surface became completely waterproof and super easy to maintain. I'm going to apply it to other floors in the house.
Nick V.
Verified
Bought it skeptical, but after sealing roof seams the drip that drove me nuts stopped entirely. Feels reliable and long-lasting.
Sam B.
Verified
Treated multiple exterior surfaces around the house; after storms nothing leaked, no mold, and surfaces still look great months later. Big relief and saves money on repairs.
James K.
Instantly keeps surfaces dry and protected, preventing damage and extending their lifespan in all weather conditions.
Luke H.
Verified
Used on my deck and it repelled rain immediately, surfaces stayed dry and saved me a costly repair.
Chris L.
Verified
Instantly keeps surfaces dry and protected, preventing damage and extending their lifespan in all weather conditions.
Paul N.
Worked on basement walls to stop damp smells. Now the space is usable and healthier for the family.
Ryan M.
Verified
Instantly keeps surfaces dry and protected, preventing damage and extending their lifespan in all weather conditions.
Mark P.
Fixed a leaky wall after the rainy season, now it stays bone dry and mold-free for months.
Adam J.
I used this on the balcony floor before the rainy season and it kept everything dry. No leaks into the apartment below, so relieved!
Steve G.
Verified
Treated the siding and it’s like a shield against rain and sun. Surfaces look newer and I expect fewer repairs.
Frank D.
Verified
Applied on an old shed; after a month of rain there’s zero dampness inside and the wood seems preserved and stronger.
Eric W.
I coated the garage roof before winter and it held up through heavy storms, no drips and no mold showing up afterward.
The questions people ask before they buy
Straight answers on prep, curing, safety and what happens if it does not work
Will it stick if the surface is still a little damp?
Will it stick if the surface is still a little damp?
How much area does one tub actually cover?
How much area does one tub actually cover?
Waterproofing needs 2 to 3 coats, not one, so these are the figures at that thickness: the 20 fl oz tub does about 9 sq ft and the 34 fl oz tub about 15 sq ft. Rough or porous concrete drinks more than smooth tile. Think of it as enough for a leak, a joint, a corner or a small patch. For anything roof sized you will want several tubs, so measure first.
How long before it can rain on it?
How long before it can rain on it?
Give it a few hours of dry weather to skin over and a full day to cure through. Check the forecast before you open the tub, the same way you would with exterior paint.
Can I paint over it once it is dry?
Can I paint over it once it is dry?
Yes, once it has fully cured. Most exterior masonry and roof paints will go straight over the top. Do a small test patch first, as you would with any coating.
Is it safe to use indoors, in a bathroom or a basement?
Is it safe to use indoors, in a bathroom or a basement?
Yes. It is low odor and not solvent based, so a bathroom, laundry room or basement is fine. Open a window while you work and let it air out, as with any coating.
Will it crack in winter or bake in summer?
Will it crack in winter or bake in summer?
The cured film stays flexible instead of setting rigid, so it moves with the surface through frost and heat rather than splitting along the crack it was meant to cover. That flexibility is the reason it keeps sealing.
What surfaces does it actually work on?
What surfaces does it actually work on?
Concrete, tile, grout, brick, masonry, wood and metal. Roofs, gutters, balconies, shower corners, basement walls, sheds, planters. It does not need a particular surface, it needs a clean dry one.
What if it does not stop my leak?
What if it does not stop my leak?
Then it is not the right product for your problem and you get your money back. 30 days, no argument. Email us and we will take care of it.
The stain will still be there next time it rains
One tub, one afternoon, and it stops being your problem. Half price while this batch lasts, and every order is covered by the 30 day money back guarantee.
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