Waterproofing block frost wall

[biggziff]

My block guys are suggesting I seal the block frost wall for my new garage. It's about 9 courses to grade in a few spots and we have clay soil with poor drainage. They said to use the tar foundation/roof sealer stuff sold at Lowes, etc and to put on 2 coats. Any opinions on this product? I need to get it done this weekend so not a lot of time to order product, etc.

thanks

 

[jaysberman]

I had that done on my cellar walls and it really helps keep the walls dry.

 

[bigman68]

Waterproof or damp proof there is a big difference. Tar would be damp proof, waterproof would be a more specialized product available at concrete supply houses. If you just want damp proof cheep surf at Lowe’s would be fine.

 

[Firebrick43]

Are you tiling a perimeter drain? Water proofing is only part of the equation. The best water proofing will be compromised by constant hydraulic pressure. I would suggest a dimple board drain plane over an actual applied waterproofed.

 

[biggziff]

Waterproof or damp proof there is a big difference. Tar would be damp proof, waterproof would be a more specialized product available at concrete supply houses. If you just want damp proof cheep surf at Lowe’s would be fine.

I don't know which they're going for. I'll ask. Thanks.

Are you tiling a perimeter drain? Water proofing is only part of the equation. The best water proofing will be compromised by constant hydraulic pressure. I would suggest a dimple board drain plane over an actual applied waterproofed.

Yes, full perimeter drain with 4" pipe, 2" crushed stone back fill to grade, trench will be left open.

I'm not sure what they're trying to accomplish as there is no basement/crawlspace, but I'm sure there's a good reason for this.

thanks

 

[theoldwizard1]

IMHO, you can NEVER truly "waterproof" any below grade wall. The best you can do is "suggest" that the water go down to a drainage/weeping system which will carry the water away.

The approach I have seen the most is a multi-layer approach. "Tar", waterproof membrane, dimple board, gravel back fill.

 

[uncletater]

Where are you located?

 

[Rich+]

I did this with my poured crawlspace when I added a french drain around the perimeter. In the roofing isle Henry's actually makes a foundation specific coating. It is roofing tar, but I think it has no fiber fill and maybe is less viscous.

It took me an afternoon to brush it on. I only did one coat as heavy as possible, which I think is fine in cool weather (won't run as fast). There may be better solutions out there, but this is a fast easy cheap improvement.

It is messy. Wear gloves, nasty clothes or tyvek coveralls.

 

[biggziff]

Where are you located?

upstate NY

 

[biggziff]

IMHO, you can NEVER truly "waterproof" any below grade wall. The best you can do is "suggest" that the water go down to a drainage/weeping system which will carry the water away.

The approach I have seen the most is a multi-layer approach. "Tar", waterproof membrane, dimple board, gravel back fill.

Thanks.

I don't understand trying to seal a block wall that will be backfilled with gravel. Still trying to figure that part out!

 

[DieselNut88]

On a small shed I am building I am going to use Zinsser Watertite. It claims it will block 34 psi of water. I have all sand soil though.

 

[Dr Klaun]

You do this so the water won't penetrate the wall above the frost line and then freeze / thaw your mortar joints apart. The block will absorb moisture as well unless you specified a CMU with a waterproofing admixture (dry-block).

 

[joes169]

Thanks.

I don't understand trying to seal a block wall that will be backfilled with gravel. Still trying to figure that part out!

From looking at the picture, and the brief description, it sounds like the grade is higher than the garage floor in part of the garage, so the potential for leaks into the garage is a possibility.

As for damp-proofing below grade block for freeze damage resistance, I can't say I've really every seen any real damage in dozens Maybe hundreds?) of older foundations we've gotten into.

 

[Lunker]

I would seal it and put on the black dimple board running to a drain tile with gravel

 

[theoldwizard1]

Thanks.

I don't understand trying to seal a block wall that will be backfilled with gravel. Still trying to figure that part out!

It is a retaining wall ! The gravel will help the water find its way down to the drainage tile/pipe.

All the previous steps mentioned also help the water move to the drainage pipe.


You will NEVER permanently seal a block wall. If there is water pressure out there, over time, it will leak.

 

[eastbaysubaru]

We seal all retaining walls with MasterSeal HLM 500 (two coats) and then cover that with layers of Meridrain. It's worked exceptionally well.

-Brian

 

[On-Wheel]

Have the block layer parge it with mortar with a cove at bottom for water to run away from wall.Brush on theraseal before mortar dry.Let theraseal dry and tar it and put some insulation board on.That would keep a basement dry!

 

[cmeeks]

I have a small (700 gallon) concrete pond / plunge pool I simply waterproofed by painting with Drylok. It works really well!

 

[biggziff]

From looking at the picture, and the brief description, it sounds like the grade is higher than the garage floor in part of the garage, so the potential for leaks into the garage is a possibility.

As for damp-proofing below grade block for freeze damage resistance, I can't say I've really every seen any real damage in dozens Maybe hundreds?) of older foundations we've gotten into.

Yes, grade is higher than some areas of the new floor (for now) and runs towards the building. We're going to run the drain tile in a french drain (open) all the way to the ditch at our road. Our lot is on a hill and is situated such that a lot of the hill runs towards our property. I've been adding french drains to stop the water making it to the yard closest to the house as it will remain wet for much of the year. We've never had water in the basement, but the wet yard is a pain when mowing, etc. I mow about 2 acres right now.

 

[theoldwizard1]

We've never had water in the basement, but the wet yard is a pain when mowing, etc. I mow about 2 acres right now.

Been there, done that !

 

[RSr]

The fact is that even though you have good drainage, water still wicks through block and mortar pretty easily. After a hard or steady rain, the block wall on the inside of your garage may be damp. Applying a surface coating as your block guys are suggesting along with the drainage should keep your wall dry on the inside. If this were a basement that is completely underground and where you might finish it in the future, then the coating plus water drainage mat come into play to really make the wall system "water proof".

 

[biggziff]

The fact is that even though you have good drainage, water still wicks through block and mortar pretty easily. After a hard or steady rain, the block wall on the inside of your garage may be damp. Applying a surface coating as your block guys are suggesting along with the drainage should keep your wall dry on the inside. If this were a basement that is completely underground and where you might finish it in the future, then the coating plus water drainage mat come into play to really make the wall system "water proof".

I ended up using 3 coats of the recommended foundation coating (used 2X the amount they suggested) and put a plastic vapor barrier on top of that before we backfilled with #2 crushed and pipe. If that's not good enough I'll be surprised.

 

[rburke65]

I like the insulation board against the tarred wall.