O/T water leaking through block wall

37chief · Jun 7, 2011

Not many basements here in Calif, so I thought I will go to where they have them. I know many of you have them. So here is the problem. Our church has a cement block wall in the back. The wall is about 5 ft tall, with dirt piled behind it. Before the dirt was added it was sealed with someting abouut 20 years ago. No one seams to know with what. Every time it rains it leaks. Now for the question. Is there something to paint on the inside of the wall, to seal it? or a thin coat of something plastured on. The wall has been painted with regular paint inside. There is a cement walk way on the outside, so it will be a big deal to remove it. That is why I thought maybe something on the inside.Stan

David G · Jun 7, 2011

I would expect the walk has sloped backward against the building, you should put a level on it and check. The primary defense against water in a building is to get it away from the foundation. I do not think you can seal it otherwise.

Mudjacking the walk might be an option if it is sloped.

Mark - IN. · Jun 7, 2011

Stan, I saw some stuff at Menards and Lowes that they used to coat cinder block walls with, then ran a hose and water to fill one, showing how it sealed and held water, while the untreated block leaked water. If a wall has good mortar, then perhaps so on the outside. But in Indiana, ours are typically coated with tar and then buried. Cinder blocks aren't used much anymore because they have a tendency to be prone to shifting ground, breaking up the mortar and causing leaks. My last house with a cinder block walled basement leaked as well when we first bought it, so hand dug up the walls/foundation down to the cement the blocks were setting on, cleaned it all and tarred the living heck out of it, buried it again. That was the mid to late '70's, house was built in '57. Fortunately every house since was poured walls, so far less to deal with.

Good luck, but I think you and the church guys are going to have to grab the shovels and... Be careful of digging into old gas lines, power, etc.

Mark

funky_g00 · Jun 7, 2011

There are products that you can paint on the inside to stop water, any hardware store should carry a few different kinds in their paint dept. Personally I do not think they work as good as the sealers that go on the exterior. Regardless of what you use they are only water repellants and not water proof. TOO MUCH WATER IS TOO MUCH WATER, if it is a lot of water that you are fighting look at adding to or changing the drainage system.

M-MAN · Jun 7, 2011

You could seal the inside with that waterproofing paint from Lowes but if you want to save the foundation you need to do some digging. The way it's done around here is to spread a smoothe mortar coat on the outside of the block's. Then brush on a heavy coat of foundation coating. Then heavy plastic sheeting from ground level to the foundation. Then lay in a drainage line with a couple feet of gravel on top. Cover it up and forget it. Course the ground slope has to be away from the building.

noncompos · Jun 7, 2011

David G has a good point...there"s lots of stuff you can paint, slather etc on the inside, but if you seal the wall, where"s the water going??...further down to undermine the whole foundation on that side?? And if the blocks are just sealed on the inside, they"re continually soaking on the outside.
Watch it when it rains, find out where the waters coming from (leaking gutters, sloping towards wall, running in from parking lot etc), and keep it away from the wall (while you still have one). Good luck.

bison · Jun 7, 2011

Por-15 is supposed to work on that.Google it.
Pricy though

MarkB_MI · Jun 8, 2011

Like everyone else says, you can put waterproof paint on the interior, but unless you can divert the water away from the wall it's going to find a way in. Figure out where the water is coming from and try to divert it around the building. If it's runoff from the roof, gutters need to be added to the building. If it's coming from uphill, then a drain tile should be laid around the building. Once steps have been taken to divert the water, waterproof paint is still a good idea.

VADAVE · Jun 8, 2011

First time I ran into Block basement walls was when I moved to Virginia in the Seattle area basements have poured walls. I have owned 4 homes in Virginia all with block basement walls and all of them leak to some extent. One ran a strweam across the floor 1/4" deep when it rained. A leaking block wall will loose it's strength over time so the answer is to stop the leaking. If the wall is just getting damp and not running water there is a product called "DRI_LOCK" that will seal the wall.
If it is more then getting damp you will have to dig to the footers on the outside, close any broken blocks and point any motor joints. Paint it with a water seal AND put in a drain line.
If you don't want to do that then break up the floor inside and put in a curtain drain around the wall and dump it in a sump with pump then sell the place.

Big Irish · Jun 8, 2011

DryLoc paint, works well. About $20.00 a gallon made to stop water on interior walls. Doesn't go real far though, I think coverage is like 16 sq ft. Good Luck

Geo-TH,In · Jun 8, 2011

I would bet the church paved the parking lot and water is running toward the church. Dry lock will only work on new unpainted block.

I own a house built in 1920. Had to angle the dirt to make th water run away from the house.

omahagreg · Jun 8, 2011

As has been stated, if you seal it from the inside, the block will retain the water INSIDE itself. That is not good. You either need to seal it from the outside, or at least make sure it is running away from the building.

buickanddeere · Jun 8, 2011

Listen to MarkB_MI and those with similar advice.
You can't make the wall waterproof with "wonder glop" from the inside.
You can keep the wall from leaking if water is kept away from the outside.
Divert surface run off. Tile drain the wall from the outside from the base of the footings.back fill with drainage stone.
Never heard tell of a house around here without a basement. Unless it's a trailer.
Where do you store stuff, have a dirt room, laundry and utilities without a basement?

OldFarmTractor · Jun 8, 2011

Wait, you have your laundry in the basement?

I found that having the laundry near the bedrooms is GREAT!. That is where the dirty linens and clothes come from anyway.

And since drains flow downhill, it makes sense to have the laundry up higher.

Tony in Mass. · Jun 8, 2011

Almost all these guys, especially the northern guys, are steering you right. If this was Canadian dirt, I would say, yeah, soaked ground- deep. But what I know of california dirt, it is 99% run off, do that first, divert the flow, even if you don't see it flow, away- however, off to the sides and downhill. You guys could dig a ditch and lay some 4" perferated pvc pipe, keeping a grade downhill and away. Did they put in storm drains when they built the church? If so, tap into them, if not, yep, into the parking lot. After you do this, and water is still seeping in.... I'm sure some of your able bodied parisheners have picks and shovels, the inside paint is a more of a mold preventer, not really a flow stopper, and it means the holes in the cinder blocks are full.... where in Cal are you?good luck!

MarkB_MI · Jun 8, 2011

No basements in the Carolinas. Kind of difficult to keep stuff dry when you're storing it below sea level.

No basements in California, either. I assume it's because of those pesky earthquakes and mudslides.

paul · Jun 8, 2011

1. get the water sloped away from the building.

2. dig a shallow trench around the bottom of the inside of the basement wall, run short tubes from each block hollow to a tube in the bottom of the trench, seal it all back up. Yup, a lot of work going through the basement floor, but in some cases far less work than exposing the outside, and it gets the water out of the wall.

3. sealers on the inside can work for a while, but often keep the water in the block, and this eats up the concrete over time, as well as the pressure of the water tends to make it thorugh anyhow. Sealing the outside works; sealing the inside is a poor attempt.

--->Paul

buickanddeere · Jun 8, 2011

All gravity flow from my basement.

dhermesc · Jun 8, 2011

You've had better luck than I have. I have a 3' long patch that leaks about 6" below grade - drylock won't stop it from leaking for anything.

tjdub · Jun 9, 2011

As most replies here say: drainage, drainage, drainage. Ripping up the concrete outside and fixing the grade is probably the best solution.

Nothing you can put on the inside will seal it, BUT you can add drainage on the inside by breaking up the floor next to the wall and putting in an <a href="http://www.basementsystems.com/basement-waterproofing/basement-waterproofing-products/drainage-systems/waterguard.html">interior drainage system</a>.

Another option is to drill a bunch of holes into the soil on the outside of the wall and inject drilling mud (bentonite) into the holes. This jams up the leaks, but it's not permanent and doesn't stop the water completely. Maybe this is what was done in the past that nobody can remember what it's called? There are not many people doing it anymore.

O/T water leaking through block wall

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