Help me Fix this Basement Wall Water Damage

frogsterMarch 21, 2013

All,

Below is the picture of my basement wall after we removed the wall of mirror and paneling. We have consulted with a structural engineer about the crack and are going to use a carbon solution of some kind or going to run rebar and grout into the cinder block.

On the water damage on the far end of the wall, this is what the contractor proposes: "The exterior pavers and concrete base along the wall will be removed 4 to 5 feet back along the entire 42 foot foundation wall. The fill along the entire length of the foundation wall will be excavated 5 feet down. The existing block in the window well will be demoed and replaced in a proper fashion. The exterior of the wall will then be pressure washed and any minor fixes (minor parging) to the substrate will be done. The exterior of the wall will be waterproofed 5â down along the entire length, with a cold applied liquid membrane, Henry CM100 or equal. Once the membrane is cured, the area will be backfilled and compacted to grade. As an option, the interior wall will be waterproofed with Thoroseal."

We will also be working on regrading the outside so that the water flows away from the house.

Does what the contractor suggest make sense. Should we use the optional Thoroseal?

Thanks in advance for your input!

Frogster

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worthy

Since the biggest expense is the excavation and you don't want to do it again, I'd take every measure possible to be sure this is a one-time event. Check and replace, if necessary, the weeping tiles, use a cove sealant (where the blocks meet the footings) and add a layer of plastic bubble membrane, such as Delta MS. This will bridge any future cracks that the elastomeric can't bridge. As an alternative, the Henry CM100 can also be used in two coats with a Polyfab polyester fabric.

The backfill should be a free-flowing material--sand is best. I understand the contractor will be compacting because you want to put back pavers and you don't want them to tilt towards the house again. I would not compact the fill--as this will impair its ability to drain to the footings. Instead, use the free-flowing fill, loose lay the pavers. And when they tilt in a few years, lift them and put down more material.

Bubble membrane around the foundation provides backup protection against water leaks.

This post was edited by worthy on Thu, Mar 21, 13 at 18:39

    Bookmark   March 21, 2013 at 1:47PM
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frogster

Thanks! I should have been clear that they are not going all the way down to where the exterior wall meets the footing. The 5' down they are talking about is essentially from the top of the wall. (The window that used to be in the wall was below grade.) Because the water "appears" to have been coming in from the top of the wall, does it make sense to go through the extra expense of excavating all the way down. I understand that the last few feet of excavation is more expensive and could potentially put the wall at more risk by removing the stabilizing force of the wall. (The House was completed in 1969.)

If we choose not to excavate all the way down, should we then compact the fill so that water does not drain down to the point where we stopped excavating and then look to seep in?

Am I correct that if we do the Thoroseal inside as an option that we should wait some time after doing the outside and run dehumidifers to try and dry out the moisture from the blocks? Or, is that not really necessary.

Frogster

    Bookmark   March 21, 2013 at 3:47PM
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5' down they are talking about is essentially from the top of the wall.

It's a judgement call whether to excavate another 2.5-3 ft. deeper to be sure the entire wall is state of the art. I certainly wouldn't compact the new fill. If the weepers--assuming there are any--are working, you want the water to go down to them and drain away. I believe clay weepers were still in use in '69, in which case you can be all but sure they're not functional. And, to confuse matters more, if you have free-flowing material at that level, weepers may not be necessary at all! (Only so much one can suggest at this distance.)

The house isn't endangered by the excavating--unless it's being done by a careless machine operator. By hand is always best!

I've used Permaquik crystalline waterproofing in both exterior and interior applications. Sometimes as the primary waterproofing, other times as a secondary in addition to the bubble membrane.

*******

Did your structural engineer determine what caused the crack along that section of foundation? Water leaks leading to frost-push damage?

********
How bubble membrane works in conjunction with weeping tiles to keep the foundation wall dry

This post was edited by worthy on Thu, Mar 21, 13 at 20:06

    Bookmark   March 21, 2013 at 7:53PM
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frogster

Thanks again. I will find out if the structural engineer found or hypothesized about the cause of the problem.

Does it make sense to follow the approach you have outlined if there is no where to run the tube at the bottom to remove the water? That wall of the house is pretty close to blocked in by a pool on one side and a garage on the other side.

frogster

    Bookmark   March 21, 2013 at 9:37PM
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If there is a weeper beside the footing, it has to drain somewhere. Where I build, they're required to come back into a basement sump from which the water is then pumped out to the yard. Previously, we were able to hook the weepers into the municipal storm drains. In some areas, weepers are connected to underground drainage systems; or, if the house is on a hill, to a daylight drain.

Your proposed remedy may well work. All I'm pointing out is that it's far from ideal or complete.

    Bookmark   March 22, 2013 at 12:58AM
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frogster

Thanks very much. Your posts were very helpful in figuring out there was some confusion among the various parties about who was responsible for proposing solutions to which problems.

My big concern is if they get all the way down to the bottom of the wall and realize there is no good drain solution, what do they do then. But, we will face that problem if/when it arises.

    Bookmark   March 22, 2013 at 2:01PM
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My big concern is if they get all the way down to the bottom of the wall and realize there is no good drain solution, what do they do then

The conundrum is if there are old broken clay tiles at the bottom. So you put in new flexible plastic with a sleeve. But you're still left with connecting it to old clay on the rest of the house. At least, you can be sure the wall and the cove itself are waterproofed and hopefully not much water is coming down from the surface. Downspouts drained off far from the house. Proper grading. etc.

    Bookmark   March 22, 2013 at 4:26PM
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brickeyee

"Downspouts drained off far from the house. "

At least twice the depth of the basement below grade.

    Bookmark   March 24, 2013 at 11:32AM
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