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Landscape problem for church

Posted by hilltop z4 nebr (My Page) on
Thu, Sep 22, 11 at 10:19

I'm council chair of our church in a very small town in Nebraska so we have hot summers, cold winters and snow.
We're having basement wall water issues that we're trying to address. We removed the landscape rock and edging and found a mucky mess. The grass area was dry. We discussed planting grass, then someone mentioned concrete (but there's concern about having adequate expansion joints). Another person suggested installing drain tile, but I was standing on a sidewalk when I took the pictures so we'd have to remove that or bore underneath, plus there's a sprinkler system and multiple utility lines in our path. I'm coming here because we're divided on what to do. The gutters are big enough and clean. As you're looking at the first picture you're looking west. The area doesn't get much sun. The alcove or U-shaped area is 12' wide by 24' deep and then the open area is another 10x24'.

Prior to the new addition (with siding), there used to be an enclosed stairway back in the alcove where the two windows have been bricked up. We removed and enclosed it in
2002.

The interior basement wall indicates moisture issues, but only seldom has the basement carpet been wet. The basement floor is carpet on top of wood, then a dead air space about 4" deep and then a concrete base. The walls/floor are monolithic. The concrete base shows no sign of moisture.
I've been told that the exterior walls were tarred or treated within the last 6 years or so.

Here are a couple pics. Any suggestions on what to do on the exterior? No one ever sees the area since it's on the backside of the church.

IMG_1573

IMG_1571


Follow-Up Postings:

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RE: Landscape problem for church

I realize this isn't a design question, more of function. But I value this groups knowledge.
Also, we'd removed the downspouts when we took out the rock. The downspouts were both a good 12' long, extending beyond the edging.


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RE: Landscape problem for church

  • Posted by bahia SF Bay Area (My Page) on
    Thu, Sep 22, 11 at 11:58

It sounds like you have some water build-up against this wall even though you have leaders on the downspouts. That take the roof drainage another 12 feet away. Do you have a positive slope away from this back wall, or is it as flat as it appears? It also sounds like the exterior below grade walls were not built with a waterproofing membrane and adjoining french drain to keep out moisture and direct it away from the wall, which is the only guaranteed method to really keep moisture from penetrating inside the wall. Just curios, is the wall wood framed with a brick veneer at the below grade sections, or is it reinforced concrete, or something else? If there is wood framing above this below grade section and/or below grade, you probably also have dry rot and termite issues as well.


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RE: Landscape problem for church

Once any grading and building structure issues are addressed... (It looks like you have about 4-6" to raise this area before it would go above the concrete - in some spots.)

If this was covered by a rock mulch, that would have prevented water from evaporating there. If there were no thirsty plants to use that water, and it is heavy clay, you would get "mucky mess." Some ground cover and small shrubs with deeper-but-not-strong-enough-to-ruin-walls roots could do a lot in regard to using the moisture in this area. No more rock mulch there.


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RE: Landscape problem for church

There is some slope away from the back wall. We brought in a laser to measure. Just spoke to the architect at the time the basement door was taken out 8+ years ago. He doesn't remember how the door was enclosed and he doesn't think the contractor who did the work at the time is even still in business. He didn't have records that far back close at hand. All of the contractors I've spoken with said we took the right step in getting rid of the weed barrier, rock and edging. Most have said they think that concrete would be ok if we put rolled foam (or something like that) next to the building and had enough expansion joints. One said that if we couldn't get work done yet this fall since most contractors are already booked that we could let it dry out for awhile and then top it with gravel with a binder or yellow clay to kind of seal it off and keep any more moisture from penetrating through.


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RE: Landscape problem for church

From what I can see in the pictures it looks like you have pitch away from the building. Perhaps it could be slightly more "swaled" but I can't determine that from the photo. I think gravel mulch is incidental, not a cause to your problem with dampness in the basement.

You say, "I've been told that the [foundation] exterior walls were tarred or treated within the last 6 years or so." How reliable is this claim...and what does "treated" mean? The photos only show a possible hint of it, not conclusive evidence. This would have needed to be done during original construction or it would have been a major job later. So it's not as though it would skip anyone's notice. And as Bahia suggests, the "french" drain at the bottom outside of the wall is necessary to remove any water that collects in the percolation or any other process. This drain would have to have an outlet. Where is that? To my thinking, the waterproofing and drainage of the foundation exterior wall is the most likely avenue to explore...and the most likely place to solve this problem.


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RE: Landscape problem for church

The entire wall is poured concrete except where the basement door (36") used to be (under the second filled in window). I'm not sure how they enclosed the former door opening (and I haven't found anyone yet that knows), but if it was wood framed, they coated it with concrete because if we dig down a short ways, we see/feel concrete. The contractor at the time did a fantastic job on the new addition which makes me think he would have continued to do quality work when he enclosed the door and filled in that area. I hadn't even thought about termites--termites wouldn't have had direct access from the bottom because there was a concrete door lip there. Guess they could possibly get in through a small crack - but termites would only be a problem if it was a wood frame with untreated lumber. Structurally it's very sound, just the efflorescence on the interior wall that's causing concern.

I went back today to see what it looked like and it was amazing how much the soil had dried up in just two days.


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RE: Landscape problem for church

Sometimes you need to stand way back and take a really big picture approach with water. Example: my neighbour used to have a problem with water getting into her basement. If you looked just at her property, you would think that the perimeter drainage or foundation permeability was the issue. But if you stood way back you noticed that her property was the lowest on the block, so that all of us were probably contributing water to her lot. She planned her solution accordingly, and now the basement is dry.

Also, look up. Your downpipes may indeed be delivering water out 12 feet, but that is still within this area. How much roof area are they draining? Has this changed? Even if it has not, perhaps the creation of the addition has simply reduced how much water the soil can hold (well of course it has - there is less soil, I presume) or the pressure/flow through the soil. Or is the addition now also sending a downpipe into this area?

I was initially thinking you might be able to put a glass roof over this area or something, but you can probably keep a lot more water out of it by redirecting roof water by sloping the gutters differently and taking the downpipes somewhere else entirely.

Karin L


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RE: Landscape problem for church

  • Posted by bahia SF Bay Area (My Page) on
    Fri, Sep 23, 11 at 1:08

That entire wall below grade would need to have a moisture barrier coating along with a french drain continuously along the base of the wall and have an outlet away from the building to effectively keep out all aubgrade moisture. The contractor who filled in that doorway should be able to tell you both what the existing conditions were adjacent his work as well as what he installed to tie into it. You also don't seem to be aware that treated wood framing is no guarantee against termites, and constant moisture encourages termites. It sounds like the existing wall may not have been adequately detailed against water infiltration, or the newer work done at the closed up doorway was not done properly if your water problems only date since this work. If the soil is actually properly sloped at minimum 2% slope away from the building, adding concrete in the area may help, but only if there isn't a problem with subgrade water pressure at the wall.


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RE: Landscape problem for church

Bahia, I agree with all you say. What do you think is the easy way to discover conditions? I think if this were my situation, I'd manually dig down couple of feet depth with a shovel (in one place ...as an exploration) and inspect the exterior foundation wall for the waterproofing coating. It would appear like black paint. (If there is type of waterproof coating that appears otherwise, I am not familiar with it so others can advise.) If the coating exists, I would check/explore another place for further confirmation.

If the waterproofing does not appear to exist, then that's confirmation that further exploration is necessary. If it's surmised that waterproofing is not present, then the foundation needs to be exposed (dug up) and waterproofed. (If there's any other way, others can advise.)

It's possible to discover that waterproofing exists, but does not come all the way up to grade surface level. If a drain channel does not exist, it needs to be created. I'm thinking that in some cases the drain may not run to a lower elevation outlet somewhere in the landscape, but to a sump pump that is located within the building. It depends on Nebraska topography and the local systems employed.


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RE: Landscape problem for church

I really appreciate the discussion.

I can't over-emphasize the importance of taking pictures and documenting whenever any project is done whether on a home, church or community project. It really helps those down the road who purchase a home or take over leadership, especially after a period of time passes. In our case, I'm trying to put together the pieces of a puzzle that can't be seen.

FYI, when there used to be the enclosed stairway with the door at the bottom leading into the basement, there was a drain at the bottom of the stairway. No one really knows where the drain actually led to. I just remember occasionally using the old stairway and once in awhile there was water near the drain that we'd have to step around. So, when they closed up the stairway I don't really know what they did with that drain. But, as I mentioned we really don't have a moisture problem at the floor level in the church basement, it's more a matter of wall moisture and efflorescence. The church is on the top of a hill, so downward draining water is not an issue.

I may try to manually dig down as Yardviser mentioned just to see what I can learn about waterproofing. I know we don't have a sump pump.


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RE: Landscape problem for church

we don't usually use the paint on or laminate bituthenes. in its place mirafi is use. usually the g series.
so if you don't see the tar like paint, then look for mirafi ( google will help you see what it looks like )
It's going to be difficult on a site like yours to find the breach.
I might follow the efflorecence path by checking out the newest masonry that was done.
That's where you may find your breach.

PS - I'd suggest a tight line for your drain spouts to eliminate the runoff rain water from the roof.

Senor Bahia may have more info for you. He's worked on some large foundation projects .


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RE: Landscape problem for church

  • Posted by bahia SF Bay Area (My Page) on
    Fri, Sep 23, 11 at 12:22

You can't get follow up info from the contractor who sealed off the basement door? It would have been obvious at that time what waterproofing membrane and/or pipe drain at base of wall for drainage carry away was or was not existing. Also, if the work was done with a building permit it would have had both plans/drawings and been inspected for conformance. I'd start with these avenues before before digging, but digging all the way down to the base of the wall at the closed off doorway and seeing if a french drain line could be connected there along with entirely excavating against the wall so that you can install waterproofing and a drain line is really the only thorough day to resolve the moisture.
/efflorescence at the wall. Is the interior face of this wall concrete or is it framed out with wood studs and sheetrock? I don't think you are realistically looking at a cheap or easy fix in your situation. Responsibility would also follow back to who ever signed off on the work for the church, drainage and waterproofing concerns are an obvious and critical design element when you have basements below grade.


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RE: Landscape problem for church

Just to reconfirm I only meant an exploratory digging to start with, not an excavation...just to see what's there. Sometimes what's on a drawing (or in someone's memory) does not equal what's in real life. A small amount of digging will show waterproofing, or not.

d-d...how is Mirafi attached? And what keeps water from entering through it's upper edge?


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RE: Landscape problem for church

Yardviser,
Mirafi's attachment varies from substate to substrate, but for masonry you could use liquid adhesive, masonry screws and or even duct tape.
The drain rock and soil back fill keeps it in place against the walls.
Install it from the bottom up.
The top edge can be tucked into the masonry or a edging band can be applied.
Check out the specification sheets on their website for a more thorough understanding of how works.
I have a very old and cheezedoggy video showing a landscape installation from 2007 on Youtube. ( it was one of my first and few attempts at cataloging our installations ) On the video @ 47 seconds, you can see the guys installing the mirafi. They are about 12 feet down into a trench.
heres the link - http://www.youtube.com/watch?v=ZR7b_pn8k3g - sorry about the quality and the accompanying porn like music.


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RE: Landscape problem for church

  • Posted by bahia SF Bay Area (My Page) on
    Sun, Sep 25, 11 at 13:59

Projects I've worked on with habitable below grade construction usually combined bituthane applied to the concrete with Miraculous drainage wrap material applied over a protection board sandwhiched between the two, and all Downspouts tied together to take water well away from the building. Where the building is downslope of a hill, it is often usual to add secondary french drain lines away from and above the slope down to the building to capture subgrade water before it reaches the below grade wall. Use of protection board is critical to keeping a bituthane membrane intact and unbreached over the long term. Attempting to seal against moisture at the inside of the wall is usually less than successful, and does nothing to prevent dampness leading to dry rot and termite infestation of attached wood framed walls.


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