Last week we had to do basement waterproofing on my investment property. We dug two sides all the way down to the footing. After backfill I noticed the driveway wall had about a six foot horizontial crack that opened up about 1/8″ to 3/16″.
Can I just tuckpoint this? The wall does not have a big bow or anything. Should I be worried about this? We havent done final grade yet so we will still be stacking a little (about a foot) dirt in the same area.
We are not pouring a driveway on the fresh ground cause it would just be wasted in a year.
Replies
You might offer more information.
What proximity does the driveway have to the area you dug up? How deep did you dig (how far down to the footer?)? etc.
Life and suffering are inseparable.
We dug all the way down to the footing. The driveway is right on the side of the house. We wont be placing driveway on top though. we're only going to the front of the house.
The crack is about half way up the wall. it was allready there but is more pronounced now.
what kind of soil is the backfill and is this a poured re-inforced concrete wall, or a block foundation? I'm suprised that hasn't been asked yet!
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I guess those would be good things to know. Soil is clay and the foundation is block. the gap is open about 1/8-3/16 and runs about 6 feet.
The clay soil is very expansive. TYhe waterproofing you just installed will (hopefully) keep moisture out of the basement, but the same moisture will cause the clay to swell and push against the foundation wall. You should have used a select backfill material.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
So what are you telling me Ed? Should I start diggin'? Is there anything else I can do? The area has not been finish graded yet, but has seen some traffic.
You should definitely start digging. You should never use clay against a foundation for two reasons. One is that it will not let water follow to the perimeter drain
The other is that when it holds that water, it will expand. That means your crack will only get worse no matter what you do to repair it unless you replace the clay with gravel so it can drain.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Thats not fair. The clay was there. Its not like I brought it in. How far would you suggest I dig? Do I need to go all the way back to the footing?
This foundation is going to cost a ton. Wish I didnt care sometimes.
If I change out the clay, do you think i'll be ok as far as the crack, or will I have to straighten the wall too?
Edited 10/2/2005 9:25 pm ET by MSA1
Yep, you need to go all the way back down to the footing, and about 3-4 feet wide. Hey ... look at the bright side ... it's not compacted yet!
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Fair???Is it fair to build on a foundation that will continue to fail and sell it to someone?it is simply good building practice to do things right. We have bad clay here too, and because gravel is not native to this island, it comes by ferry and costs at least $28/yd for inch-minus to th esite, but if the client is getting a cellar odf stemwall crawl space, they get proper drainage and a soil that will not destroy the wall.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I know, i'll be making some calls on monday. Just kidding about the "fair" remark. I would never feel right selling a house that was less than the best product I could provide.
I just hope I can swap the fill for under a grand. I got a great deal on this house but the budget is not bottomless.
No.
Call a structural engineer for the fix. We have done a number of these.
Sorry.
carpenter in transition
Nothings cheap. If it wasnt for the crack you wouldnt notice any of the bow. Any way to just remove some dirt and fix it (relatively) easily?
unless you put a membrane waterproofing on the wall, it has been compromised at the crack and can/will leak.
i am guessing that you probably had a water problem to begin with, otherwise why would you dig up the foundation to waterproof it ?
at this point,
the wall repair involves either shoring the structure and replacing the wall
or
installing reinforced concrete block pilasters or steel angles/channels/vertical I-beams on the interior of the wall at a specified spacing. the structural engineer can specify this for you. we have done these several times.
based on my past experience, if you already have a water problem, you should rip the wall out and rebuild it properly. the fact that it cracked during backfill suggests that it may not have been built properly. the new crack will just add to your leak headaches.
i'm a bundle of joy, aren't i ?
carpenter in transition
The wall has been parged, covered w/plastic, & rigid insulation. The drain tile was also replaced. I've talked to an excavator about removing the clay and installing sand. Hopefully this will keep it from getting any worse.
I'm going to have it checked out by someone that knows better than me about foundations. It really doesnt look too bad to me, but I am going to get a second opinion. Not that I dont appreicate your opinion but you havent seen it and I cant figure out how to post pics.
BTW it rained buckets today and not a drop in the basement.
Edited 10/3/2005 9:19 pm ET by MSA1
covered w/plastic
plastic, like poly or polyethylene ?
for a foundation waterproofing membrane ?
seriously ?
I've talked to an excavator about removing the clay and installing sand. Hopefully this will keep it from getting any worse.
you're headed down the wrong path. don't remove the existing fill material until you have a plan in place for repair. if you want to keep it from getting worse, then shore it from the inside with properly sized framing materials for now.
assume you do nothing to repair the foundation. in the spring, let's assume we have heavy rains which cause overly saturated soils. if your foundation wall were to collapse, what would happen ? is it a bearing wall for your floor system ? if so, chances are it may take part of the upper structure with it.
do you have tenants living in the structure ? are you willing to put them at risk ?
please, hire a PE to review this.carpenter in transition
plastic, like poly or polyethylene ?
for a foundation waterproofing membrane ?
seriously ?
Tim, 6 mil poly's precisely what we use on our underground houses. Works like a dream. We extend a poly umbrella (multiple layers) out from the perimeter, ideally 20'. Dry dirt on the outside of the buried walls is necessary for our heating/cooling systems to function well, as is ground contact. Poly is all that's needed, with reasonable site selection.
Several yrs ago I poured, against my better judgement, a 6"x8' tall wall for a friend. He was so cheap he also skimped on the rebar. And then backfilled 4 days later, 7' high on a walkout basement. Surprised me that he only got 1 good-sized vertical crack. Wasn't a house, but his office is still sitting on that wall. It did get a good footing with multiple rebar going into the wall.
PAHS Designer/Builder- Bury it!
tom
i think we're talking about apples and oranges in both of your examples. in your case, you are creating an umbrella effect over the roof + 20' in all directions thereby diverting most of the surface water away from the foundation.
in this case. we have standard construction, full basement, with a concrete block wall that has pre-existing leakage problems. the homeowner installed poly against the block with styrofoam. can 6 mil poly stop the water flow ? yes, but other than the styrofoam, how are you going to prevent damage to the poly ? the poly moves during the backfill process, rubbing against the coarse textured block. more importantly, the poly was only installed on two walls. how are you going to terminate and waterproof the poly vertically at two locations, on top of the footer, and then at the top of the wall at grade ? the poly must be terminated at the top in such a way that there is no UV exposure. to spend so much money on excavation for the sole purpose of waterproofing and then use poly as your membrane is a poor decision imo.
as far as your friend with the 6" wall, his wall is poured concrete with some rebar and most importantly, a vertical crack.
this wall is concrete block, no rebar, and a horizontal crack in a mortar joint with an open gap of 3/16". over the 8' height of the wall, this could translate to 1/2" to 3/4" deflection in a wall with no vertical reinforcement and little lateral strength.
carpenter in transition
I didnt do the repairs. The company that did the work gave me a 35yr warranty. They first parged the wall w/wetstick(tar) then the poly then the insulation.
As i said before I am concerned about this problem and am taking action (second opinion)to get it fixed.
No of course I would not want to sell this property to anyone and have the foundation fail. This is a joist bearing wall so yes there would be a great deal of damage should it fail.
Out here in earthquake country, the seismic retrofit guys use a two part epoxy injection product to repair footing cracks. I'm not saying that it's what you need, you need an engineer to visit the site for that. But it is an item you should be aware of.
-- J.S.
Thanks for letting me know about the epoxy. It may be useful.
Is the basement unfinished? If so, you could fabricate an "I" beam with plates on either end, and install it vertically against the wall, bolted top and bottom as insurance. There probably isn't a block foundation that doesn't have some sort of crack in it. Better backfill, with controlled compaction would be a wise move.
Thats a good idea. Like I said i'm keeping an eye on it and if theres any movement I think i'll give it a try.
Tim, in your enthusiasm you missed the point.
Poly, if protected, is a perfectly acceptable water shield. If MSA1 would use it the way we do, there will be no wet fill on the outside of his wall, nor any fear of expansive clays, if in fact he has any. This isn't a problem for all clays. A high water table at his location would be more difficult. Poly combined with shallow footing frost protection insulation would be the best of all worlds. As he's talking about excavation, there is presumably no landscaping to prevent installation. We use carpet discards to protect the poly. Works like a dream, whether against rough concrete or rocks. Your concerns about poly are easily taken into account.
If you want, you can make an argument against all forms of waterproofing. Far as I know, they all have to be properly installed to succeed. Poly's no different in that respect, just immensely cheaper.
The reason I mentioned the concrete wall was to point out that even though it's decidedly substandard, it's working. I've seen many block walls with worse cracks than MSA1 describes. None have failed catastrophically.
My mother's Michigan house, near West Branch, is unheated winters. Her block foundation moved 12" into the basement. Also clay on the outside of the walls. The contractor involved simply laid another wall inside the first one. House is fine. Never endangered anybody. Original block was laid early 40's. House is a frame 2 story. Continues to be unheated winters. Frozen ground was the problem there, not expansive clay.
Locally, I speculated on a masonry foundation house with a gaping hole. The 8' wide non-support caused the back door to bind. This was a wall supporting the rafters. There was serious sag. Some jacking in the basement and a new wall solved the problem. Other than cosmetic cracks, no lasting problems.
Whether MSA1 has a real problem neither you nor I know. I understand your continual urging for a PE. If you'd dealt with the PEs in my area you might very well have a different take. I've dealt with 100% of the local talent. It's very disappointing. Certainly not a panacea.
Forgive my memory, but are you transitioning into becoming a PE?
PAHS Designer/Builder- Bury it!
Your mothers house sounds just like what i'm working on. Built in 1940, in Ferndale (MI), in clay. Its reassuring that if her wall didnt fall, at least I dont have to worry about going into work tomorrow to a collapsed house.
When I was younger, I rented a big two story house in Detroit with a brick foundation. That wall was bowed 21/2"-3" and it was fine. Still standing today.
Hope I haven't muddied the waters. Ferndale I don't know, nor Warren, for that matter. I mentioned West Branch solely for clarification after looking at your profile.
My modest experience with clays is Denver, with extremely expansive clay (bentonite, which I've used for waterproofing- fantastic stuff), near West Branch with gray clay that isn't expansive, and our Va red clay which also isn't expansive. Please don't assume that I am a clay expert. Bentonite I understand, but that's about it.
Notice that I didn't offer any advice to you, simply offered conflicting ideas to those proposed. That's because I really don't know your local situation, just like everybody else here. Consensus was to bring in a PE. Might very well be worth the money to you. Or not. Clearly, you would do well to bring in someone familiar with your construction and your clay.
One thing that seems obvious to me is that predictions of cataclysmic failure are usually overstated. No guarantee. Sometimes the advice here is worth what you paid for it. Mine incuded.
Good luck.
PAHS Designer/Builder- Bury it!
I brought my foundation/cement guy back yesterday. He's very familiar with ferndale. His suggestion to me was to leave it alone and tamp the ground and run the driveway in before winter.
He suggests this and proper grading will keep the water away. he also said that the wall will be fine once tuck pointed and that it more than likely happened on back fill and not from the clay expansion.
Without knowing any more than I do about your local situation, I'd certainly agree with your foundation guy. Controlling surface water is usually the main thing.
Clearly, your job then is to monitor the crack. Like I hope the guy with the 6" wall is doing. No news is good news eh?
Good luck.PAHS Designer/Builder- Bury it!
I'm watching it constantly. We've had alot of rain since I first noticed the crack and I havent noticed any more damage so I think the foundation guy is right, it happened on backfill.
Sounds like you're set. Ain't BT great? Lots of opinions. Often, none of them wrong. Lets you pick and choose.PAHS Designer/Builder- Bury it!
Yeah, There's alot of knowledge here and I dont mind using it. Looks like it should be fine.
there are times when i sense that someone is looking for a potential "quick-fix" to a problem that could ulitmately end up costing them in the long run. my response in these cases is to be as firm as possible in encouraging them to consider otherwise. that's exactly what you are seeing here.
i understand your disappointment with your local talent. i wouldn't grade all of ours with an 'A' either. nonetheless, my recommendation to a person 1500 miles from here is get professional help from someone qualifed. in this situation, i stand behind my suggestion that they seek the help of a PE.
carpenter in transition