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Under construction – How bad is my foundation drainage?

qofmiwok | Posted in General Questions on

   I’m hoping to get some input.  My house under construction is in 6B and the contractors didn’t follow the drawings. 
Footings are 5 or 6′ deep due to frost line.

   The main house foundation is ICF block with a waterproofing membrane and drain board with filter fabric.  There is a footing drain, and it was supposed to be backfilled with gravel surrounded by the filter fabric (the “burrito”).  Instead of backfilling with gravel, the contractor used dirt.  He said the geotech engineer was onsite and told him it was okay.  I don’t know yet if the burrito was done. 
   I know that if you have filter fabric, it is okay to backfill with dirt, but was planning both as belts and suspenders.  I have been obsessive in my design about drainage because we have an underground stream during high snow-melt years, and I am massively mold sensitive.  But I suspect this is probably okay even with the dirt fill.
   But I’m not sure how well compacted it is; I told them several times how important the compaction is to me so the dirt near the house doesn’t settle and drain toward the house.  Also the dirt has a lot of big rocks, up to 10-12″ etc. Is that good or bad for compaction and drainage?  

   The next issue is we have a hobby room off the garage which is slab on grade.  We’ll spend a lot of time in there so it was supposed to be built as “good” as a house, not built like a garage.  We bought the same R7 windows, have  a zehnder ventilation loop, exterior insulation to prevent condensation on the sheathing , etc.  In this case the foundation is poured concrete plus waterproofing membrane and 3″ un-taped EPS.  The entire space under the slab/vapor barrier/sub-slab insulation is filled with gravel.  But the exterior has no drain board or filter fabric, and they used the same dirt to backfill instead of gravel.  Does the EPS foam there help in some way to create a drainage plane and relieve hydrostatic pressure, or is it just going to get soaked leaving water right against the membrane? 
   In addition I have learned there is no footing drain there like I expected.  I haven’t studied slab on grade as much as crawlspaces and basements, but I think they still should have footing drains, right?  Maybe this whole thing will work though because it will only be wet for a few weeks each year and then will dry?


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  1. walta100 | | #1

    The first question in my mind is who is the general contractor for this house?

    Was this change made by a sub without notifying the general contractor or did the general approve the change?

    If you are playing general contractor you better get your stuff together because this sub is walking all over you and if one gets away with it they all will take advantage of you.

    If you have a general have him deal with the sub and you stay out of it other than demanding you get what was bid at the price agreed.

    If you are playing general demand that he, do the job as bid at the price agreed nothing less.

    If the sub can convince the engineer to provide a stamp set of drawing for the work as preformed you will accept his work with a 25% discount.

    Do you have the stone to throw this sub off your job, find another sub to replace him and let the first sub know he will be paid his bid less whatever his replacement happens to charge you?

    Please tell me you footing drains do go to daylight.

    My general would not allow any backfilling before the first floor joists and decking were installed and he delayed that work for some time (2-4 weeks) to allow the concrete to gain enough strength. Note no heavy equipment was ever allowed within 6 feet of a basement wall. All this in an effort to lower the risk of cracking a basement wall.


  2. qofmiwok | | #2

    Hi Walta
    I have a GC who is supposedly one of the higher end ones in town. His employees were involved heavily with this process and onsite with the sub almost every day working closely. I would answer that the GC approved it all. Frankly my mind is blown that they are not following the drawings or getting permission from the architect to deviate. So yes, I know they are responsible for that. This is just a horrible time to build a house and everyone is too busy and making mistakes (there were others before this that I caught in time to correct but it delayed the schedule which is causing other problems.) Other builders in town are booked 5 years out. So I'm having to choose where to pick my battles.

    Also in the case of the footing drain in the hobby room, that is not in the drawings so is on my architect. So I'm gathering info on that one. Do people usually put footing drains around slabs? Around garages? I would at least feel better if it were gravel backfill as designed, since there's no drainboard. They will dig it out and put gravel since that was in the plans. But I'm trying to figure out if I also need to add a footing drain there.

    There's not enough slope for my footing drains to go to daylight but they are going to a large deep dry well. And I recently decided to add a pump to the dry well (in addition to the sump pump inside the crawl).

  3. Expert Member


    I'm a bit unclear from your description whether there is any drain-rock around your perimeter drains, and the problem is that it didn't extend up, or of there was no rock used at all.

    If it's the former I wouldn't be too worried. I also wouldn't be too upset by the lack of perimeter drains around any slab that as above grade as long as there was no chance of surface water accumulating.

  4. qofmiwok | | #4

    Yes, there is good draining gravel around the perimeter drains of the house, and the pipe and some amount of gravel is wrapped in filter fabric. I'm just not sure the filter fabric came all the way back up and over to the house like it was supposed to.

    Since the slab is only likely to get water from below, not surface water, then it can drain through the 5' of gravel under the slab even if there's no gravel on the outside. Is that your thinking? Or would gravel still be better on the outside even if there's no footing drain below it?

    1. Expert Member
      MALCOLM TAYLOR | | #5


      And long as the water under the slab can't get up to the underside it isn't a problem. In areas with high hydrostatic pressure where the water might build up until it was in contact with the underside of the slab, it's best to run a drainage pipe connected to the perimeter drains into the sub slab-gravel as an outlet.

  5. walta100 | | #6

    Have a sit down with your GC and express your concerns about how the plans are being ignored.

    Do not tell the GC how you want the problem fixed. Let your deafening silence fill the room and force him explain to you how he will make it right.

    I would not be surprised if what the sub did is your contractor’s standard practice and given their history of building dozens of dry basements combined with his knowledge of the locale soil his SOP may be just fine.

    When I built my house I came to understand that I had just married my GC for the duration of this project. Divorcing him is an unthinkably completed and expensive prospect to contemplate. I am not saying to be a door mat but this is the last person on earth you want to make into your enemy. Trust that you made the right choice when you picked him unless and until proven otherwise take his side. All I can say is hang on there is a long and bumpy ride ahead of you. You will have thousands of decisions some big many tiny most are not in you’re drawing every one of them will have a deadline. The hardest part for me was spending so much money in such a short amount of time.


    1. qofmiwok | | #7

      Thanks. I totally agree, that's why I'm focused on what is the right solution; what the risks are with what they did instead of what they were supposed to do. Not how to argue with the GC.

  6. walta100 | | #8

    When I read your post it is not clear to me you know exactly what was or was not done and how.

    Leave open the possibility you misunderstood and or the sub misspoke.

    First you need the GC to tell you what was done and how? If what was done deviated from the plans? Was the deviation with or without his knowledge and or approval? Assuming it was a deviation without his knowledge this should but you and GC on the same side of the argument try to keep it that way.

    Get THE GC opinion, if what was done will work or not and if the engineer will draw plans for what was done and put his stamp on it. If he will not put his stamp on it that is very clear evidence what was done is not going to work.

    If whatever was done is deemed acceptable, point out that the sub saved considerable amounts of labor and materials by deviating from the plans. Now let’s talk about the discount you are due.

    If somehow you total misunderstood and the story changes to that he back filled with clean rock for 18 inches, consider insisting on having the load ticket from the quarry emailed from the quarry to you directly. The record should show the number of pounds of clean rock being deliver to your address on the day in question by each truck. I doubt a quarry will not fake this for their best customer. This is a lose lose position for you If the ticket shows up you are proven to be a crazy person that doesn’t understand the English language or you prove your GC is a bald faced liar and the project is doom to fail.


  7. charlie_sullivan | | #9

    Your story brings back painful memories of working with a GC who didn't hold his subs to high standards, to the plans, or to specifics that we agreed upon in writing. Your comment about "choosing your battles" makes sense; on the other hand, now is the time to establish expectations that you have specific plans for specific reasons and you expect those to be followed. In particular it may be necessary to establish an expectation that there will be financial consequences, not just a heartfelt apology. Once that is clear, you can be more selective about your battles to choose.

    You do also want to be clear that you are willing to pay for good work. You want to be emphasizing that your goal is to make sure the work is done right, not that you are looking for an excuse to nickle and dime them. Maybe someone will have suggestions on how to frame that in a way to gives them something to work towards. A bonus if air tightness beats the spec by 30%? I don't know.

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