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Can Footings and Exterior Walls Be Left Exposed for Remainder of Winter?

scottwoodward | Posted in General Questions on

I’m about to put up rigid, R-10 insulation on the exterior walls and am thinking about the next step of backfilling. Unfortunately, I’m at the point where I don’t completely trust what my dirt and foundation contractors are telling me.

The original plan was to use fill material that’s on site, which is mostly sandy, typical New Hampshire soil (very little, if any clay). At this point, however, we’ve had more rain than snow and warm temperatures in the last week so everything on site is super wet. I’m loath to truck in more fill material as I just got the bill for material trucked in earlier.

Can the footings and exterior walls be left exposed if I don’t start framing until spring? Are there ways to protect the footings and walls without backfilling? (certainly, the rigid insulation will help, but then that insulation would also be exposed).

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Replies

  1. Expert Member
    Armando Cobo | | #1

    Your pics of the cleaned foundation looked great. After applying liquid flashing to the stubs, as mentioned in the other thread, I would leave the foundation alone till you have good weather to backfill, and I wouldn't install the insulation yet. Exposed concrete will not hurt, but make sure you have good drainage away from the foundation. No need to rush.

    1. scottwoodward | | #2

      Thanks Armando. So, so long as I get my perimeter drains in place, it's okay to leave the walls and footings exposed? I was worried that even though the footings are at the 48" frost depth that the footings could be susceptible to freezing and heaving. For what it's worth, while I was prepping the walls for the insulation, I noticed that there's a good inch to two inch ice around the footings on top of the gravel that I laid for the perimeter drain, but underneath the ice there's flowing water.

    2. Expert Member
      Armando Cobo | | #5

      As long as you have full gravity drainage to one side of the lot. You don't want water to pool at the footings.
      There's that little thingy Charlie mentioned, climate zone stuff... I agree, laying straw down is a good idea. I keep forgetting I'm not in Kansas any more.

  2. Walter Ahlgrim | | #3

    It is risky to back fill before the floor joist are in place the weight of the could crack the concrete without the support the joist provide.

    Also try to keep the heavy equipment back as much as is possible.

    Walta

  3. Charlie Sullivan | | #4

    Being sandy, not clay, I wouldn't be nearly as worried about it being wet as I would be with clay soil. But it being wet will make Walta's concern about cracking without floor joists a more serious concern.

    But then freezing and heaving under the footings is also a concern, even if not an issue in Armando's part of the country.

    You might consider getting straw or even wood chips or leaves to temporarily cover your footings, to insulate from to prevent freezing without the weight of the web back fill.

    1. scottwoodward | | #6

      Thanks Charlie, Armando and Walta --

      It seems abundantly clear that the perimeter drains need to be finished to keep water away from the footings. The good news on that the gravity/slope for the drains is working fine, but because I don't have the front perforated pipe and solid outlet pipe in place yet, the water is pooling where the water will eventually be draining out through the pipe. We've got favorable weather for the next handful of days, so I'll get the perimeter drains finished early next week. All the ice is now out of the hole. Once the water is out of there, perhaps it would be a good idea to get some straw on the footings (I saw that one of my neighbors who only did the footings this year for his new house just laid straw on top of his footings).

      With respect to movement of the foundation, I should mention that the slab hasn't been poured yet. Does that make any difference with respect to joists? My foundation guy says I need to get the sill plate installed to keep the foundation walls from moving, but that's different from putting in the joists. I'm not sure how the sill plates alone do anything to keep the walls from moving, unless he means movement within the line of a single wall. It may be a throw away cost, but I may just do a temporary solution with temporary sill plates and cross pieces.

      1. Expert Member
        Malcolm Taylor | | #7

        Scott,

        Isn't this the garage we discussed in the other thread? I see from the photos there you have already backfilled inside the foundation walls, so Walter's concerns about lateral movement aren't a worry. Not sure why your contractor wants to install the sill-plates. They add absolutely no strength.

        Whether or not the exposed footings will heave in cold weather is an open question. It's certainly risky to leave them exposed, especially if there is water pooling. Temporary insulation as Charlie suggested might be your best bet.

        1. scottwoodward | | #8

          Hi Malcom,

          Yes, that's right and that's also correct that the inside of the foundation has been filled with clean fill that was compacted at 8 inch lifts. I'm not sure why the foundation guy wants to put the sill plates on too. I'm not getting what that would accomplish.

          There's about 6-8 inches of stone underneath the footings all the way around the perimeter of the foundation. The only ice that's formed so far has sat on top of the stone. Still, I'm definitely going to get the perimeter drains done. Sounds like there's not really any risk backfilling around the exterior of the foundation either with the inside already filled and compacted?

          1. Expert Member
            Malcolm Taylor | | #9

            Scott,

            No risk at all.

  4. Expert Member
    Zephyr7 | | #10

    Part of the purpose of crushed stone under concrete things is to provide a layer that drains water away, which helps to prevent issues with freeze/thaw cycling under the concrete. I do agree that some temporary insulation probably isn't a bad idea though for a little extra insurance. I also agree that getting the footing drains done is a plus -- the goal here is to keep things as dry as possible: no water, no ice, no freezing concerns.

    BTW, I would NOT install rigid foam on that foundation wall until just before you backfill. UV exposure will degrade the insulation, so you don't want to put that insulation up until it has some protection from direct sunlight.

    Bill

  5. Trevor Chadwick | | #11

    15 years ago or so, I was helping a friend get ready for his mod build. Walk out basement, 8" thick poured foundation walls. no backfill, no slab. There was a hold up with the delivery of the house, and by time it came, we had gotten a fair amount of cold weather. The frost had gotten deep enough to heave a section of the wall up around 6". over a doorway
    He was "lucky" enough for it to settle in place in the spring, but it put the project back months.

  6. scottwoodward | | #12

    Thanks again for all the input. Very helpful. The fill material that's available on site is dry, despite the wet winter we're having. It's sandy soil. I think I'll be in good shape with either of two plans with the perimeter drain as a constant in both plans -- either insulate the footings with hay and cover for the remainder of the winter or backfill with the insulation on. We've got more favorable weather ahead this week so should be able to execute on of those plans.

    Happy new year all. Much appreciated.

  7. Allan C | | #13

    You learn something from all these Q&As. I was wondering why a new house in progress in my neighborhood stopped with the floor joists and housewrap over the subfloor. Builder plans to leave it over the winter and the joists support the concrete walls when backfilled.

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