Basement Floor Issue

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Posted by: from Chilliwack
12/18/2020 at 9:05:51 AM

We have a 700 SF laundry room and 1 bedroom suite in half the basement. The main room is 320 SF. We put Dricore 2x2 panels in the main room and hallway to bedroom about 14 years ago and covered with wood laminate. We also put wood laminate down in the laundry room (it was free so I used it) right on concrete. The laundry room had a flood like 6 months after I put it down so all that laminate came up and we painted the floor and its been painted concrete since. The bedroom had 3/4 inch strapping nailed into the concrete with 1/2 inch OSB nailed onto the strapping with carpet over. That was put down 30 years ago I'm guessing, before we bought the house 20 years ago anyway.

Remodeling the entire suite and laundry now. Removed the older bedroom subfloor. Very Dry. No sign of moisture issues. Definitely could have left the subfloor but I ripped it up before I realized.

Removed the laminate from main room and hallway yesterday. Right away noticed lots of dark colour under the thin foam underlay. started pulling it all up and LOTS OF MOULD. Uncovered the whole thing and there was a couple of areas that I could almost put my fingers through the dricore. Pulled it up and there was thin layer of water underneath about 250 SF of the 320 SF room. The worst area (lowest spot of the floor) had at least 1/8 inch standing water in the concrete. The dricore in 90% of the room and hallway came up wet and mouldy. No mould on walls or mould smell that you would expect though.

I don't know what to think. I really want to believe that the water got under there during 1 or more of the 3 water escapes that I know of (or 1 that happened when tenants were living in there that I don't know of) and its been there ever since could never get dry because no air could get in. BUT it could also be water seeping up and accumulating. That would be the worst for me because then I can't trust putting dricore down again and not having same thing happen. The bedroom and laundry have no seepage issues at all. Very dry. It doesn't make sense to me that its very dry in bedroom with no seepage and 15 feet away its very wet but I don't know.

I could not tell by smell or walking on the floor that the subfloor has been soaked like that for ? 10 years since flood in laundry? 5 years ago overhead pipe drain pipe had a leak for some time before we noticed and we cleaned it all up BUT MAYBE we didn't know more water than wet thought got under the laminate? I don't know.

I want to cut some 1 inch deep channels in the concrete that would run to a sump drain I have in the laundry room floor and then seal the entire area with a good concrete sealing product and then lay the dricore and vinyl plank over top and not have to worry about it anymore. Also thinking about making a liftable 3 x4 ft section of the dricore and vinyl plank over that low spot so I can lift it every 6 months and dehumidy it and blow air in. Are those ideas dumb? Can anyone offer some advice here?

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Daniel from Landen Design Build in Okotoks
Date/Time12/18/2020 at 3:15:35 PM

It may be difficult to pinpoint exactly what your problem is without seeing it. As we are located in Calgary Alberta, and I am not sure where you are located the conditions where you live may be substantially different from southern Alberta where it is typically very dry. However the main culprit is probably some form of water seepage into your basement. It may not be readily apparent where this is coming from, but the soil surrounding your home will have some form of moisture in it, and this moisture will want to make its way into the foundation. This could be caused by not having proper weeping tile drainage or any other number of issues. You mentioned that you have sump pump, if this sump pump (pit) is installed substantially lower say 24 -30 lower than the basement slab floor, and assuming that the basement slab floor has been poured over 6 or so of washed gravel base as is normal , then this gravel base should allow drainage into the sump pit, where it can then be pumped out. Where your suggestion of cutting drainage slots in the slab would not be required, nor would an inspection spot, as you could very easily check the sump-pit to see if you have water collecting.

To eliminate your problem, you will need to confirm where water is leaking/seeping in, and stop the water intrusion to prevent further occurrences. Many seepage incidents are caused by a combination of poor exterior grading and drainage.

The Dry-core subfloor material you have installed in your basement is a good product to keep your finished flooring dry and make the finished floor warmer; however it does have limited abilities to manage water. The very slightly elevated plastic surface on the underside of this material will provide a small air space to allow some air movement, but may not be adequate if you have a larger amount of moisture to get rid of or if other water leakage occurs.

Most manufacturers of this style of subflooring suggest additional vents be cut into the surface of the subfloor at various spacing (similar to a standard 4x10 Heat vent hole). And, best placed mainly around the perimeter of the subfloor, cover these vent holes with typical heating registers.

Also check to see that eaves downspouts are bringing rain water out and away from the foundation, this could be a problem that could be solved easily, extensions should be installed 3 meters away from the foundation to divert water away from the house. The majority of moisture intrusion that we come across is from improperly installed downspouts that are terminating right at the house corner.

Greg Genereux CEO Landen Devlopment

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Date/Time12/18/2020 at 9:43:42 PM

Hi David,

Please call 604-306-7505 to discuss details. We can review this if possible to send us some photos and try to understand the issue better. It could be envelope or drain tile issues as well as a low point in your slab which collects all the water.



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David in Chilliwack
Date/Time12/28/2020 at 9:01:00 AM

Thank you very much for taking the time to provide info and insight. As soon as I read the 2 posted replies I called my contractor friend and he came over - 1 day later I had 2 big sections of wall off the concrete and exposed 1 crack and some weeping tie holes. Xypexed that all really well and scheduled a complete dig of foundation walls this summer for new proofing outside and drain pipe with outdoor sump. Needless to say my $4,000 remodel went to $20K overnight. Oh well. thanks again.


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