I am planning out building a large garage/shop space on my property in Hopkins, Minnesota. The garage will be built into a hill and the rear of the garage will be about 6′ underground. The soil in my area is full of clay and currently have a tuck under garage that has significant issue with moisture and humidity in the Summer. The architect I am working with suggested back filling along the block walls of the structure with gravel and installing drain tile to day light to help to keep things dry in addition to insulating and waterproofing the exterior of the block walls. The contractor I have spoken to says that that will draw more water in to the garage and make a larger problem. Anyone have experience in this area?
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31 yrs ago we built our dream home. A carpenter for 15 yrs and at that time working union commercial, so consistent work and early starts gave me a year and a half of afternoons and weekends to work on it.
We planned as we paid off the land and one thing caught my attention because we planned our house built into the hillside.......heavy clay soil.......passive solar orientation.........and that clay.
I found what at the time was called warm and dry insulation drainage board by Owens Corning. 2” thick, r-value about 10. With the proper block water proofing coating, this rigid fiberglass board over it down to the footing with perf. drain pipe alongside the footing running around the house to daylight and down the hill. All stone backfill, no dirt at grade.
No water entry anywhere, no moisture or mold even under the dark stairwell to the second floor. We live on both floors, this isn’t a basement.
That clay. Around here there are numerous Foundation problems as the clay shrinks back when in a dry spell, leaving a void that’s easily filled with water during large rain events. Clay expands and pushes in some foundation walls.
Not in this house, 31 years running.
Keys we used, lateral reinforcing in the block courses, rebar when needed, large coating, waterproofing, fiberglass drainage board, pipe next to the footer, and stone backfill all the way up.
Had to go across to Canada to pick up the drainage board as at the time it wasn’t stocked here in NW Ohio. Created a bit of problem as the customs couldn’t find it in their book.......should have just called it insulation
Hope some of this helps and the best of luck.
Wow. Super helpful and this sounds very similar to the same plan as mine. The building inspector agreed with the architect, and the builder says that other contractors agree with him.
Well, that was our experience and being in the trade now for over 45 years I’m sure I haven’t seen it all nor know the vast expanse of knowledge available.......it worked for us. We took 7 years to pay off the land and in that time we studied quite a bit. I’m sure I would have done some things different and technology has certainly improved over time.....but all in all we’re pretty pleased.
My grand parents emigrated to the iron range, now they had winters! Where are you in Mn?
In a suburb of Minneapolis in central MN. A little warmer than the Iron Range!
Agree with all of this. I would reach out to a good waterproofing company as the technology improves all the time. Beyond basement waterproofing below grade there are things that can be done on the surface as well. If you can get all downspouts in pipe underground and diverted to daylight that will help a lot. Also, try designing your roof pitch to allow water to travel off the roof to areas of the lot that will dry quickly. Also, do some research into a French drain. I had a project once where the owners property was on the downside of a large hill. All the neighbors lawn watering flowed down hill, it was a mess. Previous to my arrival they had multiple water proofing companies out to install the best and latest basement waterproofing systems. They helped, but they still had issues. It wasn’t so much the ground water entering, but the surface water. We installed a French drain right at grade at foundation wall. Also installed what we call a dry river bed. Basically, up slope and parallel from the foundation wall we dug a troff on grade the full length of foundation wall, about 20ish feet away from foundation. We then lined that with a good quality landscape fabric that slows water penetration, but also allows ground to breathe. Installed a 6” perforated pipe with river rock on top of that. That basement is dry to this day and the owners think I’m a genius.
Thanks, good info.
One added and possibly passive idea is grading. A swale up above on the grade can direct surface water and slow saturation, helping out the area below. Being careful so the direction doesnt cause a washout. A good experienced excavator is worth their “weight” and knowledge. We got lucky.