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In fact, it's one of the solutions that I recommended on this page, which deals with my damp basement problems.
I opted for that strategy because it suited the three types of foundations that my house was built on:
1. The main building, dating back to the '50s, has a full, unfinished basement of parged concrete blocks. Due to a few cracks in the walls and a lot of seepage, it used to be quite damp, as you can see from this picture, taken shortly after I bought it.
2. The sunroom/office addition, on the south side, was built in the Seventies. It has only a concrete slab under it, which, as we discovered when we rebuilt the floor, had a water seepage problem that was serious enough to force us to rethink our whole approach before proceeding with the expensive spray foam insulation project.
That problem consisted of rotten floor joists due to water damage on the whole length of the south side, as you can see from this photo.
The solution to this damp basement problem will be treated in detail separately. It includes improving yard drainage combined with the installation of an interesting French drain system designed for preventing future rot and deterioration of all the new work.
3. The third basement is a crawl space with a dirt floor under the north side, the kitchen-dinette addition. It dates from the seventies as well. As you can see from this picture, the foundation was totally exposed, down to the footings.
Improving yard drainage was a secondary issue here.
First, I improved the drainage at the footings with a foot of crushed rock. I hadn't yet installed eavestroughs on that section of roof, and I didn't like the way the rain splashed the foundation.
Then, we insulated it on the inside with spray foam and installed a vapor barrier on the dirt floor.
But now that I had moved into the house I wanted more than the absence of a damp basement: I wanted to eliminate the frost-induced heaving problem that we encountered last winter, which at times twisted the door frame to the point of being unable to close the door. I wanted to accomplish this without creating a moisture problem in that crawl space, which, until now, had been remarkably dry.
After much research, I settled on the following strategy: combining spray foam insulation inside and burying the foundation outside. I hoped that this would prevent the temperature extremes that had caused the heaving problem.
This is the step-by-step report of that project.
PREPARING FOR THE "BURIAL"
In anticipation of the earthworks to come, as part of the yard drainage improvement project, the builder and I did a lot of planning.
First, we applied two coats of black waterproofing compound, then we stapled and glued a strip of black plastic 12 inches wide overlapping both the house wrap and the foundation, before applying the siding; it got further fastened by the wood trim at the bottom. This black plastic is of a type designed for applying on the foundations of minihomes around here, and it's quite expensive, but I had some around that we had removed from the sunroom/office reconstruction project.
As you can see from this other picture, I had another problem: creating a patio outside those new patio doors. Decks are very popular (even in this climate where no one uses them!); they are also awfully expensive and not very green, what with all the wood being used (toxic, treated wood, for the most part -- "certified" wood does exist but not in these parts, where the main industry is... forestry!)Besides, when I bought that house I always imagined it with a nice terrace at the back, paved with flagstones that had fragrant thyme growing between them. Well, it just so happens that there's a fabulous natural slate quarry just five minutes away, owned by the one of my neigbors. Talk about green! A minimum of transport, a 100% natural material requiring no energy whatsoever to process.
I consulted with a local landscaping contractor, who immediately vetoed my suggestion of creating this terrace with dirt. "What happens with soil", he said, "is that it swells with water, which expands when the temperatures drop, and this will push against your foundation." What I wanted, he said, was good old sand.
Sand! Not only that, but the sand pit was a mere 500 feet away, as the crow flies; it's located directly behind my property, on the other side of a small woods. Being green was never this easy.
Here is the sand pit in question.A SMALL DIY DRAINAGE SOLUTION
All around the perimeter of this house, the soil had settled, to the point that it now drained towards the foundation instead of away from it. It was imperative to take advantage of these earthworks to correct that situation.
Earlier in the year, after my neighbors disturbed the soil by drilling a new well, during heavy rainfalls my basement would get wet. To correct this, I had my helper slope the dirt up against the house, creating a small ditch. I also added a window well with a clear plastic cover to keep the water away from the well. He also created a small dam with stones. This cleared up the problem. I have a dry basement again, but until the grass grows back where the digging took place, there will be the danger of the dam breaking and I could get some seepage again. (Vegetation absorbs the rain and prevents erosion.) To be safe, as soon as I get a chance, I will put a row of flat rocks or pavers against the house, to anchor that dirt, and when I have access to the shale quarry I will strenghthen the other side of the little ditch with a few flat stones stacked horizontally.
EARTHWORKS!
Now the time had come to create that terrace. I should have been a boy, I get such a kick out of bulldozers! First the sand was dumped from the "Big Old Truck" – two loads at a time, for a total of eight loads.
Before moving the sand, the rainwater downspout had to be adjusted, as the ground level would be raised by a couple of feet.
The downspout was disconnected, and the pipe (which takes the rainwater underground across the yard to a dry well) was covered with a can, to keep the sand out. A second downspout just had to have the bottom elbow removed.
Then I watched as the big machine (spewing quite a bit of diesel smoke, alas!) pushed the sand against the house ever so delicately, and adjusted the grade little by little. Murray, the machine's owner, has been at this for fifty years or so, so it's not surprising how precisely he manages that noisy monster.
A bit of shoveling here and there, a final adjustment to the downspouts, and it was time to put some gravel over the sand on the east side, where the driveway is located, and slope that down and away from the foundation. (Sand is too slippery to drive on and this gravel creates a good base for other driveway finishes.)SLOPE DESIGN
As you can see from the photos, there is a very progressive grade sloping away from the house. Enough to keep the rain running away from the house in all directions, Murray said, but come spring, I may have to adjust the slope and will do it by following the very clear and simple directions for slope design that I found in this About.com article entitled How Much Slope Is Needed In Land Grading Near Foundations.
NEXT STEP: LANDSCAPING FOR BEAUTY
AND FOR FOOD
Winter is upon us; the final design and landscaping of my terrace will have to wait till spring. Sand is very light and easy to shift and I'll be able to do it myself.One thing is certain: I know where I'll get my green tools - there's this wonderful online store that has a green version of everything I will need for all my gardening projects! It's called GreenGardenTools.com and it's THE place for Eco Friendly Power Tools & More.
TO BE CONTINUED..
I'll find out over time whether these strategies accomplish their purpose or not and I'll report everything in these pages.Do keep coming back!
Green Notes
I'm particularly happy that this project allowed me to live by one of my principles, that of using local resources as much as possible. I push that to the point of always checking the village hardware store first when I need something, even if it means paying a bit more.
The fact that the sand, gravel and stone are not only from my area, they are from my neighborhood, will continue to bring joy to my life every time I look at them, and make me forget how sometimes I've had to compromise on those principles because of money or practical issues beyond my control.
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