Friday, October 3, 2008

We have a basement

We're no longer just proud hole owners. We now have a basement in our hole. The crew came back today to strip the forms from the walls, apply waterproofing membrane and insulation, and backfill with a couple feet of gravel. I stopped by the site for a little while this morning, went to work, and here's what I saw when I returned in the afternoon:

The crew had finished stripping the forms and applying the insulation and waterproofing membrane. We're using a product called Platon from Certainteed to waterproof the basement. It's a dimpled sheet of thick plastic (24mils--about 4 times as thick as a contractor's trash bag) that prevents water from reaching the walls. Since it's dimpled, there's some air space behind the membrane that allows water vapor out of the cement and/or any water that finds its way behind the membrane to drain. It's fairly new here in the U.S., but they've been using something similar in Europe for several years. I think it's a much better choice than the tar paint or rubber membranes that are more common because it provides both waterproofing and drainage. Only time will tell.

The Platon membrane is covered with rigid foam insulation (1-inch, R5 insulation panels). I found out today that Wisconsin's Focus on Energy program will give me a rebate if I install 2-inch insulation panels (I found that out right after the 1-inch panels were installed, of course). I guess I'll have to head to the building supply store to get another inch of insulation before the full backfill next Thursday. Once I've applied 2 inches of foam, the basement will have R10 insulation outside the wall. When I finish the basement, I'll add another 2 inches of foam to the interior, giving me a total of R20 insulation on the basement walls (about the same as the first and second story walls). Since something like 30% of the heat lost in a house is lost through the basement, this should make a big difference in the heating bill.
Now back to the story. Shortly after I returned to the site, the conveyer showed up, followed by a dump truck with a load of gravel:

Code requires a foot of gravel covering the foundation perimeter drain (the form-a-drain forms serve as our perimeter drain). They used the conveyer to spread about two to three feet of gravel around the perimeter:

Once the backfilling was complete, I climbed in to the basement for the first time. It's great to see the house taking shape, but I certainly can't complain that it's taking a long time. We hadn't even broken ground 10 days ago, and now we have a basement. Here's a view of the southeast corner of the basement. It will someday house a bedroom and/or exercise room to the far left, and a rec room to the far right, a bathroom, and a furnace room:

Notice the windows. I'm going to try to make them as tall as possible to let in as much light as I can. Being on the south wall, the windows should make the basement reasonably bright. The northwest corner of the basement will serve as a theater room (we actually removed a window from earlier plans so it would work better as a theater):

And finally, the real reason we're building the house. My workshop:
The braces are a precaution to keep the wall from caving in when it's backfilled. They'll be removed after backfilling is complete (next Thursday), the steel is set (next Friday), the basement is capped with the first floor framing (probably a week from Thursday), and the workshop is capped with Spancrete panels (another week after that). Then the basement floor can be poured and the basement will be pretty much done. At least until I start finishing it.

That's about it for this week. We'll continue to collect rocks over the weekend, but for the next five or six days, we get to experience the excitement of waiting for cement to cure.

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