The Video:
My time-lapse camera is pretty basic and has a manual focus. I had it set to 8ft instead of ∞. Easy mistake ;^). But here is the slightly out of focus video anyway.
The Story:
I was not able to be on site when the crew setup the formwork and rebar for the garage slab. When I did see it, I realized it would need to be redone. Engineering had been done by 2 different engineers… The first was the engineer that I had hired to do the entire project. He specified rebar every 24 inches across the slab. The engineer from SteelMaster specified 6×6 WWR (welded wire reinforcement). I decided to do both. The guys who assembled the footings were only looking at one of the drawings, so they just put down the WWR. In addition to adding rebar, I wanted to add a vapor barrier, rigid insulation and radiant floor pex also…
First, I waited for the plumbers to come and do their work roughing in the garage bathroom. While they were working, I removed the large sheets of welded wire reinforcing and bent 40 peices of repar to put into place. After the plumbers were done their work, I tried laying it all out myself. However, I soon realized that positioning 16×8 ft sheets of welded wire is really a two man job. I decided to phone a friend. Aaron was willing to give me a hand early Saturday morning.
We started by excavating away a couple inches of sand in the areas where we planned to place the rigid insulation. At nearly 27$ per sheet, I didn’t want to insulate the whole slab, but I did want warmer feet in the bathroom and workshop areas.
We cut and laid the insulation carefully around the plumbing for the bathroom. And then in an “L” shape where my workbench would be…
Then we unrolled a 20ft wide sheet of 6mil poly to use as a vapor barrier under the slab and under the footing all the way around. Here, we are lifting the rebar in the footing to get the plastic underneath it.
The poly sheet was 20’ wide, so we had to do this in two overlapping pieces… Which Aaron taped together.
Initially, we had rebar chairs down the middle, but they were too tall so we had to remove them later.
I measured out and marked the 24 inch intervals for the rebar using surveyors paint.
Then we laid the rebar, using small bits of insulation as spacers. We put the 6×6 WWR on top of that.
Lastly, I brought out some pex pipe for future radiant floor heating… The pex was much longer than I needed for the bathroom, so I made a last minute decision to swing a loop out past my workbench… I secured it to the Welded Wire Reinforcement ever few feet.
The last thing that needed fixing was the wooden board that had been put in place as a keyway for the quonset hut. It had been installed too shallow and had been put in the wrong place (even though I had clearly marked where it should go). We decided to let the experts fix that mistake on the day of the pour.
The Mistakes
- Perhaps I should have excavated a bit more before placing the rigid insulation. It seemed OK at the time, but after adding spacers, rebar, WWR and radiant tubing, I wished I had it an inch deeper.
- I may regret adding the pex loop thru the shop… It may end up making it difficult for me to heat that bathroom adequately without also wasting heat in the shop.
- I only tied off the pex every few feet. But later, when we added the concrete, many sections floated to the surface. The crew pushed it back down again, but then later they didn’t want to cross cut the back half of the shop. Of course, cracks formed along where the PEX tube was too close to the surface.
After digging the trench and laying the septic pipe, drain tile and earth tubes, it was time to backfill the trench. We started at the top by the house, but I didn’t record the first couple hours for some reason, but I caught enough of the rest to put this video together.
The Video
The Story
We placed the earth tubes by staking them into the side of the slope. This saved us from killing ourselves manually back-filling the trench on what turned out to be the hottest day of the year. However, it did slow down the back filling process. Instead of just pushing the dirt back into the hole, we had to carefully (and manually) backfill around the earth tubes so they would keep the right position and slope… I guess this added another couple hours of backhoe time to the true cost of the earth tubes.
I was actually surprised how the excavator attacked the problem. I guess I naively thought he would bring the dirt in from the side where the dirt had been placed… Instead, he started from the other side and dug his way down. He dug undisturbed dirt and put it in the hole under and around my earth tubes. Once the tubes were covered enough to protect them from the excavator and there was a slope for him to climb down into the trench (in the video, you can see him slip a little), the excavator was able to reach up and pull the sand from the far side, down into the trench. From there he was able to quickly move up and down the length of the trench pulling in the dirt.
Eventually, when the trench was almost full, he was able to climb out the far side and reach some of the other dirt.
At some point, Dick parked the excavator and got into the bulldozer to level off and “reshape” the hill.
At this point, the Septic field is not yet complete, so there will still be some more earth moving before the septic system is complete.
My Pink Skirt
Marty and Dick knew I wanted a flat area 4 feet up the wall to put an insulation skirt in, so they flattened and tamped the ground in that area for me.
Meanwhile, I had been doing my own work for my employer in the trailer, but when they guys took their regular lunch break at noon, I started my 1 hour shift.
The idea is trap a bubble of heat around the house with an insulation skirt or umbrella. This idea was popularized by John Hait who calls it “PAHS” or Passive Annual Heat Storage, but the idea had been fully researched by the University of Wisconsin several years earlier. You can read more about it here.
The umbrella is really supposed to be several layers of insulation with layers of plastic between. I only put in one layer of 2 inch Rigid insulation (Foamular 250) and ran it out about 16 ft (2 sheets) from the house. Since this is really more of an insulating skirt beyond the basement rather than an umbrella over my home, I didn’t feel the need to go the full 6 inches thick that I plan to over the rest of the house. Similarly, I didn’t feel the need to put several layers of 6 mil plastic in this location. Instead I just went with one layer of pretty think painters plastic. The point of the plastic is just to reduce the amount of water that can go thru this area and steal away the stored heat with its high specific heat capacity. I sloped it all way from the house and covered it over.
I will eventually overlap this skirt with the larger insulating umbrella. Our backyard patio will eventually go over this area.
Before we can back-fill against the basement, we needed to clear the area, waterproof and put in the drain tile… We also needed things like radon tubes and floor drains to exit the building.
My wife, Sherri, had to help a lot this week… And as she puts it, “It wasn’t princess work!” I did try to hire some people, especially when I realized I would have to carry down and place the 4 yards of pea stone by bucket, but it didn’t work out and we were on our own.
The video is here…
Stripping
I started with stripping the bracing away. In most cases the wood was perfectly good with only a few screw holes. I will get to use it all again on the second floor. Actually, the site has only generated a couple bags of garbage and a box for recycling all summer, and that was mostly lunch trash dropped by the contractors working on the site.
I left the insulation on the side of the window well. It was meant to be forming, but with an earth sheltered umbrella, it helps to insulate the earth where ever you can.
Waterproofing
We bought a power sprayer from home Depot (Graco Magnum X7), which worked pretty well. We justified the purchase by reminding ourselves how much work it had been to paint the ceilings in our current house when we moved in. This sprayer will come in handy when we do one last paint before we put our existing house on the market next spring. As for the current task of spraying on the waterproofing, we saved a lot of time (and got better coverage) by not trying to roll the water proofing over that rough surface. With only one sprayer, it was a one person job and Sherri took care of it.
As for the water proofing its self, we used ProteShield Elastomeric Waterproofing Sealer. We actually applied it about 50% thicker than the directions specified. The instructions said it would dry clear, but we were surprised that it appeared to “disappear” after just a few minutes (and faster on smoother sections of the wall). It was like it wasn’t even there.
When we got the waterproofing inspected later, the building inspector was concerned about it. He gave us a “partial” pass, and told us we could proceed at our own risk, but if the waterproofing doesn’t qualify, we will need to dig it up and do it over again. We proceeded with the back-filling on faith in Home Depot and (later that evening) sent him this technical data sheet, which mentions that it is for above and below grade waterproofing of basements and foundations. It even says to give it 48 hours to cure before back-filling, we gave it double that. However, the inspector says it is missing a mention of some specific government tests that would qualify the waterproofing for use as below grade waterproofing. The inspector is going to try and contact the company to see if they have this documentation, and if not, he is going to insist that we redo it.
Drain tile
I suppose drain tile used to be made of ceramic tiles curved into tubes and then fired. In hispanic areas, I have seen them use the same tiles they use on the roofs. These were placed end to end to help carry water away from foundations. Now days, they are made of HDPE plastic that lasts forever. Ours was also covered in a nylon sock to keep the sand from clogging it.
Actually, our site doesn’t even really need drain tile. The sand just lets the water fall thru it, but the building code says we need it and that we need it to be covered in pea stone (an extra cost/hassle that shouldn’t be necessary for such a sandy site).
Another neighbor in the area told me that he put in the drain tile around his house to satisfy the inspection, but then didn’t actually run it to anywhere, since that part is not actually inspected.
I agree that these drains will probably never carry water, but I decided they should at least do something. I am going to use them as earth tubes to carry fresh air into the house. Sherri doesn’t like the idea of carrying fresh air thru corrugated pipes because water can sit in them and cause problems (mold, humidity)… But I also know of many success stories. I wanted to try it out and I can always seal them up if it doesn’t work out.
The first day that we laid the drain tile, the battery died in the camera, so you don’t see how many hours it took me to get it all sloping just right.
The big hassle on the second day (Saturday) was carrying all that pea stone down into the “pit”, bucket by bucket. We didn’t make our Saturday night deadline. The inspector is only available for a few slots each week, so if we missed Monday for the pre-backfill inspection, we would need to put off the back-filling and schedule the inspector for Wednesday…
That was the the day my sister was coming into town… We would need to come back and finish up then.
Insulation
You can’t see it in the video because Nick and I were working on the other side of the basement. We initially hoped that the waterproofing would be sticky enough to “glue” it, but it was not sticky at all. So we waited for the waterproofing to dry (2 hours cure time), and then tried to glue 2 inch thick Foamular 250 to the walls using “Liquid Nails“… That didn’t work out at all because we couldn’t keep the stiff foam pressed against the curved wall long enough for the liquid nails to dry. We decided to add the insulation as we back-filled… The dirt will hold it in place very well.
