It is bitterly cold out. We had hoped to be further along in the construction before winter truly hit. Disappointingly we had a month delay due to our foundation walls. Superior Walls, a pre-cast concrete wall supplier, originally estimated a 3-4 week production lead time but ended up scheduling a seven week lead time. This gave us an end of December delivery. We were able to use the extra time to finish up site work and continue discussions about various details of the project but it did feel like wasted time. Especially with winter creeping up.
The process of installing pre-cast concrete walls was interesting and I’m glad I got to watch. Ahead of time my builder dug down below where the walls would be placed and filled to the appropriate thickness with gravel. Then the surveyors placed stakes at all 10 corners (imagine three rectangular boxes with two sharing a back wall) with the assistance of GPS. After the survey was complete the Superior Walls crew placed metal rods every several feet horizontally on the gravel where the walls would go. They tapped down the rods to the final grade then swept the gravel in between to match. The metal rods were removed prior to installation.
Then the crane picked up each wall (some weighing over 5000 pounds) and carefully brought it over. The crew positioned each section and used sealant to join them. They tightened metal bolts between them as well. Each piece went together smoothly over about a day and a half. My builders were happy with the walls and installation.
Superior Walls markets themselves as a very watertight product with a high PSI. Since they can pour their concrete in a controlled environment on a flat surface they can achieve 5000 psi. The weakest parts of the system are the edges where two pieces are joined. Supposedly the sealant and bolts create a tight connection. We are still going to water proof the north side as extra insurance. It’s one of those relatively cheap things to do now to prevent a potential major headache later. They also insist that their R value of the Xi Plus walls is 20 on average, but this includes a low value of 3 at the studs. It’s because concrete is a terrible insulator and at the stud it’s almost entirely concrete. Makes it hard to improve the R-value at that location since it’s the thickest part.
But on the whole it should be a very well insulated wall. It’s great that it comes with the studs premade with wiring conduit. We hope to finish our basement at the end of the project and this puts it in DIY territory.
It’s exciting to see our house really get underway. The next steps are going to be very cold for our builders who will be framing next week. But the next couple months should be amazing with a ton of changes happening every week.