Basement Floor Prep – Stone and Insulation

Basement Digout

Mario, our concrete mason, came out on Saturday and put down the stone that makes up the bottom layer of our new basement floor. I had hoped that he would also install the layer of rigid foam insulation that makes up the next layer, but apparently that’s not in his menu of services, so I was on the hook to do it myself. More than that, he wanted to come back on Monday to put down the plastic and the mesh, so I needed to get it all installed on Sunday. My friend Dean and his dad, Hector, once again offered to help.

Insulation delivery
Insulation delivery

The first challenge was getting the insulation. We’re using 4′ x 8′ panels of 2″ thick XPS (extruded polystyrene) foam, which are commonly sold in different densities. The higher density foam is better for under concrete because it doesn’t compress as much. Unfortunately it’s not stocked in as many places and I was buying 30 panels. I placed an order Saturday morning at a Home Depot that had “99+” in stock. By late Saturday afternoon the order still wasn’t ready, so I called them. After being on hold for 15 minutes I was told they “couldn’t find it” and apparently had zero in stock. There was only one other Home Depot near me that had enough in stock, so I switched the order to them. They had it ready by 6:30. Unfortunately they didn’t have a truck available, so I wound up renting a truck from a Menards that was nearby (they didn’t carry the foam). I went to Menards and got the truck, drove to Home Depot, manhandled the five-foot-tall stack of foam onto the truck, drove the truck home and dropped off the foam in the back yard, drove back to Menards to return the truck, and finally drove back home.

Sunday morning came earlier than expected (due to the Daylight Savings time change) and Dean and Hector showed up. We started at the front of the basement and worked toward the back, using the hand tamper and a rake to even out the stone base in places. The concrete curb around the footing and the column footings have rough edges that we couldn’t get the foam completely flush with, but we worked around them as well as we could. The bigger challenge was the plumbing. Because the plumbing in the basement drains to an ejector pit, the pipes aren’t particularly deep. That meant in addition to cutting holes for the pipes themselves, we had to allow for horizontal pipes and fittings as well, not to mention the sump basin and ejector pit. Overall the process went smoothly and after several hours we had everything installed. I did some foam sculpting to cover up the bathroom plumbing group and I’m pretty pleased with the end result. We were frugal enough with the foam panels that I have seven left over to return. Since they cost me $32.50 each, I’m happy about that.

Insulation installed
Insulation installed

Mario is back today to put down the plastic and mesh, and then Lester (our radiant contractor) will be out next week to attach the PEX tubing. Mario should be able to pour shortly thereafter. We’re still working on the painting and prep for the front window and back door. I hope to have posts about those projects shortly. A big thanks go out to Dean and Hector for all their help!

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