Once we filled in the big hole we’d had dug in the ground, I turned my attention to filling in the big hole we’d had cut in the basement wall. We want to turn that area of the basement into a legal fourth bedroom. For health and safety reasons a bedroom, especially one in a basement needs a window. There was a tiny ceiling level window the the space before. Once expanded, it now serves all those needs.
After a week and a half of protecting the house with just a well placed sheet of old faux wood paneling, I now have a functional window in place.
Before the window could go in, there was a bunch of concrete work to do – all the cut edges of the old concrete blocks needed to be filled in. I jammed old bits of insulation into the vertical holes to minimize the amount of mortar mix we’d need, then we mixed, poured and shaped. The trickiest bit was filling in the holes in the side walls – those needed some make shift “form work” of plywood to hold them – braced in place with cross braced 2x4s.
The base plate (treated) was set directly into the new mortar – a series of 3″ deck screws projecting from the bottom of the plate went into wet cement and then a mortar angled sill slopes down directly from that base.
From there we built up side panels and a top plate – also treated 2×6 – and connected snugly to the newly mortared side walls with concrete anchors. The top plate got two evenly spaced cripples to connect it to the house’s exciting mud sill. We used a construction window with a nailing fin attached on all four sides, then scored and snapped it off the bottom edge which sat flush on the base plate against a generous double bead of caulk. We also lined the side and top plates with caulk before installing the window and then sealed the edges again once it was in place.
I placed the window slightly lower on the wall than absolutely necessary so that it would be low enough to meet egress height requirements and to allow space above for a soffit to run continuously around the room above it. More on this later.
The final step was to close the gap over the window. I went with a PVC composite board for the window trim so that there could be no concern about rot or water intrusion. The outside is pretty much set for now (it needs some greenery come spring). Its time to turn my attention to insulating and furring out the interior of the basement bedroom.