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Framing windows in 16" walls

Posted: Sun Jun 29, 2008 8:40 am
by mtngun
I tried several types of window frames before settling on this method. It is very slow but the result is rugged and handsome, and requires little additional trim.

First, a 4"+ by 8"+ slab is cut from a log with a chainsaw. I cut them freehand, but a chainsaw mill would work better.

Since my freehand cuts are pretty rough, I plane the slabs, and use a table saw to trim the edges (a jointer would work better, but it's still on my wish list). A dado blade is used to cut slots to accept a spline. Image

Then 2 slabs are glued together to make a true 4" x 16". Splines are simply slices of OSB. Image

The 4 x 16's are sanded..... Image

Dado slots are cut on what will become the exterior side of the window frame. The dado slots will allow mortar to key into the window frame.Image

Sharp corners have been rounded over with a router. Image

This is enough slabs for 3 windows. Image

Re: Framing windows in 16" walls

Posted: Sun Jun 29, 2008 9:17 am
by mtngun
Here's a pic showing the ledges cut in what will be the bottom piece of the frame. The ledges on the side accept the side slabs. I started out using a router to cut the ledges, but later switched to a table saw. Image


Testing how the pieces fit together. Eventually, they'll be attached with construction adhesive and long lag screws. Each slab weighs 50 - 100 pounds, depending on the type of wood, so it is not feasible to assemble the frame on the ground. Image

So.... the bottom piece is laid in a bed of mortar. Next day, the side and top pieces are attached. Temporary braces and clamps are used to hold it square until the walls are built around the frame. In addition to the dado grooves, I install drywall screws around the outer edges of the frame, leaving half the screw sticking out, to give the mortar a good grip on the frame. Image

After the cordwood was complete, the frames received a 2nd coat of stain, and then the windows were installed. They still need a small piece of trim around the edge of the window, but otherwise ther frames are done. Image