Making window stools

[KLF]

Building a duplex for Habitat for Humanity, I'm one of the 2 guys that is doing all the construction oversight. Exterior walls are 2x6 with 1/2" OSB sheathing, but we also put 2" XPS foam on the outside, eventually will have vinyl siding. So, this makes for a very thick exterior wall, all the jamb extensions for the windows and doors will have to be ripped from 1x8's.

We are considering sheetrocking all the jambs for the windows, to save ripping all those expensive 1x8s, plus all that casing millwork for the trim. Simple look that is economical. But we still want a traditional wood stool cap and apron. Looking for advice on how to do these cheap and easy. This is not a high-end custom home with fancy woodwork, it's intended to be good quality affordable housing, with emphasis on energy efficiency. My current thinking is to rip 1x8's down so there is about 1-1/2" of overhang into the room, then put a simple rounded bullnose edge on it with a 1/2" radius bit.

We have a table saw and a good miter saw, looking for a router table setup now.

Suggestions?

[LCHIEN]

you'll want to use a 3/8" radius bit for a 1x8 (nominal 3/4" thick)...

to get a nice bullnose.

[pelligrini]

That'll work, you can also add some moulding underneath the overhanging lip. A simple cove can look pretty good. Even inverting some of your base trim.

A buddy of mine used some oak bullnose stair treads and a small oak crown moulding profile underneath. They turned out really nice.

[Mr__Bill]

I would leave them with a square edge just broken with sanding a bit. Add a piece of trim under and call it done. Remember to extend them beyond the opening the same distance they are out from the wall (assuming no trim around the window). Too far out and they start intruding into the room and getting in the way of things. I would keep it to about an inch. Don't forget to lay a bead of caulk on the edge and press it to the window, that is one place you don't want condensation to seep into. For a nice touch add some tile to the one in the kitchen.

I would also finish these before I installed them. It's quick and easy to stain and varnish/poly them and then stick them down with some liquid nails.

Bill
that's my opinion and I'll stick to it until I change my mind!

[KLF]

I was thinking of not creating a totally rounded bullnose, but more of just a rounded edge, which is why I was gonna go with a 1/2" radius bit. Keep in mind that this is not fine cabinetry work, most of our labor force is volunteers. I'm worried that if you don't setup the router table perfectly, and if the board is not fed exactly right in the table, a total rounded bullnose will make a mess that will need a lot of sanding to fix. We have to trimout 31 windows in all. If we just round the edge, it doesn't have to be perfect on alignment.

That's my thinking anyway...

[cgallery]

I like Bill's suggestions. A broken edge (compared to a radius) is going to look a little more contemporary, and doesn't require a router, just some sandpaper.

[eccentrictinkerer]

I just finished a basement remodel and used MDF for almost all the molding. I had HD rip the sheets into 8" strips, clamped the strips to a worktable, routed the profile on each edge, sanded then ripped in half.

I made over 500 feet of various molding at very reasonable price. The MDF looked great with 2 coats of primer and 2 coats of paint (sanded between coats). It went pretty fast, the owner was pleased and he saved money.

[KLF]

You know, that's actually not a bad idea. I have a really nice 8' straightedge, I bet with a fresh trim blade in my wormdrive saw I could rip the strips we'd need. Hmmm...

[Bill in Buena Park]

KLF,
1/2in radius roundover seems too large; I'd recommend 1/4in as the "edge breaker". If your crew isn't familiar with how to handle MDF or seal MDF edges, I'd stick with wood.

[Shep]

KLF,
1/2in radius roundover seems too large; I'd recommend 1/4in as the "edge breaker". If your crew isn't familiar with how to handle MDF or seal MDF edges, I'd stick with wood.

+1 on 1/4 inch.

This will also be a lot easier to make with a router table. There is not as much material to remove and this will result in a cleaner cut line.

[billwmeyer]

I have done my house by just breaking the edge with sandpaper. It is quick, easy, and looks good.

Bill

[JimD]

You'll want to drywall the three sides first, of course. It would be too hard to fit it to the stool otherwise.

Cutting them to fit in the opening will be a challenge. Highly likely the drywall sides will not be be at right angles to the wall surface. Caulk can probably solve it, however. It might be worth making one to fit tightly and then having volunteers nail it to other pieces and use a flush trim bit to cut the others. You'd still have to do a little hand work in the corners but they should fit.

Jim

[cgallery]

You'll want to drywall the three sides first, of course.

Interesting that you say that.

If it were me, I'd install the stool first.

Then I'd drywall the top.

Then I'd do both sides. I'd probably use a very thin metal j-bead on the bottom edges of the sides.

Why would you do the drywall first?

[JimD]

If you J-bead it it would probably be OK but an unprotected edge of the drywall would be much too fragile. If you run the drywall behind the stool you could skip the J-bead. My admittedly limited experience with drywall for Habitat indicates it will have pretty generous clearances. A big gap could be filled with drywall compoud but then you have something fragile again. You also have the coner to consider. If you do the corner later you have to finish it up against the stool which will have drywall compound against the stool again which would be fragile and might get wet from condensation on the window.

Doing the stool first would make fitting the stool easier. Then only the front edge that goes against the window and the part that goes against the wall have to fit tight. The sides could be crude because the drywall would cover. And you would have right angles or closer to them to work with. With edge bead on the drywall you won't have right angles. So there are advantages both ways.

If you do the stool first, I would use setting compound on the drywall where it meets the stool. There could be condensation and drying compound stays water solubile. Setting compound is more water resistant. Setting compound is sold dry. I also like it in bathrooms for similar reasons.

Jim

[KLF]

Thanks for the input.

This is a first for me in this position, but there are lots of firsts for us on this job too. Dow is very generous to donate all the 2" XPS that we want, so we did the entire outside of the house with it. But, that makes an 8" exterior wall and manufacturers are not up to speed with this yet with pre-packaged jambs and such. So, we're winging it here and there, trying to be energy focused but it also needs to be very low cost.

We had a guy on site this Saturday that does a lot of custom trim work, he suggested fiberglass-based drywall for the window jams, and setting mud. I guess we'll give it a try, none of us has any experience with this type of thing, and we can't leave an ugly mess for the new owners. I think instead of MDF for the stools, we will use poplar, as I'm worried about any moisture. All it would take would be a few scratches in the paint of the stool, then leave the window open in a rainstorm, and the MDF will swell up and ruin.

I hear ya on the tough fitting. I think we will do the drywall first, then install the stools. Caulk will fix a lot of errors, fortunately we are painting everything.