Finally getting around to putting extension jambs on windows in my house. The windows are Anderson 400 series set in SIP walls which are 7″ thick. I bought factory ex. jambs which are 7-1/8″ and test fit a couple – they fit fine, maybe a bit of shaving with a block plane and they will work great.
The problem lies with the means to attach the extension jambs to the windows themselves. I have seen “jamb screws” basically a long trim-head screw, in McFeeleys catalog, but I have no way of getting a screw and bit in behind the jamb to attach these things. I am stumped. I have though of just running a bead of glue in the groove on the window, just gluing them in, but I have no good way of clamping them.
Anybody have a solution for me? Thanks.
Replies
Use shims on the sides and nail through, just the way you would hang a door.
Beat it to fit / Paint it to match
I must be missing something. Wouldn't you screw through the front edge of the extension and into the original jam?
Or follow these instructions:
http://www.hammerzone.com/archives/finishcarp/casing/jambextn/window/andrsn.html
Thanks, that's a great step-by-step.
Problem is that some of the jamb extensions are about 5" wide and that method doesn't work awfully well. Need to find another solution.
They get screwed right through the front face of the extensions, and when casing with a 3/16" reveal, the fastener holes are covered.
Let's see. You said your SIP walls are 7" thick, so I am taking that to mean your total thickness, outside "rough" face to inside finish, is the 7. That is 1/2" thicker than a conventional wall framed with 2x6s, sheathed with 1/2", finished with 1/2" gyprock on the inside. That would mean that your extensions are about 2.5 inches in depth when planed to fit.
Right?
That being the case, you need McFeeley to sell you their jamb extension trimhead screws at a length of 3.5 inch minimum. They sell them at 3.5 and 4.5 inch lengths. Be sure to buy their long drill bit, too.
Here ya go. View Image
Good luck.
Edited 8/19/2006 2:21 pm ET by Gene_Davis
Nope, but wishful thinking. You're right about the wall thickness - it's OSB both sides of 5-1/2" thick EPS foam, with a layer of 1/2" drywall on the inside.
However, Anderson shipped these with no jambs. The actual width of the extensions varies from about 2-1/2" on the doublehungs to 5"+ on the awning windows I have. And I have 14 awnings. That's where the problem lies. Every one is like that. I can use the screws for the narrow extensions, but not for the wide ones.
Not keen on the shims and finish nails, I'd prefer another plan. Don't want to fill nail holes as the jambs and extensions will be a clear natural finish. I'd rather see plugged screw holes.
Ahh! Good old Andersen. Gotta love 'em, and many folks do.
Just about any other window company would have done windows for you with factory-applied extensions, but not those guys.
You weren't aware of this at planning and buying time?
Looks as if you'll be blocking and shimming, then nailing them in, going through the faces and into the surround subframes. Too bad.
Drill deep "countersink" holes in the thicker ones and use the screws, plus glue. A 2.5" deep countersink will let you use 3.5" screws on the 5" thickness.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Painter's stir sticks (i.e. the thin wooden little paddle they give you with gals of paint - usually free for the taking); double-back carpet tape (make sure you run it right out to the extensions, or the height will change); slow "cy" glue or regular with a retarder; have pinner handy to tack up the odd one that won't stick; extensions get made; sticks go on the extensions first, beard of adhesive on the window side; position and hold for 60 seconds.
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Phill Giles<!----><!---->
The Unionville Woodwright<!----><!---->
Edited 8/20/2006 12:15 am ET by PhillGiles
How hard would it be to get the windows back out at this point?I was wondering if you could take 'em out and use a pocket hole jig to attach the extension before re-installing.If taking them out isn't an option, the pocket hole jig COULD be used on the inside. They make wood plugs that the holes could be filled with.
Can't get the windows back out - house is all trimmed and sided on the outside.
I thought of pocket screws, but the plugs aren't as neat looking as I'd like.
Some good ideas in this thread, though.
We just did a house full of these - 13" thick walls, 400 series windows, cedar 1x12's extension jambs. We didn't buy jambs, and we didn't attach them to the windows, only the sides.
I am assuming with the sips you have 2x material that your windows are attached to. Then place your sills as normal, then cut your extention jambs to length (leave the sides 1" long)and assemble w/ your 15 gauge nailer (I use glue too) the top piece between the sides. If you want you can rabbet the top into the sides.
Slide into place, shim and nail.
In your case, you could run your bead of glue in the groove, slide everything in, and nail to the sub frame. Either way, preassembling will keep your corners tight.
Holy crap, and I thought I had problems. 13" thick walls? Was it a missile silo?
Thanks for the tip, though. I never considered simply not attaching the jambs to the windows. The problem is still the nail holes, I guess I can come up with a solution to that (mix shellac and fine sawdust as putty).
ICF walls.
Treat every person you meet like you will know them the rest of your life - you just might!
Yeah, of course. Even more stupid of me since my basement walls are ICF's and I have to trim out three windows in it. I just didn't think since the basement finishing is much further down the road.
Why can't you just run a bead of glue, open the windows, and use a 12" bar clamp to hold the extension jambs tight to the window jamb?
Jon Blakemore
RappahannockINC.com Fredericksburg, VA
I would prebuild as many of the jambs as I needed, glue and screws.
A day later I would cut biscuits into the jambs and the extension box. Glue them together and clamp, once clamped into place shim and nail to the framing.
Pull the clamps before you go to bed.
I'm a fool to do your dirty work.
Normal method like the others said is to shim and face-nail.
But, you might try this glue http://www.amazon.com/gp/product/B00008US7G/qid=1129914272/sr=11-1/ref=sr_11_1/002-0165181-3688840?n=228013
I use it all the time for projects where I need a quick setting time. You could run a bead (or even just a few drops) on the edge of the extension jamb, spray some activator on the window, hold in place for 10 seconds and move on to the next one.
It's amazing glue.
Mike Maines
I have done this dozens of times. Just cut all of your extension jambs to size and assemble them into a complete frame. ( They will look a lot better at the corners using this method anyway). Then just glue ( in the groove) & clamp the jambs into the openings. You can hold them with padded bar type clamps where possible or make some little blocks with one hole in them and run a screw into the 2X around the edge of the window with the other end pushing the jamb firmly into place. Let the glue dry for an hour or so and you're all set. The trim around the window will cover the screw hole in the drywall. This is easy to do with Andersen windows because of the groove the jambs fit into.
McFeely's screws work great with smaller width jambs.
If you assemble the boxes first (as you should), you will have a nice solid structure to work with.
One thing that I do is rabbet my top and bottom into the legs 3/8ths or so. The depth isn't crucial, but I can't tell you how many people I've seen that just want to do butt joints with no rabbet. Easiest way is to use a router. But you don't need to get fancy, even using a circular saw will give a decent fit if you are careful.
Don K.
EJG Homes Renovations - New Construction - Rentals
That's great advice Don. I cut them all to size and then dado them. That's the difference between a professional job and a typical job!!