Hi all,
I will shortly be replacing some windows (full tear out, “new construction” windows to be put in). The new ones are aluminum clad wood with a nailing flange.
I want the exterior trim to be traditional with a “sill” and wide side and top trim. I have seen in a couple of posts the idea of making a “false sill” for this type of installation but can’t find any instructions/diagrams for how to make one. Can anyone point to some references for me?
Thanks!
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Replies
I can describe how I do it.
I take some 5/4 stock usually, unless I need to match another thickness.
Then I rip the first edge 13°, set the fence to make another rip so the piece is about 2".
Then I lower the blade so I can make a drip lip in the bottom edge about 1/4" in from the leading edge with another pass.
Then flip it around to take a shave hair off where it fits up under the window projection.
We attach with trimhead screws and caulk behind.
I can sketch that in a few minutes here
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Drawing I found I had already from a previous similar discussion.
It shows a dado lock for siding also that is not always needed.
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Where do your trim screws go with such a wide sill?
Our sills are narrower, as you said in the first post, 2" or less. We normally use 3" deck screws going in from the outside face, countersunk and filled with bondo. If we have no dado for the siding, we also screw up into the side casings. If there is a dado, this does not easily work.
we kreg jig ours to the side legs from the back side
I can get trimhead screws up to about 5"
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That would do it.
What kind of trim is that in blue under the sill piece? Is it needed for strength, like the trim under the stool on the interior?Thanks for the info, by the way...I did see that diagram but wasn't sure how to make it!
That is an apron piece, and goes on after siding.
How it is detailed depends on the style of house or whatever else I am trying to match.It does help support the sill, but is not necessary
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Thanks, Piffin --I'm going to be putting a window in the bathroom sometime soon, that drawing is a lot of help.
Leon
1) I was poking around and found on Azek's site what they call "historic sill" moulding...which looks very similar to what folks here are making custom. Other than cost savings (I haven't priced Azek's but assume it's not cheap), are there reasons for making custom sills? I think their premade would look better quality than what I can make.
2) I have tried searching for this but couldn't find a specific answer; please refer me to a post if one's already been done...but I would like to use a traditional drip cap (sloped piece of wood...well, I'd use Azek but you get the idea) since my other windows have this, but I can't find specific instructions on how to make sure it's flashed/weatherproofed properly.
Thanks for all the advice thus far!
I found this if you are bending aluminum for the sill etc..
http://www.expertvillage.com/video/75137_add-windows-house-bending-flashing.htm"If all women are crazy...I married their Queen!!!!"
Mike Smith show making one out of trex.
But the advance search would not find it.
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Often I'll use the existing sill on tearouts like you describe.
Just rip off the portion that goes inside the wall and nail it, or use pocket screws to fix it in place for show.
Not sure you have something good to work with tho.
i have trouble copying links on my Mac
but the methods we use for false sill are well documented in
## RFH Ranch ### starting with about post #160
If you can't link can you give me the number of the post? I tried searching for RFH Ranch but got no results. Thanks!
here's apic from ##RFH Ranch ##
this a trex sill ripped from old style trex ( 2 sills from one 5/4 x 6 trex )
we also make it from 2x4 trex
View Image
you can see the sill is fastened thru the face with 3" deck screws.... then the holes are filled with bondo
where piffen referred to 13 deg slope, we use 10 degree
BTW the casing is 5/4 x 4 Miratech
Edited 5/27/2008 9:49 pm ET by MikeSmith
I finally found the old post you were referring to. Thanks for the detailed pics previously.
Another question: how did you figure the size of the rabbet? I'm assuming from the pics that the depth should be enough to give a little gap between the siding and the sill piece. Is the height supposed to be the same as the nailing fin? Or a little larger or smaller?
Thanks!
generally we use a 3/4 by 1/2 rabbet
the 3/4 allows for a full shingle butt to tuck in the 1/2" depth
most sidings are full thickness right under the sill
that pic i used didn't show the one more layer of fibercement that was later installed
si we used the full rabbetMike Smith Rhode Island : Design / Build / Repair / Restore
I do something similar to Piffin's, but with 2x4 Cedar, ripped 13 degrees also, with a notch so that the sill sits up tight to the window in the middle and the ends keep the bevel. This way I can put a piece of 5/4 beveled the same degree on the bottom, which I like as far as shedding water.I generally rip the sill around 2-3/4" to the long side of the bevel. Like to hang the end of the sill around 3/4" past the outside of the 5/4 cause....It looks right to me. I also rabbet about the thickness of the blade out of the back of the sides and top pieces to make up for the thickness of the nailing flange.Usually attach mine with ceramic coated decking screws through the bottom into the beefy part of the windows sill, being careful to keep from poking through. This may not be practical with the al. clad windows you're using tho, so attach whatever you use with whatever makes sense, in regards to water infiltration, etc.Obviously, the usual vycor/paper/head flashing details complete the picture. ( which I would post if I weren't so inept with this computer thingy...)
Bing
Edited 5/27/2008 10:07 pm ET by Bing187
Unless you absoulutely have to have the sills I'd forgo them. I'm replaceing window trim on my home now and takeing out the ones I HAD to have l5 yrs. ago. Dirt collectors and maintance issues. If you do go for them make the slope 15 degrees, there's a stop on the saw for it, and it sheds water much better. Don't forget the drip lip either, I face screwed and pluged the holes.
Can't you get an aluminum sill from the window manufacturer? I Know that Marvin makes them. They are color matched to the clad on the unit.
"It is what it is."
I use 5/4 x 6 cedar or trex decking...already has two finished edges. Can be ripped right in half with the blade tilted about 10* for two milled sills in one pass (two passes for a shallower sill.
I use the same stock for both sill and drip cap.
Given your description, can you get Marvin's 'simulated thick sill' (a standard item in an all-wood window) in clad? If so you can save yourself a lot of labor by ordering Marvins with casing pre-applied.
Jeff
Here's one of mine that I did 7-8 years ago when I replaced all of my aluminum framed single glazed windows with double glazed, low-e windows.
I used KD 2x4's and ripped them down just enough to lose the rounded edges. The sides are attached to the top with pocket screws. The bottom board was ripped at ~12* and I ran a saw kerf on it's bottom for a rain drip.
I ran a 1/4" round over router bit around the inside and outside of the top and sides and over the ends and front edge of the bottom board.
The bottom was attached to the sides with 5" deck screws and the whole thing got a good coat of primer before it was installed using 3" deck screws.
I did all eleven of my windows and the sliding patio door. I also did variations on them for about six customers.
They're relatively easy and inexpensive to make, and I think that they add a nice "look". They also make it very easy to remove a window if it's necessary - which I had to do when one of a customers windows was broken.
Azek has a product-sill material-
I build an azek frame (last one I Kreg'd together) of 5/4x4 or 6 (or put 4" on sides and bottom and 6" on top) I then just cut the AZEK sill so it extends either to or just past the 5/4x on the bottom and return it on itself. Not architecturally accurate but close and looks good.