# Installing Window Directly to Studs



## Colbyt (Jan 27, 2014)

Does it have house wrap or felt?

I am not a pro window guy. If it were me, I would apply the adhesive flashing under the nail flange and over it use a U shape |___| at the bottom, do both sides and reverse the U at the top. On top of the flange cover completely always shedding water to the bottom. bottom first, sides and top.


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## Windows on Wash (Aug 30, 2011)

T1-11 homes are an interesting set up. 

Peal and stick is basically worthless here. If you are going to be replacing more windows down the road, I suggest you look at altering your trim approach and plan on using some sort of 1x4 and make your flashing details with that in mind. 

Do you have access to a metal brake?


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## leclairk (Aug 1, 2015)

The house has no house wrap right now but I plan on putting some up when I install the new T1-11. I don't have access to a metal break. I do plan to install new trim around the entire house. I thought about incorporating the trim with some metal flashing but I'm not sure how that would help. I think the best I can do is find a piece of Z flashing with a 3 or 4" backside to go up the studs. I might wrap the 2 vertical studs with some adhesive flashing wrapping the flange to the stud, although I'm not really sure if that would help. Thoughts?


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## Gary in WA (Mar 11, 2009)

5/8" T1-11 is a structural siding, does not require sheathing or wind bracing. I installed a lot of it for about 5 years in the 70's. I would roll out the required WRB (building paper), add the windows, add the siding. Use some sticky on the framing near the window, add as much as possible of tar paper, caulk perimeter (except bottom) of window flange on paper, then add the window, then a piece of drip flashing (z-metal) but don't nail it. Crimp the ends closed to dam; http://joneakes.com/jons-fixit-database/2062 Install the new siding, starting from the under-lap side first.

You may find; the new window flange is deeper toward the house (usually 1/4") to make up for the double-pane/newer design. This may required cutting (ripping) that much material from the outer edge of the window stool/jambs/head. OR it may have painted plywood jambs/head and a wood sill/apron, which may also require ripping (very hard to patch for adjoining texture). Done a few of each, lol, let us know if you need more info. This may help; http://www.civil.uwaterloo.ca/BEG/Downloads/Can_arch_Bldg_Paper-2001.PDF

http://buildingscience.com/document...-start/view?topic=doctypes/published-articles

Download at bottom; http://buildingscience.com/document...rame-wall/view?topic=/doctypes/researchreport

Do you know how to install flashing over the window/trim?

Gary


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## leclairk (Aug 1, 2015)

Thanks for all the tips guys, I think I know my plan. Tell me if I'm missing something. I'm going to install a vapor barrier, rolling a section up to lay back down over the top of the window. Install plastic corners on the sill (http://www.homedepot.com/p/SureSill...dow-Box-of-100-corners-SC-3-50C-COR/202074058
Lay down some 6" adhesive flashing over the sill and the corners. Caulk the window(except for the bottom) and install the window. Wrap the sides and top of the window with 4" adhesive, wrapping the window flange to the studs. Next install the drip cape with a bead of caulking along the top and lay the vapor barrier back down over the drip cap and tape down it down. Next, install the siding and caulk between the 1X4 trim and the window. I think that's the best I can do.
And no, I don't have any experience installing flashing over window trim, that was one of my next questions. What's the best way to prevent water from running down the channels of the T1-11 behind the trim? Thanks guys.


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## Gary in WA (Mar 11, 2009)

Careful as to when you add the black paper; read BOTH pages; http://www.diychatroom.com/f104/window-trim-question-117375/

I would add the caulk under the head flash after the siding is on when the top area around window is loose enough to adjust the flashing. The space above window should be 1/2" to allow for flashing bent down more than 90*- and still allow 3/8" gap from T1 to flash resting on window for drip edge. I have even cut the head hole at a slight angle (5*) for added drip before, though not necessary. After cutting window hole, before placing to nail siding, rub some caulk on cut edges (window hole) to protect edge-grain and help later caulking to bond better. I use backer rod and caulk for better looking "hourglass" shaped bead; pp.35;https://books.google.com/books?id=X...Q6AEwBzgK#v=onepage&q=capillary break&f=false

Trim, IMO, flash 2 times, one above/below it if window was "c" on pp. 18/21 here;http://www.mtcc1170.com/images/BCRainScreen.pdf ignore the rainscreen, note all the pics are good in link.

Gary


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## leclairk (Aug 1, 2015)

Thanks for all the tips, this is great. I would have butted the trim up to the window as tight as possible. The only problem I see with installing the flashing on the head piece is at the corners. If I cut the T1-11 to leave a 1/2" gap above the window, won't there be large gaps where the window corners, flashing, and T1-11 meet? Does that make sense? Should I just use extra caulking to prevent water from getting in behind the T1-11?


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## Gary in WA (Mar 11, 2009)

I add a corner bead as you said. Be sure the bend the metal flash for end dam, not cut the bottom corner that would allow water ingress. Not that noticeable after painting it house/trim color. 3/8" drip edge is fine, minimum. 

Gary


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## leclairk (Aug 1, 2015)

One other question I have is when I go to add trim. I'm going to use 1x4. Do I caulk both sides of the trim, where the trim butts up to the window, and the joint where the trim sits on top of the T1-11? Obviously I will need to caulk the header trim so water doesn't travel down the grooves of the T1-11 behind the trim. What doesn't make sense to me is the vertical trim. I'm going to have a 3/8" gap between the window and siding, filled with caulk backer and caulking. Then I will have a gap between the trim and the window. Do I leave a 3/8" gap there as well and fill with caulk backer and caulking? I'm going to have 2 layers of caulk backer and caulk.


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## Colbyt (Jan 27, 2014)

IMO, Yes to caulking both sides. Flashing over the window.

The rest of it I don't understand


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## Gary in WA (Mar 11, 2009)

No, two separate flashing, one -above the trim, under T1 and extend over trim; 

and one at bottom of trim - under trim and extend over window. 

As in Fig. 1c- over trim---------- and Fig. 1a over window; https://www.huttig.com/pdf/LPSmartSideFoundationsPanelSidingInstallationInstructionsEnglish.pdf

Gary


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