# How to replace aluminum with vinyl windows on T1-11 siding house?



## Tom Struble

is there sheathing or paper under the t1-11?

you would install a metal Z flashing under any paper and over your head trim..generally speaking


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## 211

Tom Struble said:


> is there sheathing or paper under the t1-11?


No the t1-11 is nailed directly to the framing. No vapor barrier or anything. There's a corner of the t1-11 on the back of the house that's coming loose at the bottom corner. I can pull the corner back and see 2x4 and insulation. 

Yeah, this is an old '70s built "vacation" home with 2x4 exterior walls. Obviously thermal efficiency was not a concern then.

~EDIT~
I just came across this DIY with decent photos. This is more or less the procedure I had in mind for the R&R or the window but my concern is still flashing the top trim piece. 
Unfortunately not all of my windows are under a soffit like in the DIY so proper flashing would be crucial.


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## Tom Struble

just remember you can't ''seal'' horizontal joints like window heads with caulking,you need metal that goes behind the siding and then out to daylight over trim

you can do the same type of thing at the sill,if there is no paper under the siding i would install a sill flashing that drained directly over the top of the t1-11


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## 211

Tom Struble said:


> you can do the same type of thing at the sill,if there is no paper under the siding i would install a sill flashing that drained directly over the top of the t1-11


This would require removing the bottom nailing flange on the window wouldn't it?


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## Tom Struble

no,not necessarily

if your cutting back the siding for the flange,you can install the z at the bottom of the cut,wrap your sill flashing over it then install your window 

the idea is you want drainage to be over the siding instead of behind it


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## Tom Struble

this is the idea but in stucco,notice the metal bent over the stucco,the self adhesive flashing brought down over the flashing and the trim installed over the top


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## 211

Thanks for the photos. I'll get a closer look when I get home.


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## 211

I guess the other thing I should mention is...
I'm open to other thoughts or ideas. It seems 50/50 whether people install the windows over or under the T1-11. 
Under sounds like a lot more work. but over seems like it would be hard to flash around...

I dunno...
For as common as a project like this seems, there's not much "solid" info available.


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## kwikfishron

> I'm open to other thoughts or ideas. It seems 50/50 whether people install the windows over or under the T1-11.
> *Under sounds like a lot more work. but over seems like it would be hard to flash around...*


It's really pretty simple, do it fast and easy and rely on caulking to keep the water out or spend a little more time to do it right.



> For as common as a project like this seems, *there's not much "solid" info available.*


TS just gave you "solid info", sorry if it wasn't what you wanted to hear.


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## Windows on Wash

kwikfishron said:


> It's really pretty simple, do it fast and easy and rely on caulking to keep the water out or spend a little more time to do it right.
> 
> 
> 
> TS just gave you "solid info", sorry if it wasn't what you wanted to hear.


+1

Tom just laid out the plan for you right there.


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