i do just this on just about every house i build or renovate. just be sure to be using 2 1/2" siding nails to nail through the nailing flange and make sure you order the windows with hurricane clips so to fasten the unit to the framing in the rough opening

 

So, you don't necessarily need a replacement window when putting in windows with rigid foam?

 

When installing the foam,I leave very little space between the material and the board or floor. If there is any space left ,I caulk or tape it to ensure maximum insulation.

​

 

When installing the foam,I leave very little space between the material and the board or floor. If there is any space left ,I caulk or tape it to ensure maximum insulation.

And foam it in also

 

if your going to caulk the window in place thats on top of foam make sure the caulking is compatible. many polybeutyl caulkings will eat the foam

 

So many choices, why is there rigid foam?
Here we use 2" foam and stucco all the time. And then the choice is, are we replacing all the windows, are we trying to match a existing window detail.
There really is not a right or wrong way.

What existing exterior siding and window trim detail do you have that you want to match?
Oh yeah, pics do help.

 

The extension jambs are for any window where you need them. It is for trimming the interior as needed. Some people will do gypsum returns with vinyl windows but a window, particularly a prime window, always looks better with extension jambs, a stool, and casing.

 

When you have exterior rigid foam in addition to the sheathing should you apply the house wrap before the rigid foam directly to the sheathing or over the rigid foam? My thinking is the house wrap needs to be the last line of defense against any possible water getting in so I would fasten directly to sheathing. But if you do that you should integrate the house wrap with the flashing, therefore, the window would have to go in before the rigid foam, correct?

 

There are different schools of thought on that whether it is an innie or outie wrap.

As long as it is done right, it doesn't matter.

 

no.. the window goes in after the foam is installed. it goes right on top
depending on the type of foam used and the method its manufactured you may not need house wrap. type 2 foam that has a shiplap on it does not require house wrap in some regions.. as the ship lap acts like a flashing so any water that runs down the wall wont leak in and get at the sheathing

 

Kirk,

I agree to the extent that the outie install makes for the cleanest look and most seamless installation but there are situations (and they can easily be flashed an accommodated) where you can set the window tight to the sheathing and create the box detail on the exterior.

Not my favorite but I have seen it done properly in retrofit applications as well as new construction.