How do I replace a 48w x 60h exterior window with a 40w x 48h one?

Question

I am hoping to keep this structurally sound and up to code. Thanks.

Answer 1

Structurally you should be fine. Installing a narrower window does not require a new header (the horizontal structural member over the window). Installing a wider window usually does.

However, you'll have to fill in some framing and make some repairs to the siding and the interior wall finish in order to accommodate the new size. These shouldn't be too tough (unless your siding is brick or stone) but can be time consuming.

Here's a step by step guide to installing a window:

http://www.thisoldhouse.com/toh/how-to/i...

Here's another look at the project, this time with a short video clip:

http://www.thisoldhouse.com/toh/video/0,...

Answer 2

structurally you will be fine.  frame in the width of the opening with studs the same size the wall was framed with (most likely 2x4, but some walls are 2x6).  make sure you install two studs on each side as this is better for nailling you casing to.

build up you opening using a double sill plate and smaller stud blocks or build up from the existing sill plate and down from the header to where you want your new rough opening to be off the floor.

if you don't know your rough opening measure the frame size (outside to outside of the window unit) and add 3/4" to the width and a 1/2" to the height.

use the same exterior sheeting and drywall thickness.  install additional 2x's to the old crippels for backing to attach the sheeting and drywall to.  crippels are the studs that the header bears on and king studs are the studs the header bumbs into.

of course you will have to fill in the exterior finishes or install some very large exterior trim pieces around the window.

now as for code i would check with your village or city as some rooms, typical bedrooms require and egress opening of 5.7 sq. ft.,  some window units have to be a certain height above your finish floor and no higher for escape purposes and if your window is lower than 18" A.F.F (Above Finish Floor), over a tub or near a tub they may require tempered glass.

Answer 3

you already have a header for a 48w opening. no structural component to this. just frame it in with same size studs as exisiting to the required rough opening for the new window.

Hope that helps.

Answer 4

Best / easiest way is to bulk up the current frame equally with 2x4's or what ever size is currently being used in the frame.  Flush them against the frame and s***w them together.