Tips for replacing windows

Old 01-27-16, 03:19 PM
Thread Starter
Join Date: Jun 2013
Posts: 32
Upvotes: 0
Received 0 Upvotes on 0 Posts
Tips for replacing windows

I am replacing my old aluminum windows throughout my house with Milgard vinyl. I have never replaced a window before and while I think I have a good grasp on the big steps, the little ones I am not so sure of.

the siding goes right up to the window edge so I am going to saw around the window, yank the old and replace with the new construction window and then add trim.
Name:  Pic1.jpg
Views: 384
Size:  24.9 KB
1. Do I need to put any caulking behind the window flange before I secure it?
2. What type of fastener should I use? I've seen people online say they use nails or screws - which is proper?
3. Do I need to put any house wrap/flashing on top of the nail flange?
4. When I install exterior trim around the window (1x4 cedar) what is the best type of nail to use?
5. When caulking the exterior trim do I put caulking between the trim and window or just between the siding (lap cedar) and the trim?

Any other good tips to know? Thanks!!

Last edited by yosamitysam; 01-27-16 at 03:42 PM.
Old 01-27-16, 03:38 PM
Join Date: Jan 2011
Location: USA
Posts: 4,459
Received 125 Upvotes on 110 Posts
#1, no one on any web site can see what your seeing, need pictures inside and out.
No close up's needed!
We have no clue what type siding you have or how you plan to trim them out.
Old 01-27-16, 07:51 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 26,394
Received 1,743 Upvotes on 1,567 Posts
When you cut your windows out, (assuming you are using a sawzall to cut along the edge of the window,... between the window and the wood siding and leaving the old nailing fin behind your wood siding) you will be left with a just rough opening and no framing to attach the new window to.

I think you will find that the nailing fin of your current window is behind the siding which means the stud is behind the siding. If that's the case, you will need to ADD a stud around the entire perimeter of the opening in order to have something to nail your new window to. (It would also mean your new window would need to be at least 3" smaller than your existing window). If your new window is exactly the same size as your existing window AND it has a nailing fin (making it larger overall than your existing window size) that would mean you will need to cut the siding back in order to expose enough of the sheathing so that you can nail the window on. In that case you would set your skilsaw about 3/4" deep and saw around your old window, staying about 1 1/4" away from the window edge. Can't say which... since we don't know the size of the old window nor the size of the new one.

1). You "can" caulk behind the fin, I usually don't because I use flashing tape to cover the fin. (Sides and top)
2). A hot dipped galvanized roofing nail will usually lay the flattest, which is why most window installers use them. Others used screws because they are afraid of using a hammer around a window for fear they might hit it.
3). Housewrap should already be on the house. If it isn't, do you plan on taking off all the siding and adding one? Since the answer to that question is usually no, that's where flashing tape is useful... to cover as much of the exposed perimeter as is possible right up to the siding. The top of the window should be flashed behind the siding either way. This is normally done by putting a drip cap (z-flashing) over the top of the top piece of trim.
4). Best type of fastener with cedar is stainless steel. Stainless steel finish/siding nail or a S.S. trim head screw. 2nd best is ceramic coated ACQ type finish screws, 3rd best are hot dipped galvanized finish nails.
5). Caulk between the siding and the trim and also between the trim and the window.
Old 01-28-16, 03:20 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 36,608
Upvotes: 0
Received 9 Upvotes on 8 Posts
Brant, is that wood siding or D5? Looks too smooth to be wood.
Old 01-28-16, 05:14 AM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 26,394
Received 1,743 Upvotes on 1,567 Posts
I think he mentioned toward the end (in #5) it's lap cedar. Smooth cedar clapboard. You can see the indentations where it's been nailed.

I was also thinking, the op mentioned using 1x4 trim. If you cut your siding back 3 1/2" from the window, the end of your siding will no longer be nailed to a stud. I would suggest either 2" brick mould or a 1x2 trim such as LP Smarttrim. The 1" thick variety would be best. (5/4... pronounced five quarter).
Old 01-28-16, 05:32 AM
Handyone's Avatar
Join Date: Aug 2000
Location: U.S.
Posts: 4,807
Upvotes: 0
Received 0 Upvotes on 0 Posts
I replaced all my windows with new construction. The house is stucco, so your job will be a little easier with wood siding.

XSleeper covered it all, but it would be nice to know if your new windows are the same size as the old.
I don't want to repeat what X laid out, but I would remove the old windows, flange and all.
Also be careful with the old flashing and keep it intact as much as possible. The new flashing will go over the old, but the old gives you some insurance against leaks, since it's wider than the new tape you'll be applying.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: