Need help sorting through installation methods!

[co172]

I apologize for the length of this post in advance. I'm just now doing my homework on installation and I am quite torn with my choices. For reference, my home currently has aluminum windows and is wood sided, but has 2-1/2" x 3/4" trim pieces around all windows (this is original, not from another window install). See the 3 image links for a basic idea of what I am talking about.

Pic 1

Pic 2

Pic 3

I read Tru_blue's comments about the 3 installation methods in another post for background before writing this.

It seems that 95% of the installers in the Seattle area want to collapse the frame and use the 'screw and glue' approach for retrofit installations on my type of home. I was originally ok with this, but am worried about the windows leaking as the caulk ages and begins to separate. Also, my windows would end up being caulked to my trim boards which are in turn caulked to the siding and this gives another potential path for water to enter if the caulk fails.

Another installation method leaves the aluminum frame and uses a 'flush fin' type of window as an insert which is sealed with caulk to the old aluminum frame. I would trust this much more than the proposed 'glue and screw' method, but I have some quite skinny windows which will become abnormally skinny due to the extra leftover aluminum frame width. Is ther a way to circumvent this loss of glass area?

So that covers 2 methods. The last method is the new construction method that uses the nail fin. I am 100% dead set against pulling any siding off my house, however, I am not against pulling off the 2-1/2" trim boards to allow for a new nail fin. I am not sure, but I don't believe that 2-1/2" is enough room for a nail fin and the appropriate flashing. I've heard of simply using beads of caulk underneath the nail fin edge, but have been told that this is not as reliable as the flashing method. Can someone tell me if 2-1/2" is enough space to perform a reliable nail fin installation?

Can someone also comment on the other 2 installation methods to tell me if I missed anything? Will the simple 'screw and glue' method be acceptable if a yearly caulk inspection is performed? Please help me decide on the best route for my needs!

[randy]

Your situation is common here in Texas, and we typically collapse the frame.

I recommend you have the installers use a minimal expanding foam around the window before sealing the exterior. This way you will have an inside and an outside layer of sealant with the foam between them.

If you are going with a vinyl window, the frame depth is typically 3 1/4", which means your installers will have to cut your sheetrock or wood jamb returns back to allow the window to be recessed in, to prevent them from extending outward past your siding. There will be enough space to foam, I'm sure.

Obviously, the very best method is the new construction route, with nailing fins, but when this is not possible, we use expanding foams to back up our sealant.

[Guy]

With all your windows having that trim around them I'd say it's an easy choice. We will always remove that trim very carefully to access the nailing fins of each window. We'd then remove all the fasteners in the fin and pull the entire unit. This way we can check for any problems which they may of had in the past. Then we install the window with a nail fin and get the best protection available to the customer. After the frame is nailed in place we can tape the outside fin and re-nail the trim boards back in place. We'd fill the nail holes and caulk the outside up completely.

The inside would get low expansion foam with new jamb boxes to finish them off. It requires a little more work but offers great protection. jmo

[Tru_blue]

With that 2-1/2" trim in place it makes the installation decision a no-brainer, at least for me. I'd remove the trim so that I could gain access to the installation fins and then completely remove the old window and do it right. How fortunate that the trim is there. Not only does it add some visual "punch" to the home but makes it easy to remove the old windows (relatively speaking). Then you can use the nailing fin and seal it to the opening. Fins are usually either 1-1/4" or 1-1/2" wide, so they will easily fit into the space vacated by the 2-1/2" trim and still allow for sealing the fin to the sheathing.

As the others mentioned I'd use a low-pressure foam to insulate around the window; just make sure it's low expansion and not high expansion. Some installers would not put new insulation around the window if you have a drywall return up to the current window because the drywall would block access to the rough opening perimeter from the inside and the nailing fins would block it from the outside. As Guy mentioned, one could insulate around the windows and install "new jamb boxes to finish them off."

By the way, that freefilehosting.org site that you used for posting the pictures is a nice resource - I'll have to jot that one down.

Here's a link to the previous but similar discussion
viewtopic.php?p=3396&highlight=#3396

[co172]

Thank you all for your responses. I half expected that was the correct choice. A couple of questions about using the nail fin then:

1) Does the window have to be shimmed at all when using the nail fin method? I am assuming not, so then how much extra space should I ask for between the window and the rough opening to allow for foam? 1/4"?

2) When reinstalling my 2-1/2" trim boards, they will have to be installed back over the nail-fin. This makes it pretty much impossible to install them without putting additional nails through the fin. Is this acceptable practice?

Incidentally, I found what I think is decent video clip explaining window flashing installation. Your thoughts?

http://www.hgtvpro.com/hpro/pac_ctnt/te ... eoid=66905

-Colin

[randy]

My prior advice was slightly off track, as I made an assumption that the siding would be under the trim boards, when I should have looked at the photos provided before offering my opinion. Sorry about that.

Here in Houston, the siding is typically ran up to the window, and the trim is then installed over the siding, up against the window.

Your situation is obviously different, therefore, I concur with Guy and Tru_Blue, use the nailing fin application, and if necessary replace any damaged or cracked trim boards.

[oceanengineer]

For a replacement window in siding I see that the nail fin is the best approach, especially for new construction. How much of a hassle does it create for a replacement window when the window depth may not match the window it is replacing?

My windows have a wooden box between the current aluminum window and the drywall so cutting it back may require a lot of drywall replacement/repair or gap filling. Also, can it create issues with the position of the window with the siding as the window position (in-out) would be dictated by the position of the old studs - I guess they could always be shimmed.

Also for Simonton tyoe windows do you expect to pay a lot more for the nail fin compared to window without in the Prism Platinum or 5500 series?

[randy]

Without seeing the wooden box, it is hard to answer. I am guessing, however, that the wooden box you are referring to is nothing more than a piece of lattice trim or a piece of jamb extension, that has been installed over the sheetrock. That is not so uncommon here in Houston, although, for the life of me, I can't understand why some builders did this.

If this is the case, the trim can be removed and reinstalled, or better yet, get some vinyl quarter round to trim out the interiors of the windows. This can actually look very nice, when done, and somewhat looks like a wood window.

I'm not sure of the upcharge for a nailing fin on the Simonton, but would not expect it to be more than $8.00 per window.

[Bill]

The nail fin will add about $16.00 to the cost of the Simonton

Bill

[oceanengineer]

Thanks for the response guys - you really help make our decision making much easier.