I'm at the point of installing new construction vinyl windows in my house and I am uncertain about two aspects of the installation.
1) Caulk behind the window fins; yes on no ?
The manufacturer says yes, but in an article on BuildingScience.com, it states that it is "unnecessary and dumb".
With proper flashing, it does seem kind of redundant; sort of like wearing a belt with suspenders.
What say ye ?
2) Nail the fins tight or nail loose like vinyl siding ?
The manufacturer say loose to allow for expansion, but even when nailed loose, I wonder how the vinyl can expand and contract given the orientation of the nail slots. In other words, the side fins have vertical slots, supposedly to allow vertical expansion of the window, however, the top and bottom fins have horizontal slots which would seem to interfere with the vertical movement of the window.
The same could be said about the horizontal movement of the window. (Top/bottom slots inhibit vertical movement; side slots inhibit horizontal movement)
What say ye to this ?
Thanks,
Arky
If you are using "grace" or equivilant (should be) then caulking will not provide any additional advantages. On mine I did nail them tight. Right/wrong they don't seem to be causing any problems.
I say no and no, i nailed mine tight and used silicon along the seams.
Lets see what some other members think.
If the manufacturer states caulk in certain places and you don't that may affect any warranty claims. Needing warranty is not likely. The most common warranty claim is likely the sealed glass units developing leaks and you're not going to have to provide proof of caulking the fins for that. If everything is flashed correctly the caulk is probably not needed. If you worry about that stuff then use a small bead. If the windows ever need removal for a renovation/repair the caulk behind the fin does make that more difficult.
FWIW, I laid a small bead of sealant to the wall before installing my windows. Then self adhesive flashing working bottom up. I figure one is insurance for the other.
I used a few screws and mostly nails. Not real tight, not loose.
Quote from: Arky217 on March 25, 2011, 12:30:06 PM
I'm at the point of installing new construction vinyl windows in my house and I am uncertain about two aspects of the installation.
1) Caulk behind the window fins; yes on no ?
The manufacturer says yes, but in an article on BuildingScience.com, it states that it is "unnecessary and dumb".
With proper flashing, it does seem kind of redundant; sort of like wearing a belt with suspenders.
What say ye ?
2) Nail the fins tight or nail loose like vinyl siding ?
The manufacturer say loose to allow for expansion, but even when nailed loose, I wonder how the vinyl can expand and contract given the orientation of the nail slots. In other words, the side fins have vertical slots, supposedly to allow vertical expansion of the window, however, the top and bottom fins have horizontal slots which would seem to interfere with the vertical movement of the window.
The same could be said about the horizontal movement of the window. (Top/bottom slots inhibit vertical movement; side slots inhibit horizontal movement)
What say ye to this ?
Thanks,
Arky
So the manfu. says caulk them in but nail them loose. Ah, if they are caulked in how can they move to expand IF they are nailed "loose"?
If your flashing and / or Vycor taping the window properly the caulking is not needed.
If your plan , (which from your question I highly doubt you're planning on doing ,) is to not detail the flashing properly or bother to do , flashing, at all there's no sense caulking anyway, as the water will get in some where and rot something out anyway! One thing that won't rot is the window itself LOL .
What I do is nail the window tight , or as snug as you can , IF you attempt to "nail-er hard" the nail flange will break , so I'll call it snug nailing.
With proper detailing I do NOT caulk the windows in.
I do follow the Vycor recommended sequence , sill first , set window , sides lapped by at top and bottom , flip back the building wrap , run the last Vycor strip over the head flange ( no nails in the head flange BTW) that laps the side Vycor. Flip back down the head building wrap over the top Vycor , small "patches" over the two angled slices in the building wrap.
Seals out water and a lot of the air , inside you stuff the crack at / between the RO with the insulation rope blocking the remained of the air leaks.