Going to be residing with vinyl, exterior walls consist of felt over celotex (old black stuff) sheathing. Sider wants to leave felt add fanfold then tyvek & side. Leaving the felt good or bad idea ?? Jeffin pa. & I have been decussing this topic. Any opinions. I’m thinking of leaving the felt on, but as jeffin pa have concerns with all the multi layers.
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If the felt is in decent shape, I'd leave the felt and skip the Tyvek.
I would think between the siding and the fanfold, not much,if any moisture will get back to the paper. If its in decent condition leave it.
The multiple layers is no problem as long as they are all together same side and plane of the wall.
The decision is usually made by the tarpaper itself most of the time. If it still has integrity and is well nailed, it can stay, but nine times out of ten, it will be all torn up by time you get the old siding off anyways.
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Who takes the old siding off?I'm gonna post some pictures soon of a window retrofit (as part of a kitchen redo) in an aluminum sided wall. Kitchen guys hogged it in, now my friend needs the siding fixed to it.
It's a mess.....
me on my jobs. I don't know on this one at hand. Owner I guess?
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What's the point of the fanfold???
Got me... That's the siders idea, 1/4 or 3/8 sure not much insulation value. Maybe to help stop air infiltration. That's why I (we) have B.T. straight up answers from the pros with all the experience who know what's up. It's tuff though when you get different answers that conflict with each other
The purpose of the fanfold is to provide a flat surface on top of the old siding. It's the cheapest stuff available to do that. But since the old siding is being removed it's pretty much useless. (Gotta wonder about any other advice the installer gave you.)Better to spend the money (or your time) on a good housewrap job, to cut down on infiltration.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
Where do you live?
Mid. Michigan April thru Oct. 40 degrees to 90 degrees. Nov.thru March -20 degrees to 40 degrees. But who knows in this forever changing State.
But why the fanfold?
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
as I understand it, the purpose of fanfold is to smooth out irregularities in the underlying surface which providing a modest insulative barrier without adding a lot of depth. He might almost be better off using 1/2" Thermax since he is stripping the old, depending on trim detailing.
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I hear you, tell me more about this Thermax
Foil faced polyisoanurate insulation rated R-7 per inch. Can be bought in sheets 4x8 from 1/4", 1/2", 3/4". 1", 1-1/2" and greater thicknesses.I call it all Thermax because that is the first name I saw it called. I think that one is from Cellotex, but others have same product by different names.Nial it up with plasticap nails and tape the seams and you have your barrier ( except tucking at window flashing)
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Sounds interesting... Tucking at window flashing ?????
I guess that's made for exterior.. no need for tyvek than. I don't think the foil would be as strong as the tyvek but than there is the foam too.
tucking - my way of genrically mentioning getting the fenestration detailing right. I can't be specific without knowing exactly what you have. Too many vinyl guys ignore the flashing detailing and just pop J-stock against the window trim and call it good.It is good, for those of us who fix rotten framing 10-20 years later because nothing was done to keep water out at that joint.Thermax can be used on either side of a stud - inside or out.Strength is a different issue. Tyvek and Typar are made to resist wind tearouts. The foil is there to reflect btus and to hold the foam together. The panel is stiff just like the homasote on the house now and is nailed to keep it on.
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I realize the panels are stiff... btus ?? rays from the sun?? I don't know how you would tuck around Andersen casements with it being over top of the vinyl flange. How would you seal (tape) it around the window... plus the sides & bottom flanges would be under the polyisoanurate panel, they normally are on top for run off incase of a leak. I could easily see using this stuff before the windows are installed... nail it to the studs over the sheathing install the windows, tuck it (tape-seal) all flanges but the bottoms. Maybe there's a way I'm not seeing.
I can't see from here either - what sort of wrap is adressing the flanges on the windows now? Tarpaper would be my guess, but you would have to tell me before I'd have any idea.It might be too much to add this material, but they were going to use fanfold. How were they going top tuck that in at windows? Somehow, any water that gets in around windows has to be directed back out again before it penetrates the sheathing. I think that point has been made nearly ten times in this thread. How to do it depends on what is there now
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Thanks for your come back... I'll give you more information instead of putting you thru longggg distance eyeeee strainnn. All walls but two gable ends were stripped of alum. siding & windows back in 1991. The old alum. windows were replaced with Andersen casement & awning windows, wood with vinyl frame coverage, sealed only under flanges with silicone. The walls than were covered with felt (vertically over lapped 6'') & over top & side flanges of the windows. The J channel may have been nailed on first than the felt. Anyway than the alum. siding was put back on. When these walls are stripped again to replace the alum. siding with vinyl, the windows will stay in place. Which takes place first sealant tape over top & side flanges or the tyvek (or something)? I guess what I'm asking are the flanges taped to the Cellotex sheathing or to the tyvek (or something)? How can you tape the tyvek to the flange if the tyvek is over it? leave it back from the flange a couple of inches then tape? The gable ends were stripped of the siding & windows also, one last year where the whole wall was rebuilt new studs, plywood sheathing & window. The felt went on horizontally with over lap first, the modified "I" was cut for the window rough opening, a Vycor sill pan installed than the window installed & flanges taped to the felt then alum. siding put back on. The other gable end was done the same way but was not rebuilt, still has the old Cellotex sheathing, but with the felt over it, window tucking as per other gable end but siding left off, some nail holes in the felt where siding was going to be reinstall. I thought a great way to get siding back on the wall in the same place was to transfer the nail hole thru the felt & align the siding used nailing slot to it with a nail, as long as everything is in good order before removing the siding. Now you know ALL the scoop, if your still awake!! sorry this was so long. Thanks for bearing with me. I guess the fanfold was just going to butt the windows don't know how you would tuck it. Maybe the sider knows. I would just like to know if he RIGHT. The window frame only penetrates the sheathing about 1 1/4" so not much room to add much, the siding takes up 3/4" that only leaves 1/2". I think you want some window out pass the siding trim.
I have to break this up to avoid eyestrain here...Thanks for your come back... I'll give you more information instead of putting you thru longggg distance eyeeee strainnn. All walls but two gable ends were stripped of alum. siding & windows back in 1991. The old alum. windows were replaced with Andersen casement & awning windows, wood with vinyl frame coverage, sealed only under flanges with silicone.
The walls than were covered with felt (vertically over lapped 6'') & over top & side flanges of the windows. The J channel may have been nailed on first than the felt. Anyway than the alum. siding was put back on. When these walls are stripped again to replace the alum. siding with vinyl, the windows will stay in place.
Which takes place first sealant tape over top & side flanges or the tyvek (or something)? I guess what I'm asking are the flanges taped to the Cellotex sheathing or to the tyvek (or something)? How can you tape the tyvek to the flange if the tyvek is over it? leave it back from the flange a couple of inches then tape? The gable ends were stripped of the siding & windows also, one last year where the whole wall was rebuilt new studs, plywood sheathing & window. The felt went on horizontally with over lap first, the modified "I" was cut for the window rough opening, a Vycor sill pan installed than the window installed & flanges taped to the felt then alum. siding put back on.
The other gable end was done the same way but was not rebuilt, still has the old Cellotex sheathing, but with the felt over it, window tucking as per other gable end but siding left off, some nail holes in the felt where siding was going to be reinstall.
I thought a great way to get siding back on the wall in the same place was to transfer the nail hole thru the felt & align the siding used nailing slot to it with a nail, as long as everything is in good order before removing the siding. Now you know ALL the scoop, if your still awake!! sorry this was so long. Thanks for bearing with me. I guess the fanfold was just going to butt the windows don't know how you would tuck it. Maybe the sider knows. I would just like to know if he RIGHT. The window frame only penetrates the sheathing about 1 1/4" so not much room to add much, the siding takes up 3/4" that only leaves 1/2". I think you want some window out pass the siding trim.My reply-
OK here now, the most important thing regardless of all the extra info is that the flange at the botom of the window should have tarpaper or wrap UNDER the flange so water that gets in there will not be trapped behind the fanfold.
At top and side flanges, you can stop the Tyvek just shy of the flange and tape the flange to the wrap.When I place J-trim to the window, I like to caulk it with a bead before placing the trim piece so that the trim J is seated in fresh caulk. Use good stuff like Geocell and it is pretty close to welded together and chances of leak are down near zero.
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> How can you tape the tyvek to the flange if the tyvek is over it? leave it back from the flange a couple of inches then tape? Yep.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
SORRY! for the eye stain & the sloppy keyboarding... giving more info. then needed.
If the tyvek goes on first & held back from the flange then taped (top & sides) & tucked under the lower flange (if it's not sealed with silicone) if it is I guess the silicone could be cut / scraped out in spots for drainage. I don't think I would want to remove the lower flange nailing. Probably wouldn't hurt anything though atleast the tyvek would than slip under it with ease.
The water would still get behinded the fanfold but be on top of the tyvek to travel down the wall & out.
If the tyvek was on top of the flange it would be on the cellotex under the tyvek penetrating the wall.
What about the Trermax give up on that? Fanfold or Trermax with that tucking the water still gets behind it.
Grocell ... don't like to rely on caulk, but better than nothing right?
If you put any sort of foamboard over the existing sheathing you'll have to compromise one way or another on the flashing details.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
I just re-read your original post.
Since the vinyl siding is going over Celotex sheathing, I'd pull off any old felt, install new housewrap or felt, making especially sure that all the windows and doors are properly flashed. Vinyl siding really isn't all that weather-tight. The wrap needs to be done well to avoid future moisture problems.
The sider should make sure that he hits the wall studs with the nails, since the Celotex really doesn't hold nails all that well.
If desired, a layer of 1/2" foamboard could be added for extra insulation value.
The vinyl siding is replacing aluminum siding that probably has'nt been anymore weather resistant then the vinyl. 1/2" foam would mean furling out the doors & windows or something like that. Other wise they would set in instead of out. What ever that's worth.
Whatever you do, you need to have a weather resistive barrier, or WRB. That can be felt (in good shape), Tyvek, or even foam board in some cases. It doesn't really matter what you do in your circumstance as long as your maintain a continuous WRB and all the flashing details (window flashing, plumbing penetrations, doors, deck ledgers, electrical fixtures, etc.) integrate with the WRB.
I would also vote to skip the fan fold. The insulating value is modest at best, and other than that there's really no point in it for your application. If you were siding over existing wood siding, that would be another story.
Jon Blakemore
RappahannockINC.com Fredericksburg, VA