Hoping someone else out there has applied vinyl siding directly over 1-3/8" or 1-1/2" rigid foam.
If so..did you use nails or screws?
Would really like to hear the 2 cents of anyone with an opinion.

I have used screws over ICF and it really did not slow me down that much..but the screws do get expensive for something with a rust resistant coating....figure to use 3" screws (1/2 plywood sheathing)

I really don't want to install strapping over foam to attach siding....
 
zone 5 with 2x6 construction.. need r-7.5 for IRC 601.3.1......Just looking to reduce thermal bridging and boost R-value some not getting to crazy it is just a garage/shop

Thanks all....oh and the name...it's from my midlife crisis  AT hike I really should change it but dont know how

over the weekend I did a model of vinyl siding over 1.5" rigid foam on a side wall of the addition. I attached a sheet of polyiso to the wall and put a 4' high section of vinyl up over it. I am happy to report that I am confident it will be secure enough. I used 3-1/8" all weather cabinet screw from GRK. I used a shorter version of the same screw several years ago on ICF vinyl project and the low profile flat head was perfect for the project.
The screws can flex when pushed on individually ( as expected) but as a system with several in a row in a piece of vinyl they are rigid enough. Perhaps 1 size thicker diameter screw would be better (cannot find one) ..but for sure it is far stronger than the roofing nails I also tried.

Still need to finalize my flashing details for windows...thanks to another blog I have a pretty good idea how I will do it..with 2x stock behind the window flange.
Has anyone nailed the windows directly to the sheathing and simply used thicker details on the window trim to make up the difference? Just like old houses which are being re-sided with vinyl which have old square 1x stock for trim with a band molding around the outer perimeter... I may try to make up a model for that next.

so I was messing around on the workbench with one of the windows from my project. Here is what I have been thinking...
I am pretty cautious about waterproofing my window installs for customers....I have kept plenty busy during this recession  fixing builders leaking windows from poor installs (reverse lap wrb, no drip cap, no wrb at all...etc) But I have a tendency to over think sometimes.

The way I see it if my windows are installed as "innie" with the nail flanges against the sheathing and flashed properly with generous projecting drip cap on top to shed water away that is my fail safe wrb (if there were no rigid foam then the only wrb)

 I plan to install 1.5" polyiso with taped seams on top of that wrb and leave a 1/4" gap around the windows. since the window exterior projection is only 1.25" that leaves 1/4" of exposed foam projecting beyond the face of the window frame. My Plan is to bend up some aluminum trim to cover the entire edge of the foam which abuts the window to give it a finished look.
 Next, caulk that junction of aluminum trim and window. Now this will be my secondary waterproofing system (I know relies on caulk but, that what Anderson install specs say anyhow.

Now the vinyl j-channel goes around the window installed properly to channel most water away. The vinyl being first line of defense in the system.
I should add that there are generous overhangs from the roof above all windows and it has rained for a week straight here and no water has entered the exposed openings

Now this idea occured to me when I was putting away the information for the insulated vinyl siding which I had been looking at. I realized that system simply relies on the first line of defense wrb on the sheathing and the vinyl siding itself and thats it. Perhaps that XPS foam dries should water get behind it but at the same time it has lots of untaped seams for the water to get in and under to begin with.

Most of my research shows details for wood or hardi siding over foam...Not much about vinyl...As I said sometimes I over think these things and sometimes I miss the obvious.

Any comments are very much welcome.

Thanks

I'm assuming your considering this to save on jamb costs?

Instead of bending coil, which I find to dent easily and a big pain in the ass, you could rip the front of a piece of j-channel and install backwards to cover the edge, much like you do on walkout basements where the sheathing meets the concrete.

Other than that, you have 2 sealant beads to maintain rather than 1 and the some will not like the inset look it will provide, but the concept is the same, a flashed drainage plane exists as if the foam wasn't there and the foam becomes a secondary drainage plane.

Update, This was project was completed last summer.
I ended up installing 2 windows as "innie" but hated the look and pulled them back out.
I changed it to "outtie" design and followed Greentree advice he provided elsewhere to fir out window frame with 2x stock covered with flashing. I have had no leaks (interior of project still not completed so easy to tell)
I am going to try to post some pictures of the install....stay tuned.
Also, I installed the vinyl on project over the 1-1/2 foam with a combo of screws and hot dip galv nails. I used vinyl which was top grade thickness and very rigid and locks together very well. The nails were a lot easier to deal with and it survived a minor hurricane here last fall.
The rigid vinyl was a big help when installing as a 1 person crew.

FreakBoy ...
I know this is years later ...have you modified your 1.5" insulation approach?
Are you still using those GRK 3" screws ?

my approach:
1. 1/2" plywood sheathing
2. 1.5" XPS ridgid foam
3. Tyvek WRB on TOP of the insulation
4a. Siding
4b. Windows

Windows installed directly over the Tyvek as Outies, no blocking for the windows anywhere for the windows . Flanges caulked underneath before windows are nailed. 3" or 4" flashing tape on top of 3 sides of windows flanges .
PVC trim boards around windows. No caulking needed between trim and window since the WRB and flashing tape is quite secure. Allows any possible water entry to drain down side of window.
Drip edge over windows only for double hungs since the window flanges are removable and have a water entry points. . Awning and casement windows (Andersen) have molded one piece flanges so no drip edge needed.

Hey there, Hope I can provide some great follow up on your questions. But first off please take this advice from a remodeling carpenter who sees a lot of water damage on homes.
DRIPCAP IS ABSOLUTELY NEEDED. for 3 reasons.
1. install it with a slight slope so water runs off the front and drips in front of window and therefore does not run off sides or pool on top (if installed flat as I was taught back in 80's). I make my own dripcap and make it 1/8 inch deeper than window so water drops in front of window.
2. Nain flanges crack.....indeed I have seen 400 series casements installed by others which were badly cracked and leaking (along with a horribly damaged drip cap)
3. Anderson absolutely requires it on all window directions.

now that the important thing has been addressed....for the rest of the questions.
I have only done foam/vinyl 3x so take my advice as only part of your research.
1. The first time was 10 years ago for a friend and the framer had installed the windows right on top of 1" foam......there have been no issues that I am aware of with that project. I did install dripcap/flashing tape followed by strips of tyvek over every window and door penetration up to the soffit/roof level and nothing has ever leaked........despite the fact framer did not caulk window flanges on install.

2. 2nd time I did foam/ vinyl I installed tyvek over 1.5 inch foam on entire structure and feel it best procedure. I originally used the GRK screws but switched to 2.5" galv roofers after 1 side because it is way faster and cheaper......no problems I know because I still live here. I did use a much stiffer/thicker/higher wind resistant vinyl than usual because I was paranoid about the 1.5" inch thing.......I would probably do the same again. The vinyl was Mastic Quest.

I always back up wide window flashing tapes over foam with a strip of tyvek tape (or staples on wood as Vicor requires if one bothers to read online directions for the product)......I have seen flashing tapes peel back many times over time.

Again, search for Mike Guertin article in JLC or Fine Homebuilding on cap flashings if you don't believe me.

hope I could help

1 more thing
ants love foam for nesting. I have had 2 nests started in different areas which I was able to stop in my 1.5" foam......

I have also had ants start nests in 6" of roof top foam 2.5 stories up.....that really sucked.

now I spray for ants constantly despite the environmental problems spray may cause.

RE: I have also had ants start nests in 6" of roof top foam 2.5 stories up.....that really sucked.

Amazing how these critters go so high up ...

RE: Drip edge over windows ... all my window installs so far have been on houses with wide roof overhangs which = minimal amounts of water ever reaching window tops ... but I do hear you .

RE" 2.5" roofing nails ...
I use the same with 1.5" XPS ...
nail tip protrudes 1/4" through 1/2" ply ...

Thanks for the updates .