Hi all,
We are aiming to install cedar shake siding on an approaching job and are looking for some input from others with experience here.
The task remains in zone 6 in Canada, so it will get cold winter seasons and hot summertimes.
We are seeking to use Zip-R9 as our sheathing and WRB layer for the constant insulation benefit. We took a look at doing rockwool over plywood but were recommended against it given that it could produce waves with the shakes. So we have to do with 80% set on moving ahead with Zip here.
We do a great deal of siding details, however not a lot of shake. With siding, we strap the wall with furring to get our rain screen/P. E.C.
. Now with cedar shake, we can either do cross strapping of 1 × 4’s, but this is a more labour extensive route and can be a pain for detailing at openings and so on. Or we can set up the cedar over Ventgrid 12 to get our rain screen.
We were initially sold on utilizing Ventgrid considering that it is less labour. However, with ventgrid every nail used to fasten the shakes would permeate the Zip sheathing. With strapping, the shakes would attach to the horizontal straps and not penetrate the zip sheathing.
We are worried that having so many nail penetrations going into the zip sheathing might be a problem long term for air sealing and water damage. We were seeking to utilize densepack cellulose and the insulation, so if water did get in that would be a huge issue. We might switch to rockwool batts though as a counter procedure.
The contractor does a wonderful job of installing zip effectively and with their tape/flashing information. So I am not worried about the basic installation of the zip. It is more so the cedar shake penetrations, which can not be taped or flashed that stress me.
I understand this occurs with roof all the time, but roof sheathing is acting more as a water shedding layer than an air barrier, so its a little bit of a different monster.
Are we overthinking this? Does anyone have any experience with this that could help in this situation?