In an un vented roof foam can serve as the air barrier and vapor retarder and prevent moisture from getting in to the roof.
Foam board roof vent.
Intended for a roof pitch of 6 12 and higher it is recommended to use the cv3 vent for a roof pitch of 5 12 and lower installed without cutting or altering the roof structure made with fiberglass screen making it a mold and mildew free permanent solution to your ventilation needs while providing over 7 sq.
No more foam flapping in the wind.
Some people nail flat 2x4s on top of their existing roof and build a new roof to create a vent space but it would be hard to justify the cost for a workshop.
If you want to install rigid foam above your roof sheathing in climate zone 3 then 1 2 inch of rigid foam board is not ideal this rigid foam layer needs a minimum r value of r 5 and that s impossible with 1 2 inch of foam.
Attach the tongue and groove insulation boards to the concrete wall with adhesive.
Today there are more options.
Rigid foam and spray foam are two of them.
Use a premade kit for this type of project.
We used 25mm on the roof of our sprinter van conversion and 40mm thick board in the walls.
Vent a foam insulated roof there used to be a time when the only insulation available was pink fiberglass.
The plyco quick vent is non wicking highly pliable while still providing a superior airflow.
All insulation materials require proper venting.
Additionally raft r mate attic vent has an optional bend down air stop or insulation block at the top plate of the wall in one easy to install product.
Cathedral roofs especially need a lot more insulation between the ceiling and the rafters because there usually isn t.
So an unvented roof is probably your best option.
Owens corning raft r mate attic vent is an extruded polystyrene foam vent designed to assure unrestricted airflow from the soffit to the ridge vent.
Simply peel the backing and install.
Just peel the backing as you install.
For new construction use rigid boards to insulate slabs and the outside of foundation walls.
Plyco quick vent comes in 2 x 10 lengths for quick and easy installation.
In a vented roof foam can seal the openings and serve as an air barrier and a vapor retarder in addition to its insulating function.
Foam board insulation with rigid panels polystyrene and styrofoam boards are low cost and quick and easy to fit to the large panel in the camper van.
Of airflow per linear ft.
Foam insulation can play an important role in both vented and un vented roof assemblies.
The superior adhesive helps make a complete seal.