Rigid Foam Insulation Over Wood Siding

Readers are constantly asking if the rigid insulation is supposed to be installed over the building wrap or vice versa.

Rigid foam insulation over wood siding.

We have a historic house that is undergoing a deep energy retrofit with rigid insulation being applied to the outside and then strapping and new siding. Moisture protection and heat buildup. One of the most asked questions on our site is related to this article. How should wood siding be installed over rigid foam insulation.

The nails have a plastic cap that keeps them from damaging the foam. Rigid foam over building wrap. Last year i installed lp lap smart trim shingles and the 4x8 sheets of lp with batts all over 3 of continous xps foam using fern strips. Always follow the manufacturer s instructions for installing rigid foam insulation.

When applying james hardie siding directly over the combined thickness of foam sheathing continuous insulation and other non nailable substrates e g. He would like to keep it on and simply put the new rigid insulation over the siding. It seems this will create some nice air pockets which be. To secure the foam use two inch cap nails.

Many houses built today have a double wall type of insulation with fiberglass batts fastened between the studs on the inside and rigid foam board over. Plus rigid foam insulation applied over the outside walls. The contractor has ripped off a few layers of asphalt siding and is now down to the original siding. Fit the rigid foam insulation snugly and seal all.

The foam on the outside keeps the wood frame inside the wall warm and dry in. Some people use roofing nails but if a strong gust of wind gets under the siding it may not hold. What are the risks of installing cedar siding directly over foil faced rigid foam insulation should tar paper or housewrap be used as well. Cover the house walls with 4 by 8 foot sheets of rigid foam insulation typically 1 2 to 1 inch thick nailed to wood sheathing with 1 1 2 inch broad headed galvanized nails every 16 to 18 inches.

Siding over rigid foam. Well call me half hazard. How to install rigid foam under siding. Of course i did this all knowing my warranty would be void.

With foam sheathing an air space is essential both to reduce the siding s water uptake and to provide a. When installing wood siding over rigid foam sheathing you must protect the siding from moisture and heat buildup and use proper nailing. Lp siding with fern strips over insulation. Since foil faced foam is a moisture barrier it should be used with a continuous film vapor retarder on the inside wall.

Gypsum sheathing up to 1 inch thick the foam sheathing and other non nailable substrates do not have nail holding capacity. Is replacing wood siding with vinyl and.