Foam Board Under Fiber Cement Siding

In a typical situation.

Foam board under fiber cement siding.

If installing their fiber cement siding directly over rigid foam they do not recommend any more than 1 of rigid foam and they seem to prefer no more than 1 2 of rigid foam the main concern being that the nails will sag if driven through anything thicker than 1 of rigid foam. Exterior rigid foam w modern hardie plank siding details. Addition to my house. We show z flashing below the first course of siding and we show perforated board.

According to my calculations if i want to use rigid foam insulation on the outside of the 2x6 walls with r 21 fiberglass in the wall cavities i need at least r 11 25 in order to avoid condensation on the inside. Perhaps a few pro s on this board could elaborate as to the main reasons why. I ve become a big fan of utilizing outsulation on all my houses over the last 2 3 years. February 13 2013 exteriors insulation air sealing siding.

But if you use wood clapboard siding foam sheathing can cause trouble. I d like to side it in fiber cement siding to match the existing house. It gives another element that wants to be fiber cement or another rot resistant material. Alot of guys do not favor any insulation under fiber cement though.

Almost any type of siding can be installed over the rigid foam cedar or redwood planks exterior plywood sheets cement fiber board or vinyl siding are common options.