Do You Really Need Foam Board Under Siding

Below are some of the design details along with the benefits of installing exterior rigid foam board insulation.

Do you really need foam board under siding.

Today more than ever before homes are being built with foam board insulation installed on the outside of the sheathing and under the siding. Installing foam insulation under vinyl siding is a wise choice for homeowners who are seeking to protect their homes against moisture infiltration as well as improve energy efficiency. This allows vinyl siding manufacturers to make insulated siding in wider flatter profiles and richer darker colors than before. With budgets tighter than ever now contractors and do it youselfers are tearing off the original siding and installing a thin foam board underneath claiming it will improve the energy efficiency of the property.

But if you use wood clapboard siding foam sheathing can cause trouble. The answer happily is yes. In reality rigid foam board which sometimes comes in fanfold usually only has an insulating factor of r 1 and does not add any appreciable insulation effect to your home. In fact the two products combined make your home super insulated from outside wind and weather.

If you choose to install house wrap with rigid foam generally it should go under the insulation not around it. This detail is used with both new construction and also with renovation work. In a typical situation. Moisture can get trapped between the siding and the foam leading to paint failure and causing clapboards to cup and curl.

And even though some manufacturers call it rigid foam insulation for the purpose of vinyl siding it basically has the same insulating value as a piece of plywood. Many people install vinyl siding or concrete board sding to improve the look and value of their home. It also serves as an air barrier.