Do You Need A Vapor Barrier Under Lp Siding

Moisture barrier requirement beneath vinyl siding.

Do you need a vapor barrier under lp siding.

Vinyl siding is one of if not the most popular exterior cladding for residential homes. What s more you re in an area of the country where you probably need to put the vapor barrier on the outside of your addition. If you live in climates zone 5 6 7 or 8 most building codes require a vapor retarder a less stringent barrier than a vapor barrier on the interior side of the wall assembly. In the end the decision to install house wrap under your siding is a personal one that you should make after discussing it with your contractor.

There is no logical reason not to have house wrap under vinyl siding and many authorities strongly agree that it should be viewed as mandatory even if your local building codes don t necessarily require it. But this wrb is not a vapor barrier. Wrbs including tyvek are vapor permeable. Sources of leaks into a vinyl sided building.

A wrb is more of a water and moisture resisting barrier than a vapor resisting barrier and it also serves when installed correctly as a drainage plane for water and moisture get behind the siding as will happen. However if you re interested a residing project offers the perfect time to examine your home s weather barrier and exterior insulation and improve it if need be. A wrb is to varying extents a vapor retarder but not a vapor barrier. They will breath and excessive moisture should escape through the exterior siding.

The installation instructions explain that smartside is installed with nails or screws not adhesive. The bottom line janice is you need to remove the cement siding and install some sort of house wrap that has the drainage channels. You don t want a vapor barrier in this location. Vapor barriers vinyl siding.

If you plan to build your shed on a concrete floor a plastic barrier under the slab will prevent moisture from entering through the concrete. Third a true vapor barrier is installed on the heated side of the wall studs not under or over the exterior sheathing. Whether or not you need a vapor retarder hinges on three main factors. Why do homes need house wrap.

Not every wall does. Do i need a vapor barrier in my shed. A shed without heat and air conditioning does not need to have a moisture barrier as it will cause condensation and mold growth. The wall cavities and insulation must have a a way to breath.

Housewrap vapor barrier requirements for vinyl siding article contents. According to the installation instructions for smartside siding lp smartside 76 series lap siding may be attached directly to framing members spaced up to a maximum of 24 in 600 mm on center so you don t need any sheathing under the siding.