Fanfold Insulation For Vinyl Siding

Dupont has said on their website and product flyers that if using both fanfold and housewrap and committed to both put the tyvek housewrap over the fanfold but they actually recommend assuming the insulation is totally closed cell with very low absorption rate putting the insulation directly under the siding overlying dupont drainwrap which is designed to provide a better drainage path between the two than regular housewrap.

Fanfold insulation for vinyl siding.

Fanfold board is worth the cost and effort to install behind vinyl siding. The exterior insulation also helps keep the siding all vinyl siding leaks further away from the exterior sheathing. Fan fold is typically sold in 1 4 inch by 4 foot by 50 foot sections and is installed horizontally across the existing siding to level out irregularities before re siding with vinyl. It is called fanfold due to the fact that it is stored folded up like a handheld fan often used years ago which makes it easier to unfold when it is ready to be installed on a home.

When every penny counts you can rely on the performance of our most economical fanfold siding underlayment. This creates a horizontal seam every 4 feet. 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. It also serves as an air barrier.

It also helps with wind infiltration through the walls. 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. This reduces the likelihood of condensation within the wall cavity. Also it is a vapor barrior on boyh sides of the board.

By installing insulation on the outside of the framing it causes the location of the dew point to move to the outside of the wall assembly. Like bob said it helps with sound insulation. Products can be used on wood steel framing or concrete walls. If you have ever seen vinyl siding and the laps looked dirty all the time this is caused by heat buildup between the siding and the wall this heat excapes through the laps and causes stain.

It also helps to level the walls so you get a better smoother siding job. Generally referred to as rigid foam insulation this type of foam insulation is also called foam board foam plastic insulated. These products are also perforated to allow potentially harmful moisture vapor to escape so that it does not become trapped in the wall. The q series products have an extruded polystyrene foam xps core with high impact polystyrene capsheets on both sides which make it one of the most durable products currently available.

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. The products are easy to handle score cut and install and no special tools are needed.