These products are also perforated to allow potentially harmful moisture vapor to escape so that it does not become trapped in the wall.
Fanfold insulation for vinyl siding.
Also it is a vapor barrior on boyh sides of the board.
Fanfold board is worth the cost and effort to install behind vinyl siding.
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.
The products are easy to handle score cut and install and no special tools are needed.
Foamular extruded polystyrene xps rigid foam insulation offers a comprehensive line of products in a wide choice of sizes thicknesses and edges with a lifetime limited warranty for the life of the home or building.
This reduces the likelihood of condensation within the wall cavity.
Like bob said it helps with sound insulation.
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.
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 with wind infiltration through the walls.
I have not seen any studies that show how well tape adheres to foam over the long haul.
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.
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.
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.
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.
This creates a horizontal seam every 4 feet.
It also helps to level the walls so you get a better smoother siding job.
The exterior insulation also helps keep the siding all vinyl siding leaks further away from the exterior sheathing.
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.
Exterior fanfold insulation is the foam type of insulation that is applied between your home s exterior and the siding and it offers some protection from moisture in addition to creating a layer of thermal insulation.
It also serves as an air barrier.
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.
