You can add r0 5 again if the fanfold makes airgaps over clapboards below.
Fanfold insulation under vinyl 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.
A corresponding editor paul fisette responds.
It also serves as an air barrier.
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.
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 products are easy to handle score cut and install and no special tools are needed.
Is the fan fold foam an adequate weather resistive barrier.
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.
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.
It also reduces heat bridges through the 2x4 studding.
The combination of those 4 effects can sometimes cause an unexpectedly big gain in efficiency.
Rigid foam will shed any water that gets past leaky vinyl siding.
To be an effective weather resistive barrier though the seams of the fan fold must be carefully taped since any seam can provide a pathway for water to reach the structure under the foam.
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.
Before installing vinyl siding over existing wood siding we first install a layer of fan fold foam insulation.
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.
Offers tough poly facers for added strength and durability important in storing handling and installation.
Fanfold when every penny counts you can rely on the performance of our most economical fanfold siding underlayment.
Home accessories 3 8 fanfold insulation sheathing underlayment 3 8 fanfold insulation sheathing underlayment cellofoam s poly shield heat laminated sheathing.
