Insulation Over Existing Siding

Installing vinyl siding over wood siding wood must be sound.

Insulation over existing siding.

I ve always wondered if this compromised the r value of the wall assembly. Continuous insulation under new siding has become a popular way to improve energy efficiency on an existing home because it addresses a problem known as thermal bridging. Going over the existing siding adds to the r value by creating an air space between the insulation and old siding. Existing wood siding must be in good shape with no rot or mold and fastened tightly to the wall.

In other cases it must come off. Vinyl siding must be installed against a flat surface. Generally the best idea is to remove any existing siding from your exterior walls before installing the vinyl siding. 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.

This reduces the likelihood of condensation within the wall cavity. The exterior insulation also helps keep the siding all vinyl siding leaks further away from the exterior sheathing. Wrap the house with a moisture barrier usually some type of polystyrene wrap and install desired siding by nailing through the foam board into the house framing. Never never never let a contractor remove your old siding and install a tyvek material with insulation over the top.

Removing existing siding and installing osb has several benefits such as having brand new substrate on the home and the ability to inspect the wall cavity and all framing insulation and structural integrity of the home before replacing siding. If you do decide to cover your lap siding in vinyl you ll need to first layer the existing lap siding with highly durable foam insulation and a moisture prevention barrier. One major stipulation with the james hardie siding warranty is that it specifically states that if. Most homes in the united states are built with traditional wood frame construction with studs every 16 on center.

Keller sons llc roofing siding windows. Probably not significant but if you do insulate over the existing siding you have a separation between the insulation layer and the air barrier layer if there even is one. If the wood siding is beveled or lapped you. It also eliminates the problem of mold forming when insulation is attached directly to the substrate.