Installing Siding Over Foam Board

Strapping screwed or nailed to the framing through the foam will keep everything in place and provide a rain screen to help the siding stay dry.

Installing siding over foam board.

Installing the siding may be the easy part. Hardiplank lap siding can be installed over braced wood or steel studs spaced a maximum of 24 o c. Use nails long enough to. Use foam board rated for exterior use that is mold and mildew resistant as well as waterproof.

But the use of exterior foam on the outside of the building raises other concerns namely how to prevent the accumulation of water in the wall that would encourage mold and rot. 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. Measure and cut the foam board to match the exterior wall that needs to be covered. When using foam insulation you ll need to decide whether you intend to use osb in addition to the rigid foam to serve as the building sheathing or if the rigid foam layer will itself serve as the sheathing and you ll need to determine what will serve as the drainage plane and where this layer will be.

Installing rigid foam sheathing. Instantly access installation info technical bulletins sds sheets more. Trying to install siding over existing siding along with plastic sheeting requires a level surface. Hardiplank lap siding can also be installed over foam insulation up to 1 thick irregularities in framing sheathing and or foam insulation can mirror through the finished application.

In locations with high exposure to wind driven rain it may be necessary to install tar paper or housewrap behind foam sheathing to help control any rainwater that penetrates the siding. This detail is used with both new construction and also with renovation work. We show z flashing below the first course of siding and we show perforated board wrapped with insect screening to allow air entry at the base of the wall. Below are some of the design details along with the benefits.

Siding over rigid foam. Or directly to minimum 7 16 thick osb sheathing.