Installing Siding Over Foam Board

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.

Installing siding over foam board.

Instantly access installation info technical bulletins sds sheets more. This detail is used with both new construction and also with renovation work. Measure and cut the foam board to match the exterior wall that needs to be covered. Installing rigid foam sheathing.

Place the foam board over the wall and screw in place. 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. 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. Or directly to minimum 7 16 thick osb sheathing.

Hardiplank lap siding can be installed over braced wood or steel studs spaced a maximum of 24 o c. Installing the siding may be the easy part. Installing foam board insulation under vinyl siding today more than ever before homes are being built with foam board insulation installed on the outside of the sheathing and under the siding. 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.

Use foam board rated for exterior use that is mold and mildew resistant as well as waterproof. 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. Trying to install siding over existing siding along with plastic sheeting requires a level surface. To sum up if you want to install tar paper or a housewrap with foam sheathing install it under the foam sheathing but keep the air space between the siding and foam.

Siding over rigid foam. 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.