House Wrap Under Roof Sheathing

Plastic housewraps range from around 5 to over 50 perms.

House wrap under roof sheathing.

When water gets behind the siding house wrap is there to shed the water and keep it from entering the wall cavity. Its primary purpose is to prevent air and water leaks that may have seeped past the vinyl exterior. Traditional sheathing wraps such as asphalt felt and grade d building paper used under stucco both measure about 5 perms. Good option for all types.

Overlap horizontal seams 6 inches upper layer over lower layer. Can trap liquid water fdrom wall leaks. Most siding materials are not totally effective at repelling water particularly wind driven rain. Sheathing wrap under siding.

House wrap is a fabric paper or board material that covers the exterior sheathing of house walls to protect the wall framing. Overlap the layers shingle style as you go up the wall like roofing shingles. In general a sheathing wrap should have a perm rating of at least 5 to enable walls to dry out in a reasonable period of time should they get wet. Most have high permeability and high resistance to liquid water good air barrier if taped.

When tyvek is used under sheathing it functions only as an air barrier and does not protect the sheathing as a secondary weather barrier. In theory the sheathing on your home should never get wet as long as the proper preparations are made when siding the home flashing house wrap j channel caulk etc. In the end the decision to install house wrap under your siding is a personal one that you should make after discussing it with your contractor. Extend house wrap below the mudsill for water management but also for air sealing.

Where you ll often see plywood used instead of osb is in roof sheathing where the risks of moisture and leaks are greater. To sum it up house wrap is a lightweight paper like material that is most often used to completely cover the house directly on top of the sheathing and behind the vinyl siding. Low resistance to liquid water. Plastic housewrap not perforated.

Overlap vertical seams 6 12 inches. Tyvek has been used directly over studs where there is no sheathing although use of sheathing is a highly recommended building practice. Seal the bottom of the house wrap to the sheathing with caulk or tape.