DIY Network

Roofing and Flashing From "Healthy Household Workshop" episode DHHW-102

A bad roof can be a mold generator: an inadequate slope and flashing, along with clogged gutters and downspouts invite mold into your home.

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	Sheathing, topped by underlayment
	Flashing
	Guttering

Proper roofing and flashing techniques:

• All homes should have a tight roof construction, with sheathing of 1/2" plywood or OSB. Proper sheathing ties the rafters together and supports shingles. When improperly installed, sheathing can buckle and cause larger holes around the nails and result in leaks.

• A good underlayment (usually 15- or 30-lb. felt) between the roofing shingles and the sheathing, is essential.

• Flashing seals areas of transition or penetration (where architectural features, exterior electrical features or plumbing or the roof and walls meet).

• Venting: 1 square foot per 150 square feet of attic floor. Half the vents should be at the eaves and half at the ridge.

• Guttering can keep the moisture away from the sheathing.

• Removal of overhanging tree branches to dry out roof mold.