ICE AND WATER BARRIER An ice and water barrier is required on all roofs except for detached accessory buildings (garages). The barrier may be at least two layers of underlayment cemented together or a self-adhering polymer modified bitumen sheet. There are several manufacturers who make materials specifically for this requirement that are marketed under differing trade names. The ice and water barrier must extend from the edge of the eaves to a point 24 inches inside the exterior wall line of the building. Ice and water barriers are required full-length in valleys (see picture on page 4 of this handout). The above noted ice and water protection requirements pertain to conditioned and unconditioned spaces. Ice and water protection is required on all attached garages.


EXCEPTION: Detached accessory structures that contain no conditioned floor area.

UNDERLAYMENT Underlayment shall be applied shingle fashion, parallel to and starting from the eave and lapped 2 inches (51mm), fastened sufficiently to hold in place. End laps shall be offset by 6 feet

VENTILATION Enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow. Any garage with an enclosed attic space shall be ventilated.