Roof Insulation Ventilation Gap

Seal any roof vents into the parts of the attic that are not heated.

Roof insulation ventilation gap. If the roof covering or roof membrane is a material of high moisture resistance or impermeable then the building regulations require a 50mm wide ventilation gap beneath the roofing felt and tiles. Though it s against building code to vent any kind of exhaust to an attic space many home builders have gotten away with this shortcut. Condensation encourages rot and mould growth. Leave a clear space between the top of the insulation and the underside of the roof sheathing to allow for roof ventilation.

Installation of this type of attic ventilation involves leaving a gap in the sheathing along the ridge and covering it with a perforated vent. Where a warm roof is required it is usually possible to install all the insulation required within the depth of the rafters while leaving a clear ventilation gap of at least 50mm below their upper edge. Use hardware cloth metal flashing or scrap plywood to create a safety gap of at least 3 inches all around fixtures. Roofing shingles and materials plus factory certified roofers including ratings from real homeowners from north america s largest roofing manufacturer.

If you choose to vent the roof deck then be serious about it and really vent it. The air gap dimensions shown on the drawings are the minimum widths required for clear continuous ventilation air paths at the eaves. Staple a continuous polyethylene air and vapour barrier to the rafters and end wall studs. This is typical practice when an old fashioned black sarking felt is in place and commonly found in existing buildings.

Roof voids must be ventilated in order to stop warm air condensing on cold surfaces. However for rafters of less than 200mm dormer roofs for example it may be necessary to fix insulation boards to the lower face of the rafters. Residential and commercial roofing shingles slate roof ventilation roof underlayments asphaltic and tpo roof membranes. Static vents often protrude from roofline thanks to.

Of airspace between the top of the insulation and the back of the roof sheathing. Then carefully seal the edges and seams with acoustical sealant. The code calls for a minimum of 1 in. Duo pitch roofs greater than 200 pitch or greater than 10m span should have additional ventilation at the ridge to assist airflow through the roof void equivalent to at least a 3 mm wide continuous gap.