Minimum Roof Insulation Thickness Ibc

If your community receives a lot of snow during the winter local building codes may require a minimum roof pitch for snow load which ensures that heavy snows will slide off.

Minimum roof insulation thickness ibc.

In some regions however local weather may dictate roof pitch. 2015 code requires walls to be insulated with a minimum of r 20 or r 13 5 13 5 means r 13 cavity insulation plus r 5 insulated sheathing. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. Astm b370 minimum 16 oz sq.

The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. Base flashing shall be of either corrosion resistant metal of minimum nominal 0 019 inch 0 5 mm thickness or mineral surfaced roll roofing weighing not less than 77 pounds per 100 square feet 4 kg m 2. Both codes provide specific instructions for re roofing projects and both are clear that replacements must comply with insulation r value requirements if the roof system is part of the building thermal envelope and contains insulation entirely above the deck. For pre formed metal shingle systems.

Continuous insulation zones ashrae 90 1 ashrae 189 1 igcc ibc iecc 2004 2007 2010 2013 2016 2009 2011 2014 2012 2015 2009 2012 2015 0 25 1 15 20 2 15 20 25 3 15 20 25 4 15 20 302535 5 15 20 302535 6 15 20 3035 7 15 20 3540 25 8 20 3540 25 minimum r value non residential above roof deck. Astm b209 0 024 inch minimum thickness for roll formed panels and 0 019 inch mini mum thickness for press formed shingles. Cap flashing shall be corrosion resistant metal of minimum nominal 0 019 inch 0 5 mm thickness. Base flashing shall be of either corrosion resistant metal of minimum nominal 0 019 inch 0 483 mm thickness or mineral surfaced roll roofing weighing not less than 77 pounds per 100 square feet 3 76 kg m 2.

If structural sheathing covers 40 or less of the exterior continuous insulation r value shall be permitted to be reduced by no more than r 3 in the locations where structural sheathing is used to maintain a consistent total sheathing thickness. High yield copper for metal sheet roof covering systems. Or component performance alternative of section c402 1 5 roof solar reflectance and thermal emittance fenestration in building envelope. Fasteners for asphalt shingles shall be galvanized stainless steel aluminum or copper roofing nails minimum 12 gage 0 105 inch 2 67 mm shank with a minimum 3 8 inch diameter 9 5 mm head of a length to penetrate through the roofing materials and a minimum of 3 4 inch 19 1 mm into the roof sheathing.

R value based method of section c402 1 3 u c and f factor based method of section c402 1 4. Specific insulation requirements of section c402 2 thermal requirements of either. Where the roof sheathing is less than 3 4 inch 19 1 mm thick the nails.