Our Certifications & Accreditations
Thornton Colorado Roofing Codes
Denver roofing contractors reference the Thornton Colorado Roofing Codes for residential roof repair and replacement and commercial roof repair and replacement. The building code and energy codes are based on 2015 specifications.
Information Updated On
11/27/18
Building Department Phone
303-538-7250
Inspection Line
303-538-7396
Fax
303-538-7650
Current Building Code
2015 IBC/IRC
Current Energy Code
2015 IECC
Requires a Building Permit
Yes
Roof System/Fire Rating required for Residential Dwellings
Class A
Roof System/Fire Rating required for Commercial Buildings
Class A
Roof System/Fire Rating required for Multi-Family
Class A
Special conditions
Roof class is dependent on construction type
Minimum sustained wind speed rating for Asphalt Shingles
90 mph 3 second gusts
ASTM Standard for wind rating
ASTM 3161
Requires a manufacturer’s wind warranty
Yes
Requires wind nailing
Yes
Inspectors carry ladders for the final
No
Requires midroof (in progress) inspection
Yes
Maximum number of layers of flat roof material permitted
2 if allowed by manufacturer
Require a sheathing/decking inspection
Yes when any portion of decking replaced
Requires solid sheeting (plywood/OSB) over spaced decking
Yes
Maximum gap size for sheeting
¼ inch gap
Requires drip edge
Yes
Drip edge size minimum
1×2 minimum ¼” below sheathing
Requires Rake/Gable metal edging
Yes
Enforces the use of Self Adhering Underlayment (i.e., Ice & Water)
No
Underlayment required for 4:12 and above
15#
Type of valleys allowed
Both
Valley Underlayment/Material required for closed valleys
Either – in accordance with installation instructions
Valley Underlayment/Material required for open valleys
Ice and water under metal
Kick-out required on Step Flashing
Yes
Minimum curb height requirement
No
Requires ridge cap
Yes
Requires ventilation to meet building codes
Yes
Permits Soffit eave/vents
Yes, new construction only
Allows 90 lb rolled roofing on low slope heating living space
Yes
Low Slope
1:12