Longmont Colorado Roofing Codes

Here are the Longmont Colorado roofing codes. Note there will be changes in the roofing codes at the end of 2018. A double layer of underlayment is required on roof replacements in Longmont.

Information Updated On

8/22/18

Building Department Phone

303-651-8332

Inspection Line

303-651-8332

Fax Line

303-651-8332

Department Website

Current Building Code

2015 IBC

Intends to Update Code in the Future

Yes, late 2018

Current Energy Code

2015 IECC

Requires a Building Permit

Yes

Minimum sustained wind speed rating for Asphalt Shingles

110 MPH sustained wind/130 MPH 3 second gusts

ASTM Standard for wind rating

ASTM D3161 Class F, D7158 Class G & H

Requires a manufacturer’s wind warranty

Yes

Inspectors carry ladders for the final

Yes, with one story access

Requires midroof (in progress) inspection

Yes, for commercial before dry-in

Maximum number of layers of asphalt shingles permitted

Only 1 layer is permitted

Maximum number of layers of flat roof material permitted

Only 1 layer permitted

Requires solid sheeting (plywood/OSB) over spaced decking

Yes

Requires drip edge

Yes

Drip edge size minimum

2 x 3

Requires Rake/Gable metal edging

No

Enforces the use of Self Adhering Underlayment (i.e., Ice & Water)

No

Underlayment required 2:12 up to 4:12

A double layer of underlayment required

Underlayment required for 4:12 and above

One layer of minimum Type 15 required

Type of valleys allowed

Both

Valley Underlayment/Material required for closed valleys

Either

Valley Underlayment/Material required for open valleys

Either

Kick-out required on Step Flashing

Yes

Requires ventilation to meet building codes

Yes

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