Minimum Roof Curb Height

Skylights can be successfully installed at steeper pitches but for flat roof applications the height at the top end of the curb will begin to be so great it will compromise aesthetics and potentially contravene planning permissions which in some cases will limit the height of any structure that can be built above roof level.

Minimum roof curb height.

12 300 mm o c. Top of all roof curbs shall be level with pitch built into curb when deck slopes. The only thing that helps is a very large intake to reduce velocity. 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.

Comply with local code requirements for minimum curb height but in no case shall curb height be less than 18 inches as measured from top of bar joist to top of curb nor shall curb height be less than 8 inches as measured from top of roof membrane to top of curb. Install compressible or tape to span. Internally insulated with 1 1 2 thick 3 lbs. The waterproof membrane flashing extends fully below the door frame bottom rail and is sealed to.

Roof curb shall be internally reinforced with angles 48 on center and factory installed wood nailer. A horizontal gap of minimum 10mm between frame front edge and drainage. The heater won t help much as it melt the snow and then the water will be drawn in. Roof deck install appropriate sealant behind membrane install compati ble sealant roof membrane tool to facilitate wate r e g polyurethane and run off 8 200 mm min.

The curb should provide a minimum clearance of 10 inches between the top of the finished roof surface and the top of the wood nailer continuous around the curb perimeter. The code often gives a minimum snow height for your area. Steeper pitches for skylight installation on flat roof. Roof mounted mechanical units shall be mounted on curbs raised a minimum of 8 inches 203 mm above the roof surface or where roofing materials extend beneath the unit on raised equipment supports providing a minimum clearance height in accordance with table 1509 7.

Imho this is not conservative enough and only protects from ground roof snow not from snow flakes in the air getting drawn in. If the curb does not include a counterflashing receiver. The waterproof membrane extends 150mm height in the door reveal and roof abutment wall. In no case should the curb be less than 14 inches in height.

Bottom flange top flange and drip.