Roofing H USA re-roofs homes across Los Angeles, where the City’s Green Building Code asks for cool roofing material and then lists five situations it leaves out.
Those exceptions matter because the City’s rule is not the state rule. It has its own values, its own list and no climate zone condition, so an exception written into the state energy code does not always carry over.
Which re-roofs does the Los Angeles cool roof rule leave out?
The rule sits in the City’s Green Building Code, in one version for residential buildings and a matching one for nonresidential buildings. Both carry the same five exceptions:
- A roof repair, as the California Energy Code defines repair.
- A roof replacement of no more than half of the total roof area.
- A roof replacement where solar systems are being installed.
- An addition with less than 500 square feet of added roof area, or less than half of the total roof area, whichever is greater.
- Roof construction with heavy thermal mass over the roof membrane, vegetated green roofs included, above a weight per square foot set in the code.
Anything outside that list has to meet the City’s minimums for aged solar reflectance plus thermal emittance, or its Solar Reflectance Index instead. The required values change with roof slope and with building height.
What counts as a roof repair under that rule?
The City does not define repair itself. It points to the California Energy Code, which calls a repair the reconstruction or renewal of a part of an existing building for the purpose of maintenance.
The same definition sets two limits. A repair cannot raise the energy use of the part that is repaired, and replacing a component that has requirements in the energy standards counts as an alteration, not a repair.
Roofing products do have requirements there, reflectance and emittance among them. Resealing a flashing to stop a leak fits the idea of maintenance; tearing off and replacing the roofing over an area sits closer to the alteration side.
If your job is near that line, ask LADBS, the City’s building department, how it reads your scope. The answer decides whether the half-the-roof exception below is the one that matters.
How is the half-the-roof line measured?
The exception compares two areas: the roof area being replaced and the total roof area. When the replaced part is half of the total or less, the City’s rule does not reach that job.
Past that point it does. LADBS’s express re-roof lines say the same for homes: once a residential replacement goes beyond half of the roof, they call for a Cool Roof Rating Council labeled product.
Those express lines also leave a blank for the number of squares, so the replaced area is on paper from the moment the permit is issued. Ask the quote to show both figures, the replaced area and the whole roof.
Additions are measured by the new roof area they create. An addition with less than 500 square feet of new roof stays outside the rule, and on a large house the limit rises to half of the total roof area.
Does adding solar or a green roof change the answer?
Yes, in two of the five exceptions. A roof replacement where solar systems are being installed is left out of the City’s rule, and so is roof construction with heavy thermal mass over the membrane, such as a vegetated roof.
The state energy code handles solar more narrowly. It exempts only the roof area covered by building-integrated photovoltaic or solar thermal panels from its reflectance values.
Solar also brings its own paperwork. LADBS can issue some rooftop photovoltaic systems on houses as express permits online, under a list of conditions, and it notes that the structural support for the panels may need a separate building permit.
If solar is part of your plan, say so before the roof replacement quote is written, so the roofing, the panels and the cool roof question are handled together.
Do tile resets, historic homes or attic insulation count as exceptions?
A tile reset is handled outside the list. On a tile roof, the LADBS express line for lifting the tiles, applying new underlayment and resetting them states that cool roof compliance is not required.
Historic status is not an exception. LADBS says the approval process for cool roofs on historic buildings and in historic zones is the same as for any other roof.
Attic insulation is the easy one to misread. The state energy code accepts enough ceiling insulation, an attic radiant barrier or continuous insulation at the deck in place of a cool roof on steep-sloped home roofs. The City’s five exceptions do not mention those options.
Climate zone is similar. The City takes in Climate Zones 6, 8 and 9, and the state’s steep-slope rule skips Climate Zone 6, yet the City’s tables set values by slope and building height alone. Check with LADBS before counting on a state exception.
Talk to us
Wondering whether your re-roof fits one of the five exceptions? Reach Roofing H USA on (213) 921-3424, describe the size of the job and the roofing you have, and we will check it against the City’s list with you.