Apartment Building Roof Replacement In Los Angeles, CA

This two-story apartment building sits on a hillside street in Los Angeles. The apartment building roof replacement in Los Angeles covered two kinds of roof. The sloped sections got gray Owens Corning cool roof shingles. The one flat section got a white cap sheet. Below, we show how each part was built and what the Los Angeles cool roof rule means for a building like this.

What Did This Apartment Building Roof Replacement In Los Angeles Include?

Two roof systems on one building. Most of the roof is sloped, with hips, gable ends, skylights and a lot of pipe vents. One section is flat, and shingles can't go on a flat roof. So each part got the system that fits it.

On the sloped sections, here's the order we worked in:

1. Waterproof layer. With the old roof off, we covered the wood with a synthetic underlayment (Owens Corning Titanium UDL50). Owens Corning rates it as up to 2.5 times stronger than other premium underlayments.
2. New pipe flashings. Every pipe vent got a new flashing, the metal collar that seals around it. Old flashings are one of the most common leak spots on apartment roofs.
3. Shingles, section by section. Bundles were staged across the roof and laid in order, one section at a time.
4. Hips and ridges. Every outside corner got its own row of cap shingles last.

Why Cool Roof Shingles On An Apartment Building?

Because Los Angeles requires them on most roof replacements. Title 24 (California's energy code) sets the statewide cool roof requirement, and Los Angeles adds its own. Under the city's green building code, a sloped roof on a low-rise residential building needs a cool roof score (SRI) of at least 20. The rule kicks in when more than half of the roof is replaced, which is any full re-roof.

The shingles on this building are Owens Corning Duration COOL. Owens Corning makes this line for California's cool roof rules, with each color rated by the Cool Roof Rating Council. The color is a gray blend that suits the building's Spanish-style stucco and arched windows.

There's a practical reason too. On an apartment building, the people under the roof are top-floor tenants. A roof that reflects the sun keeps those units cooler in summer. Want to see the coolest color in the line? See our Shasta White cool roof in Northridge.

How We Built The Flat Section

A flat roof needs sheets that seal together, not shingles. We built this one up in layers, the same way we build every flat roof:

1. Base sheet. The first layer is nailed to the wood with wide-cap nails.
2. Smooth torch-down layer. A smooth sheet is heated with a torch so it melts onto the base sheet. This is the first fully waterproof layer.
3. White cap sheet. The top layer is a white Polyglass cap sheet, torched over everything and sealed around each pipe.

Why white? The same Los Angeles rule sets a much higher cool roof score for flat roofs. That's why flat sections are almost always white or light gray. On an Encino home we used the same layered method to build a flat roof ready for solar panels.

What The Finished Roof Looks Like

The video below is a walk across the finished sloped sections. Every hip is capped, and every pipe vent and skylight is sealed into the new shingles. At the edge, the white flat section ties into the shingles.

What Is Different About Re-Roofing An Occupied Apartment Building?

Three things: more roof sections, more pipes and skylights poking through, and people living under it the whole time. This building has several skylights and a lot of pipe vents. Each one is a place water can get in if it's sealed badly, so the flashings were replaced, not reused. A multifamily roof replacement also has to keep moving, because every open section is over someone's home.

Working in sections matters too. In the second video you can see finished shingles next to a section still in its waterproof layer. The roof was done one section at a time, so no part of the building sat open for long.

If you own an apartment building and are planning a re-roof, a few things make the job go smoothly:

• Tell your tenants the dates. Roofing is loud during the day. A week's notice goes a long way.
• Keep the driveway or a parking spot clear. Material deliveries and the debris trailer need a place to go.
• Ask about the permit. The City of Los Angeles requires a permit for a re-roof, and the contractor signs a re-roofing certificate at the end. We pull the permit on every re-roof.

Rules can change, so check with LADBS, the city's building department, or ask us during your estimate.

Own An Apartment Building That Needs A New Roof?

We replace apartment building roofs across the San Fernando Valley, including the City of Los Angeles and nearby cities like Glendale and Burbank. Our commercial roofing team handles apartment buildings up to four stories, with shingle, flat and cool roof systems. We're a licensed roofing contractor (CSLB C-39 #910673) with our own crews, and we pull the permit on every re-roof. Book a free estimate and we'll walk the roof with you.