---
title: "Flat Roof Repair and Torch-Down Roofing in Los Angeles"
description: "Flat roof repair in Los Angeles: torch-down, modified bitumen and coating repairs or a full flat roof replacement, by a licensed roofer (CSLB #1147688)."
url: "https://aacaliforniaroofing.com/flat-roof-services/"
updated: "2026-10-20"
---

# Flat Roof Repair and Torch-Down Roofing in Los Angeles

AA California Roofing does flat roof repair in Los Angeles: we fix ponding, blistered or split torch-down and modified-bitumen membranes and failed seams, and we install new torch-down systems when the old roof is done. We work on flat and low-slope roofs on homes, additions and commercial buildings. CSLB license #1147688; estimates are free.

Book a flat roof inspection through our [contact page](https://aacaliforniaroofing.com/contact-us/); we are open Sunday to Friday, 8 AM to 8 PM. We cover all of Los Angeles County, from the San Fernando Valley to the coast, plus Simi Valley, Thousand Oaks, Moorpark, Camarillo and Oxnard.

A "flat" roof is never truly flat. The Energy Code calls it low-sloped: a pitch under 2:12, meaning less than 2 inches of rise per foot of run. That shallow slope is why these roofs use continuous membranes instead of overlapping shingles or tiles, and why they fail in different ways.

## Why flat roofs leak in Los Angeles

- **Ponding.** Water that sits after rain finds every weak seam, and the wet-dry cycle ages the surface faster. Ponding usually points to a sagging deck, a low spot or a clogged drain or scupper.
- **Sun and heat.** Long, dry, sunny months wear the surface down: cap-sheet granules come loose, coatings chalk, and the asphalt underneath cracks into an "alligator" pattern.
- **Seams and laps.** Membranes are laid in overlapping sheets. A lap that was under-heated during installation, or that has been stressed by movement, opens up.
- **Parapet walls.** The flashing where the roof turns up the wall, and the cap on top of the wall, are common entry points. Water can also enter through the wall itself and show up as a roof leak.
- **Penetrations and equipment.** AC units, vents, skylights and their curbs each break the membrane and need their own flashing, and technicians walking to the equipment wear paths into the surface.
- **Blisters.** Moisture or air trapped under the membrane expands in the heat and lifts a bubble that can split open.

## Torch-down, TPO or a roof coating: which suits a flat roof in Los Angeles?

On a Los Angeles house, the usual flat roof choices are a torch-down modified bitumen membrane, a single-ply membrane such as TPO, or a coating over the roof that is already there. Torch-down and TPO are complete roof systems. A coating only renews the surface, and only when the membrane under it is still dry and well bonded. Which one fits depends on what is under the surface, how the roof drains and the cool-roof rules for your ZIP code.

We repair and install torch-down and modified bitumen roofs, and we recoat roofs that pass that dry-and-bonded check. If your roof is TPO now, or a bid you hold proposes it, tell us when you book and we will say whether it is work we take on.

The California Residential Code gives each flat roof covering its own section: built-up roofing (two or more layers of felt cemented together and surfaced with a cap sheet, gravel or a coating), modified bitumen (polymer-modified asphalt sheets; torch-down is the torched kind), single-ply membranes such as TPO, PVC and EPDM, spray foam, and liquid-applied roofing. Roof coatings have a section of their own.

| On a Los Angeles flat roof | Torch-down (modified bitumen) | TPO (single-ply) | Roof coating |
| --- | --- | --- | --- |
| What it is | Polymer-modified asphalt sheets, usually a base sheet under a granulated cap sheet | One layer of reinforced thermoplastic polyolefin sheet | A liquid (acrylic, silicone, polyurethane or asphalt-based) over the existing roof. It renews a roof; it is not a new one |
| How it is installed | Each sheet is heated with a propane torch and fused down. The fire code treats this as hot work: a fire watch during the work and for at least 30 minutes after it ends (California Fire Code 3504.2.1) | Fastened or adhered to the deck, with the seams welded by hot air. No open flame | Rolled or sprayed on. No flame and no tear-off |
| A new layer without a tear-off? | Only where the manufacturer's instructions allow it, the old roof is dry and sound, and it has fewer than two coverings already (CRC R908.4). Otherwise a tear-off | The same rule as torch-down | Allowed over existing modified bitumen, built-up or single-ply roofing without a tear-off, but never over a roof that is water-soaked or too worn to be a base |
| Reflective surface (climate zones 4 and 6 to 15) | The cap sheet, or a coating over it, must reach an aged solar reflectance of 0.63 with a thermal emittance of 0.75, or an SRI of 75, on its CRRC rating; extra deck insulation can take its place | Sold in white and other colors; the exact product's aged CRRC rating has to meet the values | The Energy Code's re-roof rule includes "adding a new surface layer", so a coating over more than half the roof should be a CRRC-rated reflective product |
| R-14 insulation on a replacement in zone 9 (Woodland Hills, Van Nuys, Pasadena); none in zone 6 (Santa Monica, Torrance, Long Beach) | Required unless an exception applies, so flashings, drains and curbs may have to be raised to suit | Required too, unless an exception applies: a white surface answers the reflectance rule, not the insulation rule | On its face, the code's wording also reaches a coating over more than half the roof. Ask how the permit office applies it before choosing a coating to skip the insulation |
| Standard to ask for on the bid | ASTM D6162, D6163, D6164, D6222, D6223 or D6298 (CRC Table R905.11.2) | ASTM D6878 (CRC Table R905.12) | Acrylic ASTM D6083, silicone D6694, moisture-cured polyurethane D6947, or an asphalt coating standard (CRC Table R909.2) |
| With AA California Roofing | We repair and install it | Ask us first whether we take the job on | We recoat roofs that pass the dry-and-bonded check |

### Can a coating stand in for a new flat roof?

Only on a roof that is still sound enough to be a base for new roofing. A coating does not dry wet insulation or firm up a soft deck; spread over them, it seals the water in, out of sight. Section R908.4 of the 2025 California Residential Code allows a coating over an existing roof without a tear-off, but no recover over a roof that is water-soaked or too deteriorated to be an adequate base. A recoat bid should say how the roof was checked for wet areas; how we check is in the next section.

### How many years should a flat roof last?

No reliable number of years fits every flat roof; for the product on yours, its manufacturer's documentation is the reference. Material warranties are provided directly by the manufacturer and are subject to the manufacturer's terms. Read the years on any warranty with care: the National Roofing Contractors Association advises that a [warranty's length](https://nrcawebstorage.blob.core.windows.net/files/nrca_website/documents/technical/consumer-advisory-bulletin-issue-1-Roof-System-Warranties.pdf) should not be the main reason to choose a roof system, because it does not assure performance, and that some warranty terms were set without research or field records of how the roof holds up.

Before you choose, check which surface and insulation your address needs: our guide to the [cool roof rules for flat roofs](https://aacaliforniaroofing.com/cool-roof-requirements-los-angeles/) has the CRRC values and the City of Los Angeles rule for homes, which sets higher values than the state's. Offices, shops and apartment buildings are covered on our [commercial roofing page](https://aacaliforniaroofing.com/commercial-roofing/).

## Repair, recoat, re-cover or replace: how we decide

The decision depends on what is under the surface, not only on what shows on top. Wet insulation and soft decking cannot be seen from the roof, so we check suspect areas by feel and by opening small test spots, and look at the deck from below where it is exposed.

| What we find | Usual answer | Why |
| --- | --- | --- |
| One split seam, a blister or a flashing failure; the rest of the membrane is sound | Repair | The roof has life left; fixing the one failure is enough |
| The surface is worn, but the membrane is dry and well bonded | Recoat with an approved roof coating | Restores UV protection and can add reflectance; LADBS lists coating an existing roof as an express permit |
| The old roof is dry, flat and well attached, with no wet insulation, and the building code allows another layer | Re-cover (a new membrane over the old) | Avoids a full tear-off; the Energy Code still counts a new layer as a roof replacement |
| Wet insulation, a soft deck, repeated leaks, or layers already stacked up | Tear-off and replace | A new layer over trapped moisture rots the deck from below and fails early |

## Torch-down roofing explained

Torch-down is modified-bitumen roofing: asphalt blended with polymers, reinforced with a mat and made in rolls. The installer heats the underside of each roll with a propane torch until the asphalt melts, then rolls it out so it fuses to the layer below and to the edge of the neighboring sheet.

### How a torch-down roof is installed

1. The old roofing comes off (or is prepared for a re-cover), the deck is repaired, and drains and scuppers are checked.
2. Insulation board goes down where the code calls for it, followed by a base sheet fastened or adhered to the deck.
3. The cap sheet is torched over the base, with its laps offset from the base laps and sealed.
4. The membrane is turned up parapets and around curbs, pipes and drains as flashing.
5. The finished surface is a granulated or coated cap for UV protection, or a reflective cap or coating where the cool roof rules require one.

### Strengths and trade-offs

The strengths are fused seams instead of glued ones, a tough surface that handles some foot traffic around rooftop equipment, and repairs that use the same torch-and-patch method. The trade-offs are the open flame, which calls for a careful crew and a fire watch near wood and parapets, and the heat a dark granulated cap absorbs unless it is a cool-rated product. How long the roof lasts depends mostly on drainage, sun exposure and upkeep; standing water shortens it more than anything else.

## Cool roof and insulation rules for flat roofs in California

When more than 50 percent of a home's low-slope roof is replaced (a new layer over the old one counts), Section 150.2(b)1I of California's 2025 Energy Code sets two requirements. They cover permits applied for since January 1, 2026.

- **A reflective surface, in climate zones 4 and 6 to 15.** The roofing product must reach an aged solar reflectance of 0.63 or more and a thermal emittance of 0.75 or more, or a Solar Reflectance Index of 75 or more. Added roof-deck insulation can replace some or all of that (Table 150.2-E): in zones 6 and 7, R-10 continuous insulation removes the reflectance requirement; in zones 2, 4 and 8 to 15 it takes R-24.
- **Roof insulation, in zones 1, 2, 4 and 8 to 16.** The roof needs R-14 continuous insulation, or an assembly U-factor of 0.039 (Table 150.2-F). Exceptions cover roofs that already have R-10 continuous insulation, roofs with R-19 between the rafters in contact with the deck in zones 1, 2, 4 and 8 to 10, and a reduced R-4 where rooftop equipment or parapet walls would leave too little flashing height.

What that means by address, using the Energy Commission's ZIP code list: a flat roof in Woodland Hills, Encino, Van Nuys, North Hollywood or Pasadena (zone 9) needs both a reflective cap or coating and R-14 insulation, unless an exception applies. A flat roof in Santa Monica, Torrance or Long Beach (zone 6) needs the reflective surface, but not the insulation. Apartment and commercial buildings follow their own sections of the code. Our [cool roof requirements guide](https://aacaliforniaroofing.com/cool-roof-requirements-los-angeles/) explains the rules in more detail.

## What drives flat roof repair cost

We price flat roof work after the inspection, because the same roof size can mean a one-seam repair or a full tear-off. These are the items that move the price, and the ones to compare when you read two bids:

- **Repair, recoat, re-cover or replace.** The table above is the biggest single factor.
- **Wet insulation and deck damage.** Saturated insulation board and soft decking have to come out; the amount is only known once the roof is opened.
- **Code insulation on a replacement.** In zones 8 to 16, adding R-14 continuous insulation is part of the job unless an exception applies, and it can also mean raising flashings, drains and curbs.
- **Parapets, drains and equipment.** Each parapet run, drain, scupper and equipment curb needs its own flashing; lifting and resetting rooftop units adds a trade.
- **Access.** A single-story garage roof is simpler than a three-story apartment roof that needs material hoisted up.

## Flat roofs on homes, additions and commercial buildings

- **Homes and additions.** Low-slope sections sit over room additions, garages and covered patios, and some homes are flat-roofed throughout. The weak spot is where a flat section meets a pitched roof or a wall; that transition needs its own flashing and is a frequent leak source.
- **Apartment buildings.** Roofs carry AC units, vents and often solar panels, and repairs are scheduled around tenants and access.
- **Commercial buildings.** Larger areas, parapets, interior drains and rooftop equipment. Nonresidential re-roofs follow Section 141.0 of the Energy Code, and the LADBS express permit bulletin notes that a cool roof may be required for them. Our [commercial roofing page](https://aacaliforniaroofing.com/commercial-roofing/) covers these buildings.

## Keeping a flat roof working

- Clear drains, scuppers and gutters before the rainy season and after windstorms.
- After a rain, look for water still standing once the rest of the roof has dried. Note the spot and tell us.
- Check parapet caps and the flashing at walls for cracks.
- Keep foot traffic to paths around equipment, and ask service technicians not to set tools down on the membrane.
- Recoat when the surface chalks or the granules thin, before the membrane itself starts to crack.

## Book a flat roof inspection

Send photos of the problem area to [aacaliforniaroofing@gmail.com](mailto:aacaliforniaroofing@gmail.com), or request a visit on our [contact page](https://aacaliforniaroofing.com/contact-us/). The estimate is free. For leaks on pitched shingle or tile sections, see our [roof repair service](https://aacaliforniaroofing.com/roof-repairs/); for a whole-house re-roof that includes pitched and flat sections, see [roof replacement](https://aacaliforniaroofing.com/new-roof-installation/). Everything else we do is on the [AA California Roofing home page](https://aacaliforniaroofing.com/).