The median home in LA County was built in 1965, and in the City of Los Angeles also in 1965. A reroof on such a house is a whole-home scope: the covering, the layers beneath, the sheathing and the details at every edge.
What a tear-off finds
The first surprise is usually layers. A house may carry two or three coverings. In County jurisdiction, a covering may only go over one existing layer, and beyond that limit everything comes off.
The second is the deck. Old sheathing can be stained, split, soft at the eaves or too thin to hold nails. The assessment cannot see all of it from above, so the scope should include an allowance for deck repair and a stated rate for extra sheathing found.
The third is the edge detail. Old flashing, missing drip edge and rusted vents are replaced as part of the job, since a new covering over old details leaks at the details.
Chimneys and old rooftop penetrations deserve a closer look. Unused vents and flues can be capped or removed. Brick chimneys on older houses need flashing that works with the masonry, not only sealant.
Spaced sheathing and plywood
Many older houses have sheathing laid as spaced boards with gaps between them, a pattern made for wood shakes that needed air under them. New asphalt, tile and metal coverings need a solid deck.
The usual fix is closing the gaps with plywood over the old boards, or replacing them. That gives the nails something to hold and the underlayment something to lie on. It also affects the radiant barrier exception in the Energy Code, which does not apply over spaced sheathing.
A deck that is sound and dry is a condition of reroofing over an existing layer in LA County jurisdiction. Spaced boards fail that test for most modern coverings.
Where an older house has a deck of solid boards, the same standard holds: dry, sound and solid. Replace any board that holds a nail poorly.
What an older-house scope should name
- Number of existing layers and who removes them
- Deck allowance and the rate for extra sheathing
- Closing spaced boards with plywood
- Testing of older materials, sampling and disposal
- Flashing, drip edge and vent replacement
- Building department check, where it applies
Signs an older roof needs a whole-home scope
- More than one covering visible at the edges
- Sagging or soft areas between rafters
- Daylight visible in the attic
- An insurer asking for roof age or condition
Photo by Olga Zakharchenko on Unsplash
Testing before tear-off
Older roofs can contain materials that must be tested before removal, so ask your roofer.
Before tear-off on an older house, ask whether testing has been done and who takes the sample. Your building department can say what notice rules apply to your address.
Insurance
Insurance can press on an older roof. Writing on 26 May 2026, Insurance Business America said Mercury and Wawanesa will not usually cover a house with a roof older than 25 years, tile and slate excepted, and that Farmers may pay only actual cash value on an asphalt roof past 15 years, and the FAIR Plan withholds full replacement cost when a roof past 25 years has not been replaced.
United Policyholders reported, on 3 May 2025, insurers mailing re-underwriting letters that told owners to replace the roof, citing worn shingles and lost granules. Read your own policy and letters.
Older house questions
What does a tear-off find on an older house?
Extra layers, stained or soft sheathing and worn flashing and vents. In County jurisdiction, a covering may only go over one existing layer, so beyond that everything comes off. Ask for a deck allowance and a stated rate for extra sheathing in the scope.
Why close spaced sheathing with plywood?
Spaced boards were made for wood shakes. Asphalt, tile and metal need a solid deck for nails and underlayment to hold. Plywood over the gaps, or new sheathing, provides it.
Does old roofing need testing before tear-off?
Ask whether testing has been done, who takes the sample and who handles disposal. Your building department and the regional air district can say what notice rules apply.
What should an older-house scope name?
The number of existing layers and who removes them, a deck allowance with a stated rate for extra sheathing, and the flashing, drip edge and vent replacement.
How does roof age affect insurance on an older house?
Age can limit what a policy pays. Per an Insurance Business America report of 26 May 2026, Farmers may pay only actual cash value on an asphalt roof past 15 years, and the FAIR Plan withholds full replacement cost when a roof past 25 years has not been replaced.