The first sign is usually small. The paint on a window sill lets go, a siding board splits along a nail, or the edge of the deck gives a little underfoot. Most of the time, each one means water is getting in.
On older Peninsula houses that work comes sooner, and it’s the biggest kind of home improvement spending in the country. Americans spent about $81 billion on exterior replacements in 2023, about 20% of the total.
| Project | Spent in 2023 (billion dollars) |
|---|---|
| Roofing | 45.8 |
| Windows or doors | 22.1 |
| Porch, deck or patio | 16.0 |
| Siding | 9.4 |
| Chimney, stairs, other | 3.9 |
Source
In the source list: 1
A new roof goes to a licensed roofer we bring in, and our crew makes roof repairs. Most of the rest of that list is our own exterior upgrades work: siding, windows and doors, decks, waterproofing, trim and fascia, and rot repair.
Why older houses get there first
Half the homes in Palo Alto were built in 1963 or earlier, according to the Census Bureau. The median is 1966 in San Mateo County, 1976 in Santa Clara County and 1981 nationally.
| Area | Homes built before 1980 (%) |
|---|---|
| Palo Alto | 71.6% |
| San Mateo County | 71.1% |
| Santa Clara County | 58.0% |
| California | 54.8% |
| United States | 48.1% |
Sources (2)
Sources: US Census Bureau, American Community Survey 2024 1-year estimates, table B25034, Year Structure Built (shares are our math from the table’s counts) and table B25035, Median Year Structure Built.
Older homes cost more to keep up, and the numbers say by how much. Owners of homes built before 1940 spent about $6,700 on improvements and repairs in 2023, roughly 50% more than owners of homes built since 2010. Half of it went to replacements such as roofing, siding and windows.
Age brings one more rule. In a home built before 1978, federal lead rules apply once exterior work disturbs more than 20 square feet of paint, and window replacement is covered at any size. We’re an EPA Lead-Safe Certified Firm. Our lead paint guide explains what that means for you.
Look at the whole wall first
Water rarely stays where it got in. What gets past one part of the wall usually shows up in another, and the rot turns up somewhere other than the leak. So we start by looking at all of it.
- We assess the siding, windows, doors and deck together.
- If the job needs an engineer, we make the referral. We file the permits and handle the approvals.
- The old materials come off, and we repair rot as we find it in parts that carry no load.
- New siding and trim go on, then the waterproofing and the finish coats.
Rot or termite damage in anything load-bearing, deck framing included, goes to an appropriately licensed contractor. Our B-2 license covers the rest.
Choosing the siding and the windows
For siding we compare wood, engineered wood and Hardie fiber cement, on performance, cost and wildfire exposure. Hardie fiber cement carries a Class A fire rating per the manufacturer. Wood suits an older house where matching the original matters.
With windows, we check the energy performance and the flashing (the strips that shed water around the opening). Bad flashing is one of the most common ways water gets into a wall. If your original windows are worth keeping, read about wood sash and sill restoration before you replace them.
A wall at a window, in section
Illustrative section, not to scale
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We compare wood, engineered wood and Hardie fiber cement on performance, cost and wildfire exposure. New siding and trim go on, then the waterproofing and finish coats.
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Incorrect flashing is one of the most common ways water gets into a wall.
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Replacement and repair of exterior trim elements. One team handles siding, trim and finish work.
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For windows we look at energy performance and flashing. If the originals are worth keeping, restoring them is an option.
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Energy-efficient windows with proper flashing and weather sealing. Any exterior project that needs waterproofing gets it, including sealing around penetrations.
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We remove the old materials and repair rot in non-load-bearing members as we find it. Rot or termite damage in anything load-bearing goes to an appropriately licensed contractor.
Waterproofing goes under the finish
Every job that needs waterproofing gets it. On a deck, that means proper drainage and a membrane under the surface. The coating on top is the finish. The membrane is what keeps water out of the wood.
Our crew also does the exterior painting, and the same team takes the job through to the last coat.
Can you repair my deck instead of replacing it?
Often. We replace the rotted boards and trim, restore the surface and waterproof underneath. Problems in the framing go to a licensed contractor.
Will my project need a permit?
Many siding, window and door jobs do, and the rules vary by city. We check during the assessment and file what’s needed.
What should I fix first?
Whatever is letting the water in. Our guide to finding wood rot is worth a read before we visit.
If your siding, windows or deck are due, request an estimate or call us at (650) 961-7415.
Sources (3)
- Harvard Joint Center for Housing Studies, Improving America’s Housing 2025, Table A-1 and Figure 8 (from HUD’s 2023 American Housing Survey) jchs.harvard.edu (https://www.jchs.harvard.edu/sites/default/files/reports/files/Harvard_JCHS_Improving_Americas_Housing_2025.pdf) Back
- table B25034, Year Structure Built data.census.gov (https://data.census.gov/table/ACSDT1Y2024.B25034?g=160XX00US0655282,050XX00US06081,050XX00US06085,040XX00US06,010XX00US) Back
- table B25035, Median Year Structure Built data.census.gov (https://data.census.gov/table/ACSDT1Y2024.B25035?g=160XX00US0655282,050XX00US06081,050XX00US06085,040XX00US06,010XX00US) Back
