Hardwood Flooring in Palo Alto

Palo Alto Conditions That Affect Solid Hardwood

Derived statistic, not a published normal: averaging NOAA Local Climatological Data hourly observations at Palo Alto Airport across the ten Julys 2015-2024 (Local Standard Time) gives 86.6% relative humidity at 05:00 (n=250) and 62.7% at 16:00 (n=235). The station reports only between about 05:00 and 19:00, so no overnight figure exists for it. For contrast, NOAA's Comparative Climatic Data table gives Sacramento a July afternoon mean of 29%. Palo Alto summers running near 79°F pull indoor humidity down hard whenever the air conditioning is working. Solid hardwood answers that by shrinking, which is what opens seasonal gaps between boards. The fix is not a tighter install — it is acclimating the wood to the house's real conditions before it goes down, and setting expansion space at the walls to match the swing this climate actually produces.

NOAA 1991-2020 normals at the Palo Alto station give January an average high of 57.8°F and an average low of 39.0°F; December's 38.6°F is the coldest average low. Annual precipitation normal is 15.12 inches, with February the wettest month at 3.18 inches. Winter runs the same cycle in reverse. Solid hardwood is a hygroscopic material: it moves with the seasons for its whole service life, and an install that ignores that is an install that telegraphs every season change through the floor.

Palo Alto's July normal high of 79.4°F runs about 13°F above San Francisco Downtown (66.3°F) and just below San Jose's airport station (80.8°F). Whatever the outdoor pattern in Palo Alto, solid hardwood responds to the air inside the house, so the wood acclimates to the rooms it is going into rather than to a delivery truck or a garage.

Measured Humidity and Solid Wood Movement in Palo Alto

Moffett Federal Airfield, 5 miles from Palo Alto and 117 feet lower, supplied the 66,906 hourly dewpoint readings, 2015 to 2025, behind these figures. Warm that winter air to 70°F without adding moisture and it settles at a median 40.1% relative humidity, with 16% of heating-season hours below the 30% floor NWFA sets for wood floors; the same air reaches 61.2% in summer. Solid hardwood follows those numbers: its equilibrium moisture content runs from about 7.7% in the heating season to 11.2% in summer, and on the Forest Products Laboratory's coefficients for American white oak that swing changes the width of a 5-inch plainsawn board by about 0.066 inch (about 1/15 inch) — against 0.034 inch for the same board quartersawn. That is a mild climate for solid wood, and it is why wider plank is a realistic choice in Palo Alto rather than a gamble.

Source: Hourly ASOS dewpoint observations 2015–2025, Iowa Environmental Mesonet (Iowa State University); equilibrium moisture content from USDA Wood Handbook FPL-GTR-190 Eq. 4-5; movement from FPL-GTR-282 Eq. 13-3 and Table 13-5

Subfloor and Foundation Work

The city's adopted Eichler Neighborhood Design Guidelines (April 2, 2018) state that of the more than 11,000 homes Joseph Eichler built, 'some 2,700 were located in Palo Alto' — elsewhere the same document says 'well over 2,000' — across 31 tracts built between 1949 and 1974. As typical characteristics, the guidelines describe a 'post and beam construction method, built on a concrete slab foundation,' with 'Radiant heating is embedded in the concrete slab flooring,' and warn that the original radiant heating system 'may be difficult to repair without highly invasive intervention.' 70.0% of Palo Alto housing predates 1980. CRMP's 2025 Earthquake Brace + Bolt list, with eligibility 'based on ZIP Code only,' includes 94301, 94303, 94304 and 94306, ZIPs that contain Palo Alto addresses, for a program limited to 'wood-framed, pre-1980 homes with a raised foundation.'

Over a crawlspace, solid hardwood is in its element — plank or plywood subfloors take fasteners well — but only when the crawlspace itself is dry. We check the ground cover, look for standing water and rot at the joist ends, and read the moisture content of the subfloor from below. Cupping in a solid floor is almost always a crawlspace problem that surfaced upstairs.

Source: NAHB analysis of the Census Bureau Survey of Construction, foundation type by region (2024)

Palo Alto Homes We Work In

ACS 2020-2024 five-year estimates count 29,241 housing units, with a median year built of 1963. The 1950s alone account for 25.1% (7,341 units), the largest single decade. 13.3% were built in 1939 or earlier and 12.1% in the 1960s. 58.9% of the stock predates 1970. Palo Alto's 1950s, pre-1940, and 1960s stock is directly relevant here, because homes of that period frequently have a board or plywood subfloor that will hold a nail-down installation, and sometimes original wood still under the carpet. We check for both before quoting a full replacement — refinishing what's already there is often the better answer.