Hardwood Flooring in Winters

Winters Conditions That Affect Solid Hardwood

Winters sits at about 135 feet in Yolo County. The regional Sacramento Valley record shows summer air cycling widely within each day rather than staying uniformly dry. In the National Weather Service publication "Climate of Sacramento, California" (revised August 2010), average relative humidity at Sacramento is 78 percent at 4 AM against 30 percent at 4 PM in July, a swing of roughly 48 points inside the same day. Those are Sacramento readings taken about 26 miles from Winters, not local measurements. Winters summers running near 95°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 for the Winters station record a January mean daily maximum of 56.5°F and mean daily minimum of 37.5°F, with January and December each averaging roughly 5 inches of precipitation. Winter is the wet season; summer months average near zero. 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.

Measured Humidity and Solid Wood Movement in Winters

University Airport, Davis, 10 miles from Winters and 66 feet lower, supplied the 62,832 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 37.4% relative humidity, with 24% of heating-season hours below the 30% floor NWFA sets for wood floors; the same air reaches 56% in summer. Solid hardwood follows those numbers: its equilibrium moisture content runs from about 7.3% in the heating season to 10.3% 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 0.056 inch (about 1/18 inch) — against 0.029 inch for the same board quartersawn. That is inside the range solid wood is specified for, but without much margin, so in Winters board width and cut get decided before species does.

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

Foundation type is not published for Winters, but the ground under the town is mapped in detail. USDA-NRCS SSURGO maps sixteen soil units inside the city limits. Brentwood silty clay loam is the largest at 31.4% of the incorporated area and carries a linear extensibility of 7.5%; Rincon silty clay loam covers a further 20.4% at 6.4%. NRCS rates any soil above 6% linear extensibility as high shrink-swell, and on that measure 57.9% of Winters sits on high-shrink-swell ground. What Winters does not have is any very-high soil: the most expansive unit in town, Capy silty clay, reaches 8.7% across 4.5% of the area, and nothing crosses the 9% threshold. Set against Dixon ten miles southeast, where no unit in the city rates above moderate at all, Winters is meaningfully more seasonally active ground — but it is not Diablo-clay country either.

On a slab, solid hardwood is the least forgiving floor there is: it cannot be nailed into concrete, and it responds to vapor drive from below more sharply than anything else we install. Where we're going over slab we test the concrete for moisture first — an in-situ relative humidity test per ASTM F2170 rather than a guess — and where the readings rule out solid wood, we say so and price engineered instead of hoping for the best.

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)

Winters Homes We Work In

ACS 2020-2024 five-year estimates count 2,564 housing units. The largest cohorts were built 1980-1989 (21.8%) and 1970-1979 (17.7%). Winters also retains a comparatively large pre-1940 cohort at 8.9% of units, alongside continued recent construction: 6.8% of units were built 2020 or later. Winters's 1970s-1980s, 2000s, and pre-1940 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.