Foundation calls in the Huntsville area cluster at two times of year: late in a dry autumn, when doors stick and new cracks open, and late in a wet winter, when crawl spaces hold water and basement walls weep. That is the local climate working on local soils. This post walks through the NOAA normals, the four years that show the extremes, what NRCS soil data says about how the ground moves, and the drainage habits and timing that help. Huntsville Foundation Quotes connects Huntsville-area homeowners with independent local foundation repair, crawl space and waterproofing companies for free, no-obligation quotes; those companies do the work described here.
The seasonal pattern in the NOAA normals
NOAA’s 1991–2020 climate normals for Huntsville International Airport give the city 54.29 inches of precipitation a year. The distribution is the point. December is the wettest month at 5.87 inches, and the December-through-February season brings 15.97 inches, the most of any season. September is the driest month at 3.49 inches, with August (3.55) and October (3.56) close behind, and the September-through-November season is the driest at 11.30 inches. Huntsville averages 15.5 days a year with an inch or more of rain, led by December at 1.8 days and March at 1.6. On the temperature side, 55.6 nights a year fall to 32°F or below, 16.2 of them in January, the median first freeze is November 8, and snowfall averages 2.4 inches.
Put together, that is a wet-winter, dry-fall climate with a gap of nearly five inches between its wettest and driest seasons. Late summer into fall dries the clay under slabs and footings; December through March saturates it, fills crawl spaces and loads basement walls. The 55.6 freezing nights are mild by northern standards, so frost heave is a secondary issue here; the primary drivers are drying and wetting.
Four years that show the extremes
Four dated years show the ends of the range, each sourced to NWS Huntsville, the station record or the UAH Alabama Climate Report.
2007 was the driest year in the Huntsville record at 28.65 inches. NWS Huntsville’s history timeline records a moderate to exceptional drought across its forecast area that year. 2016 brought a record dry fall: September recorded 0.47 inches and October 0.77 inches, per the UAH Alabama Climate Report as summarized, and NWS Huntsville describes a drought that developed in mid-May, peaked in October and November with all of north Alabama in extreme to exceptional drought, and eased only from late November.
2009 was the wet counterpart at 67.70 inches, and on December 8–9 of that year NWS Huntsville recorded four to eight inches of rain across Madison, Morgan, Lawrence, Jackson and DeKalb counties with widespread flash and river flooding in Morgan and Madison counties. 2020 reached 70.52 inches, Huntsville’s fourth-wettest year, per the UAH Alabama Climate Report as summarized. The sequence matters more than any single year: a dry fall that shrinks the soil, followed by a saturating winter that swells it, is the cycle that opens stair-step cracks in brick and block and sends water into crawl spaces. Our soils and sinkholes post covers the ground side of that story in detail.
What shrink and swell do, by soil type
How much the ground moves depends on the clay. The NRCS measures shrink-swell as linear extensibility (LEP) and rates it low below 3, moderate from 3 to 6, high from 6 to 9 and very high above 9. Its SSURGO data for Madison County shows the famous Tennessee Valley red clay is not the worst offender. The Decatur series, 13.0 percent of the county, has a subsoil with 57 percent clay but an LEP of 3.1, low to moderate; Dewey and Cumberland come in at 4.5, moderate. Barfield, the county’s largest series at 13.2 percent, is a shallow clay over limestone ledges rated high at 7.5, and the smectitic Colbert series rates very high at 12.3 in its subsoil. Weighted by acreage, about 17.5 percent of Madison County and 18.7 percent of Morgan County sit in soils with a high or very high shrink-swell horizon, against 1.3 percent of Limestone County. A Web Soil Survey lookup of your own parcel is free; no source maps neighborhoods to named soils, so we do not.
On a slab, a dry September pulls moisture from the clay around the perimeter first, so the edges lose support before the center does; the slab tilts toward the dry edge, drywall cracks appear at door and window corners, brick shows stair-step cracks and doors that closed in June stick in October. When winter rain returns, the perimeter swells back, sometimes unevenly. On a crawl-space house the same cycle works on the pier pads and perimeter footing, and water adds a second problem: a December with 5.87 inches fills low crawl spaces, saturates the soil around block walls and raises humidity under the floor. Basement walls take the load of saturated backfill, which is when bowing and horizontal cracks get noticed. The Geological Survey of Alabama also lists a drop in the water table from drought and excessive rainfall among the triggers for sinkholes in north Alabama’s carbonate terrain, one more reason the dry-then-wet sequence deserves attention on limestone ground.
Drainage and gutter habits that help
Most of what a homeowner can do is about water, and most of it is cheap compared with piers. Keep gutters clear before the December peak and extend downspouts well away from the foundation. Make sure soil slopes away from the house on every side; a low spot against the wall becomes a pond in December. Look under the house after the first heavy winter rain, and again after the driest weeks of September for new gaps between soil and slab. Huntsville’s residential code amendments require drains around foundations that retain habitable space below grade and crawl-space grading to a drainpipe on new construction, a useful benchmark when a contractor proposes drainage for an older house. For exterior drainage or grading changes in an HOA, check your covenants first. The waterproofing and drainage page describes interior drains, sumps and exterior options.
When to schedule an evaluation
October and November, after the driest months and around the median first freeze of November 8, are when settlement cracks are most visible and dry-season gaps can be seen. February and March, after the wettest months, are when crawl-space water, seepage and wall movement show. Cracks that open and close with the seasons are worth photographing with a date and a ruler; a crack that keeps widening across a full year deserves a prompt look. A free contractor evaluation is a sales estimate, not an engineering opinion; when movement is significant, a report from an Alabama-licensed professional engineer is the independent view, and our foundation inspection page explains how the two differ. For cracks specifically, see foundation crack and wall repair.
Insurance, permits and licenses
Ask your insurer what your policy covers. In the City of Huntsville a permit is required when labor and materials exceed $250 or any structural work is involved (Inspection Department FAQ); the contractor pulls it and must hold a City of Huntsville business license. Alabama requires a Home Builders Licensure Board (HBLB) residential home builder license for any repair to a home when the cost exceeds $10,000 (Ala. Code §34-14A-2(16)); the HBLB says work that affects structural integrity needs the unlimited license, not the limited one; and licensees must show their license number in advertising and contracts (§34-14A-7). Ask for the company’s HBLB license number and check it on the HBLB lookup before signing. Jobs under $10,000 need no HBLB license. Ask for the warranty in writing: term, what voids it, whether it transfers to a buyer and any transfer fee.
Whichever season brought you here, written, itemized quotes from more than one independent company are the next step. Request free quotes through Huntsville Foundation Quotes and compare them side by side.
Frequently asked questions
When is the best time of year for foundation repair in Huntsville?
Problems show on a seasonal schedule: settlement cracks after the dry months of August through October, and crawl-space water or wall seepage after December through March, the wettest season at 15.97 inches. Contractors work year-round, so the better question is when to evaluate: after a dry fall for settlement, after a wet winter for water. Photograph cracks with a date and ruler in between.
Why do cracks open in September and close in winter?
Huntsville’s driest month is September at 3.49 inches and its wettest is December at 5.87, per NOAA’s 1991–2020 normals. Clay shrinks as it dries and swells as it wets, and NRCS rates about 17.5 percent of Madison County’s soils high or very high for shrink-swell. The perimeter of a slab dries first, so edges drop in fall and recover, sometimes unevenly, when winter rain returns.
Does homeowners insurance cover foundation movement from drought or rain?
Ask your insurer what your policy covers. Policies differ, and a quote service is not the right source for what any particular policy includes or excludes. What you can do on your own is keep dated photographs of cracks, keep gutters and grading in order through the wet season, and get written evaluations, including a professional engineer’s report where movement is significant.