Repairing rotted joists and framing under a house in the Birmingham area typically costs $1,000 to $10,000, with sistering a single joist at $200 to $1,000 and full replacement at $500 to $2,500 per joist, according to HomeGuide's April 2026 floor joist repair guide. A rotted sill plate is a bigger job, at $120 to $200 per linear foot in HomeGuide's September 2025 sill plate guide, because the house has to be lifted off the foundation to replace it. Rot is a moisture problem first: the USDA Forest Products Laboratory's Wood Handbook says serious decay occurs only when wood is wetter than its fiber saturation point, about 30 percent moisture, and that wood kept air dry will not decay. BDry Alabama repairs or reinforces the damaged wood, then recommends the moisture control that keeps it dry, starting with a free inspection.
We repair wood rot under the house for homeowners in Birmingham, Hoover, and the surrounding towns. Reach out for local pricing and a free estimate.
Birmingham's housing is old by Alabama standards: Census ACS 2023 estimates put the median home at 1965, with about 42 percent of the city's 108,903 housing units built before 1960. The typical Birmingham home dates to around 1965 per Census data, roughly 61 years of Alabama weather and daily use. Call (205) 942-1976 or book a free estimate for Birmingham pricing. More on Birmingham
Hoover is a newer suburb: Census ACS 2023 estimates put its median home at 1994 across 39,090 housing units, with about 71 percent owner occupied. The typical Hoover home dates to around 1994 per Census data, roughly 32 years of Alabama weather and daily use. Call (205) 942-1976 or book a free estimate for Hoover pricing. More on Hoover
BDry Alabama handles wood rot repair in all 28 of these cities and the towns around them. Linked cities have their own local page. See every service area.
These are typical installed ranges from HomeGuide's April 2026 floor joist repair guide and September 2025 sill plate guide, not quotes. How far the rot has spread, which pieces of framing it reached, and how much room there is to work set your price, which comes from a free inspection.
| Wood rot repair | Typical installed range |
|---|---|
| Sistering a rotted joist, per joist | $200 to $1,000 |
| Replacing a joist, per joist | $500 to $2,500 |
| Adding support posts or a beam | $1,000 to $5,000 |
| Replacing several joists in a section | $5,000 to $20,000 or more |
| Sill plate replacement, per linear foot | $120 to $200 |
| Sill plate replacement, 25 linear feet | $3,000 to $5,000 |
| Structural engineer's assessment, when required | $300 to $800 |
Figures are typical ranges and vary by project. Your free estimate is exact.
BDry Alabama measures your project and gives you a clear written estimate at no cost.
We are a local foundation repair and waterproofing contractor and we stand behind every job. You are not handed off to a subcontractor. Every job follows the same disciplined process:
Decay fungi need wood, moisture, air and mild temperatures, and a crawl space here supplies all of them for months. The USDA Forest Products Laboratory's Wood Handbook puts the best growing temperature for most decay fungi at 77 degrees, with decay slowing below 50 degrees. NOAA's 1991 to 2020 climate normals for the Birmingham airport station put the July average low at 72.1 degrees, so the air under a house sits near that sweet spot all summer. The Handbook also says humid air by itself will not wet wood enough for serious decay; the water comes from condensation, leaks and wet ground, and it names soil moisture as the main source of condensation in crawl spaces. That is why rot here so often starts on the joists and sills over bare dirt.
Repairing rotted floor framing typically costs $1,000 to $10,000, with an average near $5,000, according to HomeGuide's April 2026 floor joist repair guide. A single joist that can be sistered runs $200 to $1,000, replacing one runs $500 to $2,500, and replacing several joists in a section runs $5,000 to $20,000 or more. Rot in the sill plate, the board that sits on top of the foundation wall, costs more because the house has to be lifted to reach it: HomeGuide's September 2025 sill plate guide puts it at $120 to $200 per linear foot, or $3,000 to $5,000 for a 25 foot section. On top of the wood itself, the moisture source has to be fixed, whether that is a plumbing leak, poor drainage or a damp crawl space. BDry Alabama finds where the rot stops and gives you one written price after a free inspection.
Wood that stays wet long enough for decay fungi to grow. The USDA Forest Products Laboratory's Wood Handbook says serious decay occurs only when wood moisture content is above the fiber saturation point, about 30 percent, and that humid air alone will not wet wood that far; the water has to come from rain, condensation or contact with wet ground. Under a house, that usually means ground moisture rising from uncovered soil, poor airflow that traps damp air, gutters and grading that send water toward the foundation, or a plumbing leak or sweating pipe dripping on the same spot. The Handbook names soil moisture as the main source of condensation on floor framing over crawl spaces and recommends covering the soil with a barrier such as polyethylene. Find the source first, because new wood in the same conditions rots the same way. BDry Alabama traces the moisture during the inspection.
Look, then probe. Rotted framing is often darker or stained, sometimes bleached, and may be warped, cracked, flaky or crumbly at the surface. The USDA Forest Products Laboratory's Wood Handbook describes the two main kinds: brown rot leaves wood brown and cracked across the grain into cube shapes that can be crushed to powder, while white rot leaves it bleached and often spongy without shrinking. Healthy wood resists a probe. HomeGuide's April 2026 floor joist repair guide suggests pushing a screwdriver into suspect spots; if the wood is soft or the tip sinks in easily, the joist has likely lost significant strength. From inside the house, watch for a soft spot in the floor, a floor that bounces, or a musty smell. Check where water gathers: under bathrooms and the kitchen, along the outside walls, and anywhere insulation hangs wet. BDry Alabama checks suspect areas on the beams and joists at the inspection.
Many can be repaired. If the rot is limited and most of the joist is still sound, sistering a new board alongside it restores the strength without removing the old one, and HomeGuide's April 2026 floor joist repair guide prices that at $200 to $1,000 per joist. Steel flitch plates are another reinforcement option at $300 to $1,200. When rot runs through the full depth or length of a joist, it has to come out, and full replacement runs $500 to $2,500 per joist because the floor above has to be shored and some subfloor may come up. The USDA Forest Products Laboratory's Wood Handbook adds a rule that matters more than the method: if the moisture that caused the decay is eliminated, the weakened wood only needs to be replaced with dry lumber, but if it cannot be, use preservative treated or naturally decay resistant wood. BDry Alabama probes each joist before recommending either.
The sill plate is the horizontal board bolted on top of the foundation wall. HomeGuide's September 2025 sill plate guide explains that it spreads the weight of the house across the foundation and gives the floor joists, rim joists and wall framing a level surface to attach to, and the ends of the floor joists rest on it. Because it sits at the outside edge, a sill takes the water from overflowing gutters, soil piled against the foundation and splash from the ground. When it rots, the walls and the joist ends above it lose solid bearing, and floors along the outside wall can dip. Replacing one is major work: HomeGuide says the house is lifted 1/4 inch to 3 inches with hydraulic jacks, one section at a time, at $120 to $200 per linear foot, and the job takes 1 to 5 days. BDry Alabama looks for affected wood and the moisture behind it as part of the inspection.
No, and the name is misleading. The USDA Forest Products Laboratory's Wood Handbook says brown, crumbly rot in the dry condition is sometimes called dry rot, but the term is incorrect, because wood must have moisture available for decay to happen, even if it dries out later. Some brown rot fungi can grow strands that carry water, usually from the soil, into wood that would otherwise stay dry, which is how rot can show up in framing that seems far from any leak. The practical point is the same either way: the wood got wet, and it will keep decaying while it stays above the fiber saturation point, about 30 percent moisture per the Handbook. Dry crumbly wood found in a crawl space today is a record of moisture that was there, and may still be on wet days. BDry Alabama looks for the water path, not just the damaged board.
Keep the wood dry, because the fungi never leave. The USDA Forest Products Laboratory's Wood Handbook says decay spores are everywhere, so controlling moisture is what prevents decay, and that fully air dried wood, usually no more than 20 percent moisture, gives a reasonable margin of safety. Under a house that means covering the soil, sealing out humid air, and dehumidifying, which is what crawl space encapsulation does; sending gutter and surface water away from the foundation; and fixing plumbing leaks and sweating pipes promptly. The EPA's mold guide sets the indoor humidity target below 60 percent, ideally 30 to 50, and that applies under the floor too. The Handbook also recommends at least 8 inches between soil and framing, so pull back mulch and beds that have crept up the foundation. BDry Alabama recommends the moisture control that fits the house once the repair is done.
It can be, depending on what it is holding up. Joists and beams carry the floor, and sill plates carry the walls, so rot in any of them reduces how much load the structure can safely bear. Early on, the signs are a soft spot, a bounce or a slight dip. Left alone, the floor can sag further, doors and windows can bind as the framing shifts, and cracks can open in walls and ceilings, all listed as warning signs in HomeGuide's April 2026 floor joist repair guide. The same guide says properly maintained joists can last 75 to 100 years or more, and that keeping them dry and free of pests is the key, so rot in a younger house means something is keeping the wood wet. A sudden collapse is rare, but a soft area near a heavy tub or appliance should be checked soon. BDry Alabama can tell you at the inspection what needs attention first.
Usually not for slow rot. HomeGuide's April 2026 floor joist repair guide says homeowners insurance typically covers joist damage from sudden, accidental events like a burst pipe or storm damage, but generally does not cover damage from long term neglect, gradual deterioration, termites or normal wear and tear. Rot that built up over years from a damp crawl space or a slow leak usually falls into the excluded group. A sudden pipe failure that soaked the framing may be different, so read your own policy and file promptly if the cause was sudden. Dated photos of the damage and the leak help an adjuster. Either way, the fix is cheaper early: HomeGuide puts sistering one joist at $200 to $1,000, against $5,000 to $20,000 or more once several joists in a section have to be replaced. BDry Alabama explains what it finds in plain language at the inspection.
Call BDry Alabama at 205 942 1976 or send the form, Monday through Friday from 7 in the morning to 6 in the evening. Tell us what you are noticing, such as a soft spot in the floor, a musty smell, or dark or crumbling wood you saw through the crawl space door. At the visit we go under the house, find the damaged wood, check the beams and joists, and trace the moisture that caused it, whether that is uncovered soil, poor airflow, drainage toward the foundation or a plumbing leak. You get a plain explanation and one written price, with no pressure to decide that day. For scale, HomeGuide's April 2026 floor joist repair guide puts most repairs at $1,000 to $10,000, and catching rot while a joist can still be sistered keeps the job near the low end of that range.
BDry Alabama
1490 Valley Drive, Bessemer, AL 35022
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