2026 Oregon Home Award WinnerMost dry rot repairs in Portland cost between $1,500 and $40,000. A rotted windowsill or a run of fascia sits at the low end; a siding elevation or deck framing with the flashing corrected sits at the high end. Structural work, meaning beams, posts, joists, and sheathing replaced under permit, runs $40,000 to $150,000, and whole-envelope rebuilds on multi-unit buildings start at $150,000. Those are real numbers from a licensed Portland contractor that does this work every month (Oregon CCB #233813, verify), not a national calculator’s guess. This guide explains what moves a dry rot bill from one tier to the next, what you’re paying for, and the two decisions that decide whether you pay once or twice.
Portland Dry Rot Repair Costs at a Glance
Spot Repair, $1,500 to $8,000
A windowsill, a stretch of trim or fascia, a deck post or a few deck boards. Rot cut out, surrounding wood treated, the piece rebuilt and painted. A recent deck rot repair came in right around $3,000.
Section Repair, $8,000 to $40,000
A full siding elevation, deck framing, or several framing members, with the moisture barrier and flashing corrected so the water that caused it has somewhere else to go.
Structural Repair, $40,000 to $150,000
Beams, posts, joists, and sheathing replaced with shoring, engineering, permits, and inspections, plus window replacement where the rot came in around the frames.
Multi-Unit and Whole-Envelope, $150,000+
Condo and apartment buildings where the rot is in the structure across the whole exterior. Our recent condo overhauls ran $200,000 and up per building: structure, siding, and windows, sequenced around the residents.
What Each Tier Actually Buys
Ranges are honest but abstract, so here is the same information the way we explain it on site.
Around $3,000 buys a spot repair done properly. We cut the rotted section back to sound wood, not just the soft part you can press a thumb into, treat what stays, rebuild the piece in matching stock, and flash or seal the reason it got wet. If the cause is a failed bead of caulk or a missing drip edge, the fix is small and the repair holds.
Between $8,000 and $40,000 is where most of the dry rot we see lands, because by the time a homeowner calls, the rot has usually traveled. One soft spot on the siding turns out to be a run of sheathing and the bottom plate behind it. At this tier you are paying for a crew to open the wall, map the extent, rebuild the framing, re-sheathe, and put the weather barrier, flashing, and siding back the right way. The siding and trim get matched to the house so the repair disappears.
From $40,000 up, the rot has reached the parts of the house that hold it up. Beams, posts, rim joists, roof joists. This is permitted work. An engineer sizes the replacement members, we shore the structure, cut out and replace, and the City inspects as we go. Our Brooklyn roof project this fall is a good picture of this tier: a flat roof whose deck had rotted from the inside under a perfectly intact membrane, 35 joists replaced or sistered, a new deck and insulation, 320 crew hours over four days, with permits and a structural engineer on the job. The full story is on our dry rot repair page.
At $150,000 and beyond, you are usually a condo association or a property manager, and the question is no longer “what does this cost” but “how do we do this once.” Those projects are run in phases around occupied units, with engineering, permits, and a written scope the board can approve.
Want to know which tier you’re in?
Free inspection and a line-item estimate for exactly what we find. Response within one business day.
What Makes Dry Rot Repair Cost More (or Less)
Two repairs can look identical from the sidewalk and differ by $30,000. These are the variables that move the number.
- ✓ How far it traveled. Rot works inward and along the grain. The visible damage is almost never the whole scope, which is why we open the assembly before we price it.
- ✓ Whether it reached structure. Trim and siding are carpentry. Beams and joists are engineering, shoring, and permits. That line is the biggest jump in cost.
- ✓ The water source. A failed flashing is cheap to correct. A roof that was re-covered without a tear-off, or grading that sends water at the foundation, costs more to fix and cannot be skipped.
- ✓ Access and height. Ground-level siding is quick. Second-story walls, roof decks, and anything that needs scaffolding or a crane add setup time and safety work.
- ✓ Matching the house. Older Portland homes have siding profiles and trim details that are not on the shelf. Milling to match costs more than modern lap siding and is worth it.
- ✓ Windows and doors in the path. Rot that entered around a window usually means the window comes out, and often means it gets replaced while the wall is open.
- ✓ Occupied buildings. Multi-unit work is sequenced around tenants, which adds planning, protection, and time.
- ✓ Season. Open walls in a Portland winter need weather protection every day. Dry-season work is cheaper and faster.
Where the Money Goes
On a typical section repair, labor is the largest line, because the work is diagnostic and careful rather than fast. Opening up, cutting back to sound wood, treating, rebuilding, and closing up correctly is skilled carpentry, not demolition. Materials are the smaller share: framing lumber, sheathing, weather barrier, flashing, matched siding and trim, fasteners, and paint. On structural tiers, add engineering, the permit itself, shoring equipment, and inspections. Where rot came in around openings, add the window or door.
The line you should never see on a dry rot estimate is “patch and fill.” Wood filler over soft wood is a cosmetic repair of a structural problem, and it is the reason some houses pay for the same rot twice.
Where You Can Save, and Where You Shouldn’t
Save by catching it early. Dry rot with a steady water source spreads season to season, not year to year. A soft windowsill this winter can mean sheathing and framing next winter. The cheapest dry rot repair is the one you call about the week you notice it.
Save by bundling. If siding or windows are on your list anyway, do the rot repair in the same mobilization. The wall is open once, the crew is there once, and the flashing is done right for both jobs at the same time.
Save by phasing, not by skipping. On larger scopes we can sequence the work so the water source and the structural members come first and the cosmetic finish follows. What we will not do is close a wall over rot to hit a number.
Do not save on the water source. Every dollar spent rebuilding wood is wasted if the leak, the flashing, or the drainage that caused it is left alone. We trace the moisture to its origin before we price the repair, and the fix for the source is on the estimate, not an afterthought.
Permits, Engineering, and Timelines
Most dry rot repairs need no permit. Trim, siding, decking, and non-structural framing are repair work. When structural members are replaced, meaning beams, posts, joists, or load-bearing framing, the City of Portland requires a permit, and the repair is usually sized by a structural engineer first. Allow three to four weeks for that approval. Multi-unit buildings add their own requirements. We handle the permits, the engineering coordination, and the inspections as part of the project, and the permit clock runs before the first cut, so the earlier the call, the sooner the work starts.
On site, spot repairs are usually a matter of days. Section repairs typically run a week or two depending on access and weather. Structural work runs in weeks and is scheduled around the permit and inspection stages. Our dry rot repair page walks through the six steps from the first inspection to the final paint.
Is Dry Rot Repair Worth It?
Dry rot is the rare home repair that genuinely gets more expensive every month you wait, because the fungus keeps eating as long as the wood stays damp. A $3,000 sill repair left alone becomes a $15,000 wall repair, and a wall repair left alone becomes a structural job with an engineer on it. It also shows up at the worst time: in a home inspection when you sell, or in a ceiling that starts to stain. Repairing it properly, with the water source fixed, restores the house to sound and stops the clock. We back our workmanship with a one-year warranty, in writing.
Portland Dry Rot Repair Cost FAQ
How much does dry rot repair cost in Portland?
Spot repairs typically run $1,500 to $8,000, section repairs $8,000 to $40,000, and structural work $40,000 to $150,000. Multi-unit envelope rebuilds start at $150,000, and our recent condo overhauls ran $200,000 and up per building. The honest number comes from opening up the assembly, which is why we start with a free inspection and an itemized estimate.
What does dry rot repair cost per square foot?
Dry rot is not priced by the square foot, because the cost depends on how deep the damage goes, not how wide. Ten square feet of siding over sound sheathing is a small job; the same ten square feet over a rotted rim joist is a structural one. We price by the assembly we actually find, line by line.
Is dry rot covered by homeowners insurance?
Usually only when it results from a sudden, covered water event. Slow leaks and long-term moisture are typically excluded as maintenance. Every policy differs. We document everything we open up with photos, which is exactly what you need if a claim is possible.
Why is dry rot repair more expensive than it looks?
Because the rot you can see is the end of the problem, not the start. It travels inside the wood, along the grain, behind siding and under flooring. A proper repair cuts back to sound wood and fixes the water source, which is more carpentry than the soft spot suggests. Patching the visible part is cheaper and does not last.
Do I need a permit to repair dry rot in Portland?
Not for trim, siding, decking, or non-structural framing. Replacing beams, posts, joists, or other load-bearing members is permitted work, usually with a structural engineer’s sizing, and approval typically takes three to four weeks. We handle the permit, the engineering coordination, and the inspections.
Can I just use wood filler or epoxy on dry rot?
On a small, dry, non-structural spot with the water source already fixed, a consolidant can be a reasonable cosmetic repair. On anything soft enough to push a tool into, anything structural, or anything still getting wet, filler hides the problem while the fungus keeps working. We cut back to sound wood instead.
How fast does dry rot spread?
With a steady moisture source, noticeably from one season to the next. A soft sill this winter can mean sheathing and framing repairs by next winter. It is the rare repair that gets more expensive the longer you wait.
Does the repair include fixing the leak that caused it?
Yes. We trace the moisture to its source, whether that is flashing, a roof, grading, or plumbing, and the fix for the source is on the estimate. Rebuilding wood without stopping the water is the one way to pay for dry rot twice.
How do I get an exact price for my dry rot repair?
Start with a free inspection. We probe the visible damage, trace the moisture, and tell you what we expect to find. If opening a small area is needed to price it honestly, we say so. You get a line-item estimate for the actual scope, and you can request it online.
Ready to find out what you’re dealing with? See our Portland dry rot repair work, including the Brooklyn roof rebuild, read our 5-star Google reviews, then request your free inspection and itemized estimate.
