Wood rot, termite damage, and structural decay are the three wood pathologies most homeowners encounter, and they demand different responses. This guide explains what each one is, how to spot it before it advances, what it actually does to the structure of your home, and when repair makes sense versus replacement. Denver's high-altitude semi-arid climate, intense freeze-thaw cycles, and frequent hailstorms create their own particular wood-damage profile, different from coastal regions or humid lowlands. Understanding that profile helps you read the condition of your own home and make informed decisions.
This guide is written for Denver homeowners and those in surrounding areas who have noticed something amiss: a soft spot in a deck, paint that blisters at a window sill, a floor that feels springy, or a pest inspection that turned up damage. It explains what you are looking at, what it means, and how the repair process actually works. You will finish it better informed than when you arrived, and you will understand why an honest contractor quotes you more than one option.
Dry Rot and Wet Rot: Not the Same Problem
Dry rot and wet rot are both fungal decay, but they require different moisture conditions and behave very differently. Dry rot is caused by a fungus that needs sustained moisture in the wood, but not standing water or active dripping. It spreads through the wood grain, breaking down the cellulose, and can even travel across masonry to reach new timber. The wood becomes brittle and develops a distinctive cubical cracking pattern, as if the grain has fractured into small cubes. The texture is dry and crumbly, almost powdery to the touch. Wet rot, by contrast, requires a persistent direct water source such as a leaking gutter, a failed flashing, or contact with wet soil. It stays localized to that water source and does not travel through the structure. Wet-rotted wood looks and feels darkened and spongy, soft rather than brittle.
Both types can hide beneath a paint film that looks perfectly intact. Paint can seal moisture into the wood underneath while the surface appears sound, which is why visual inspection alone is unreliable. A screwdriver or awl pressed into the wood is the real test. Dry rot tends to occur where moisture is intermittent or where humidity is sustained but drainage is poor, such as at a sill plate where rainwater collects, or in a rim joist where condensation accumulates. Wet rot appears where water is actively present, such as around a failed deck ledger or a window that leaks. In Denver's dry climate, dry rot is far more common than wet rot, but both occur, and both require the water source to be identified and closed before any wood repair will last.
Termite and Beetle Damage, and How It Differs from Rot
Termites and wood-boring beetles cause structural damage through entirely different mechanisms than fungal decay, and they are identified and treated by a different trade. Termites are social insects that tunnel through wood along the grain, hollowing out the interior while often leaving a thin shell of sound wood at the surface. They typically travel in mud tubes on masonry to reach timber above grade. Wood-boring beetles, such as powderpost beetles, lay eggs in wood, and the larvae tunnel through it as they develop. They leave behind small exit holes (often 1/16 inch or smaller) and a fine sawdust-like waste called frass. Both types of insect damage can be extensive inside the wood even when the outside looks relatively normal, which is why a pest inspection report is the starting point, not a visual survey.
Insect damage and fungal decay often occur together because the same moisture that invites termites or beetles also invites rot. A floor joist that has been hollowed by termites is also likely to have some fungal decay at the same location. Once a pest control operator licensed or registered in your state has identified and treated any active infestation, a carpenter's job begins: removing the damaged wood and replacing it with sound material. The carpenter works from the pest inspection report and rebuilds the structure. Treating or eliminating insects is not a carpentry task, and no carpenter can make that claim. The division of labour protects you: the pest operator handles the insects, and the carpenter handles the wood.
Reading the Signs Before You Open Anything Up
Before you call a contractor, you can gather useful information by looking and listening carefully. Paint that blisters, peels, or holds moisture at window sills and door thresholds often signals trapped water. Trim or fascia that gives easily under thumb pressure, or into which a screwdriver sinks with little resistance, has lost structural integrity. A deck board that flexes or feels soft underfoot, or a joist that gives when you press on it, indicates decay or insect damage. Doors and windows that have shifted in their frames, or that stick or close unevenly when they did not before, sometimes signal movement in the framing caused by loss of section in a sill plate or header. A musty or earthy smell in a basement, crawlspace, or enclosed area suggests sustained moisture and possible decay nearby. A floor that feels noticeably soft, bouncy, or out of level compared to adjacent areas is worth investigating promptly.
These signs are worth noting, but they do not tell the whole story. Surface appearance often understates the extent of decay. Paint can hide damage, and a thin shell of sound wood can conceal serious hollowing inside. Probing with a screwdriver or awl is how a contractor actually determines what is there. A careful probe will find soft spots, measure how far decay extends, and distinguish between surface blemish and structural loss. This is why a free estimate always includes hands-on inspection, not just a visual walk-through. The goal is to know what you are dealing with before any decisions are made.
What Decay Does to a Floor, a Deck and a Wall
To understand what decay does to your home, it helps to trace the load path: the way weight travels through the structure. A floor is supported by joists that span between beams or bearing walls. Those joists rest on a sill plate, which sits on the rim joist (the outer band of framing). The rim joist is the vertical member that closes off the end of the floor system. A deck is supported by joists that span from the house to posts in the yard, and those joists are attached to the house via a ledger board bolted to the rim joist or band board. Loss of section in any of these members means loss of stiffness first. A homeowner feels this as bounce or flex in the floor or deck long before any structural failure occurs. The bounce comes from the member bending slightly under load because it has less cross-sectional area to resist bending. This is the most common complaint and the earliest sign that decay has advanced enough to matter.
The connection where a deck ledger bolts to the house is the single most critical connection in a deck system. If that connection fails or if the wood it is bolted into has decayed, the deck can separate from the house, which is dangerous. A sill plate that has lost section to rot can no longer support the weight of the walls above it, and the building will settle unevenly. A floor joist that is hollow from termite damage or soft from rot will sag and bounce. These are progressive failures, not sudden ones. The wood does not fail all at once. It loses stiffness first, which you feel as movement, then it loses strength. This is why inspection and repair before the damage is severe is the right approach: you catch the problem while options still exist.
Repair or Replace: The Actual Criteria
The decision to repair or replace a damaged member comes down to four practical criteria. First, how much sound section does the member have left? A joist that is 50 percent decayed and 50 percent sound might be a candidate for repair. A joist that is 80 percent gone should be replaced. Second, where is the decay located? Decay at a bearing point (where the joist sits on the sill plate or rim joist) is more serious than decay in the middle of the span, because the bearing point carries the reaction load. Third, can the water source actually be closed? If the decay is caused by a leaking gutter or a failed flashing, and that source can be repaired or rerouted, then repair of the wood makes sense. If the water source cannot be closed, replacement is the only honest answer because the new wood will decay the same way. Fourth, how do the two costs compare once access and labour are counted? Sometimes replacement is cheaper than repair once you factor in the cost of opening up the area, removing the damaged section, and installing a sister joist or consolidant.
Sistering is a common middle-ground repair: bolting a new joist or beam alongside the damaged one to share the load. It works when the sound section of the original member is sufficient and the water source is closed. Epoxy consolidants and wood fillers have a real but narrow use on non-structural profiled trim, such as crown molding or decorative casing, where the wood is worth saving for its craftsmanship or finish. They are not a repair for structural members. Filling a rotted joist with epoxy and calling it repaired is not honest work. A good contractor will quote you both options where both are real: repair by sistering, or replacement. The estimate will explain why one makes more sense than the other given your particular situation. You can then decide which path to take. See our pricing page for a sense of what these repairs typically cost.
Who Does What: Carpenter, Pest Operator, Engineer
Wood decay and structural damage involve several different trades, and understanding who does what protects you from wasted money and incomplete work. A pest control operator licensed or registered in your state identifies active termite or beetle infestations and treats them. A carpenter removes damaged wood and rebuilds the structure with sound material, closing the water source if possible. A licensed structural engineer sizes beams, calculates loads, and specifies repairs where the structure is compromised. Alterations to load-bearing walls, beam replacements, and significant joist repairs commonly require an engineer's design and a building permit. The building department (in Denver, the Department of Community Planning and Development) reviews plans, issues permits, and inspects the completed work. Each role matters, and skipping a step usually leads to problems later.
Denver Carpentry is the carpenter in this chain. We are fully insured and we remove and replace damaged wood, close water sources, and rebuild the structure to sound condition. We do not treat insects or pests (that is the pest control operator's licensed trade), we do not size beams or design structural alterations (that is the structural engineer's role), and we do not pull permits (that is the building department's requirement, and we help you understand when one is needed). If your situation requires an engineer or a permit, we will tell you plainly. If you need a pest inspection, we will work from that report. If you have questions about your home or want to schedule an inspection, call us at (720) 807-5448 or request a free estimate.