Wood rot, termite damage, and structural decay are the most common reasons homeowners in Los Angeles call a carpenter. The city's Mediterranean climate, with its mild wet winters and warm dry summers, creates ideal conditions for wood-eating fungi and insects year-round. Add the region's mix of older masonry mansions, mid-century wood-frame homes, and newer stucco-over-wood-frame construction, and you have a building stock under constant pressure from moisture and insects.
This guide explains what rot and insect damage actually are, how to spot them before they advance, what they do to a floor or deck over time, and when repair makes sense versus replacement. It is written for homeowners who want to understand their own home's condition and make informed decisions about the work ahead, not for contractors or engineers.
Dry Rot and Wet Rot: Not the Same Problem
Dry rot and wet rot are two different fungal decay patterns, and understanding the difference matters because it tells you what to fix. Dry rot is caused by a fungus that needs sustained moisture in the wood, not standing water or active dripping. The moisture content needs to stay between roughly 20 and 30 percent for the fungus to thrive. Once established, dry rot spreads through wood along the grain and can travel across masonry surfaces to reach new timber. It causes cubical cracking and a dry, crumbly texture that breaks apart easily. The wood loses strength progressively, and because the decay often starts inside the member, the surface can look sound and well-painted even while the interior is compromised.
Wet rot requires a persistent direct water source, such as a leak, standing water, or constant splash. It darkens the wood and makes it spongy and soft to the touch. Unlike dry rot, wet rot stays localized to the wet area and does not travel through masonry. Both forms can hide under intact paint because paint itself holds moisture against the wood surface, especially at sills, thresholds, and trim joints where water pools or wicks. The paint film may blister or peel, or it may remain smooth and glossy while decay advances underneath. This is why visual inspection alone cannot determine the true extent of damage. Probing with a screwdriver or awl is the only way to know how much sound wood remains.
Termite and Beetle Damage, and How It Differs from Rot
Termites and wood-boring beetles damage wood in ways distinct from rot, though the two problems often occur together in the same member. Drywood termites, which thrive in Los Angeles' nearly year-round warm season, hollow wood from the inside along the grain, following the path of least resistance. They often leave a thin shell of sound wood on the surface, so the damage is hidden until that shell is probed or broken. Termites also build mud tubes on masonry surfaces as they travel between the soil and the wood above. Wood-boring beetles, by contrast, create exit holes as they tunnel out of the wood, and they leave behind fine sawdust-like frass in and around those holes. Both insects are attracted to wood that is already weakened by moisture or decay, because fungi soften the wood and make it easier to consume.
Identifying and treating insect infestations is the work of a licensed pest control operator in your state, not a carpenter. A carpenter's role is to remove and replace the wood that insects have damaged, working from the pest operator's inspection report and recommendations. Once the insects are treated and the water source is addressed, the carpenter rebuilds the framing or trim. This division of labor protects you: the pest operator is trained and licensed to identify live infestations and apply treatments; the carpenter is trained to assess structural integrity and rebuild it. Neither does the other's work.
Reading the Signs Before You Open Anything Up
Before you hire anyone to open up a wall or floor, you can gather clues about where decay or insect damage might be hiding. Look for paint that blisters, peels, or holds moisture at window sills, door thresholds, and exterior trim. Press the heel of your thumb against fascia, soffit, and trim boards, especially where they meet masonry or where water collects. Sound wood resists pressure; decayed wood gives under moderate thumb pressure. A screwdriver or awl pressed into these areas will sink into soft wood but will not penetrate sound wood. Check doors and windows to see whether they have shifted in their jambs or changed how they close and latch, which can signal movement in the framing. Walk slowly across floors and decks, feeling for soft or springy patches that flex under your weight. In basements, crawl spaces, or enclosed areas, smell for mustiness, which indicates persistent moisture even if you see no standing water. A deck ledger connection to the house is worth inspecting closely, as this is where water enters and where the connection matters most structurally.
None of these signs is an emergency, but they are worth investigating. Surface appearance often understates the extent of damage because decay advances from the inside outward and because paint can conceal it. A carpenter can probe suspect areas to determine how much sound wood is left and what the repair will entail. This probing is the first step and costs far less than opening up large areas.
What Decay Does to a Floor, a Deck and a Wall
To understand what decay does to your home, it helps to know what each structural member carries. A floor is built on floor joists that span between beams or walls and carry the weight of everything on that floor. The subfloor is nailed to the top of those joists and distributes point loads across them. The sill plate sits on the foundation and anchors the rim joist, which closes off the end of the floor frame and carries the load from the outermost joist. A deck is similarly built on joists that span between beams, and the ledger is the board that bolts the deck to the house and carries the deck's load into the house framing. When rot or insects remove wood section from any of these members, the remaining wood must carry the same load with less material, which means it works harder and deflects more. The first thing a homeowner feels is usually not a failure, but a loss of stiffness. A floor becomes bouncy or spongy underfoot. A deck board flexes more than it should. This is the wood asking for help.
As decay progresses, the deflection increases because less and less sound section remains. The member bends more, and the connections at its ends work harder. Over time, this can cause cracks in drywall, doors and windows to stick, and visible sagging. The progression is gradual, not sudden. Loss of section is the real problem, and it is measured by how much sound wood is left, not by how the surface looks. This is why probing is essential and why a carpenter who has seen the damage can explain what repair or replacement will cost and what timeline makes sense.
Repair or Replace: The Actual Criteria
Whether to repair or replace a damaged member depends on four practical criteria: how much sound wood section remains, whether the decay is at a bearing point where the member connects to the rest of the structure, whether the water source that caused the damage can actually be closed, and how the two costs compare once access and labor are counted. If a floor joist has lost 30 percent of its depth to decay but the decay is in the middle of the span and the wood is still structurally sound, repair by sistering (bolting a new joist alongside it) is often the right answer. If the decay is at the bearing point where the joist sits on the sill plate, or if the joist has lost so much section that it cannot carry the load safely, replacement is honest and necessary. The same logic applies to fascia, rim joists, deck ledgers, and framing.
Epoxy consolidants and wood fillers have a real but narrow use: they can stabilize non-structural profiled trim, such as crown molding or decorative casing, where the trim is worth saving for its appearance and the decay is shallow. They are not a repair for structural members, and putting filler over rot in a floor joist or beam is not a repair, it is a postponement. A good contractor will quote both repair and replacement where both are realistic options, explain the trade-offs, and let you decide. The pricing page describes how estimates are built, and you can request a free estimate to see both options for your situation.
Who Does What: Carpenter, Pest Operator, Engineer
Your protection as a homeowner lies in understanding who does what and holding each trade to its own work. A licensed pest control operator identifies live insect infestations and applies treatment. A carpenter assesses the wood damage, removes what cannot be saved, and rebuilds with new or salvaged material. A licensed structural engineer sizes beams, calculates loads, and specifies repairs where the structure has been compromised by decay or damage. The local building department permits structural work, inspects it, and enforces code compliance. Los Angeles Carpentry is the carpenter in this division of labor. We are fully insured, and we remove and rebuild damaged wood, close water paths, and repair framing and finish carpentry. We do not treat insects, perform engineering, or obtain permits on your behalf, though we can help you document damage for an insurance claim.
If your home needs structural repair, the building department will tell you whether a permit is required and whether an engineer's report is necessary. Requirements vary by the scope and location of the work, so contact the Los Angeles Department of Building and Safety to verify what applies to your project. The same division of labor protects you: each professional is trained and accountable for their own expertise, and no one crosses into work they are not qualified to do. When you call a carpenter, you get carpentry. When you need an engineer, you hire one. When insects are present, a pest operator treats them. This clarity is how homes get repaired right.