Wet wood, rotten wood and mouldy wood

What wet means for a piece of wood

Moisture in wood has a unit. The Canadian Wood Council defines moisture content as the weight of the water in a piece of wood divided by the weight of that wood oven dry, written as a percentage. The figure can pass 100%. The Wood Council's own example is 200%, a piece carrying twice as much of its weight in water as in wood.

The Wood Council names two numbers to remember on that scale. It calls wood dry at 19% moisture content or less, and it puts fibre saturation, the point where the cell walls hold as much water as they can, at an average of around 28%. Dry lumber, stamped S-DRY or KD, has a moisture content no greater than 19%, and wood used indoors eventually stabilizes at 8 to 14%.

Wet is therefore a reading, and a high one is not yet decay. The Wood Council says wood can safely absorb large quantities of water before it reaches moisture levels that invite decay fungi. When a crew's drying log records a percentage for a joist or a stud, these are the lines to read it against.

Mould and rot answer to different triggers

Mould is counted in hours. Desa Contracting's Toronto guide says mould can start growing within 24 to 48 hours, and CPR24 Restoration, also in Toronto, says it can begin to develop within 24 to 48 hours after water exposure. Ultimate Mold Crew says the risk depends on how long materials stayed wet, humidity, temperature, airflow and material type, and that it increases when drywall, insulation, wood or flooring remain damp.

Rot is wood decay, and the Canadian Wood Council ties decay to a moisture line rather than a clock. Decay fungi need an accessible source of water, it explains, and the accessible water in wood is the free water that fills the cell cavities once the cell walls are full. So decay can generally only start while the wood is above fibre saturation, which averages around 28%. The page puts no number of days on it.

Desa Contracting's timeline does put a time on the structure. It says structural damage can start within 72 hours, without saying what kind. Ultimate Mold Crew's worked example of a long-wet case is a slow leak behind a wall that goes unnoticed for weeks or months, with drywall, insulation, framing and flooring edges affected. It estimates that job at $3,000 to $12,000 or more, and says long-term leaks are often more expensive than sudden ones because they create hidden mould and material damage.

How a crew sorts what dries and what leaves

The sort runs material by material. Desa Contracting's guide says some materials can be dried and restored while others must be removed and replaced, and it names structural framing among the materials a crew evaluates, next to flooring, drywall and insulation, baseboards, cabinets, concrete and electrical systems. Ultimate Mold Crew's list runs the same way. It says concrete may dry with equipment, drywall may need partial removal, insulation may need replacement, laminate flooring may swell, and cabinets made from MDF or particleboard may break down after soaking.

For floors the firm is specific. Its flooring notes say hardwood can cup, warp or require refinishing, laminate often swells and needs replacement, and a subfloor can require drying, repair or replacement. Drywall gets a conditional answer. Ultimate Mold Crew says it may be dried if the damage is minor and the water was clean, and that removal is more likely when it is saturated, contaminated, damaged, mouldy or wet inside a wall cavity.

Drying in place does not leave wood unchanged. The Canadian Wood Council says wood shrinks and swells only when its moisture content changes below fibre saturation, and that it does most of its shrinking as it drops from 28 to 19%. Drying can open cracks called checks, where the dry outer shell shrinks against a wetter core, and it can warp a piece, because wood shrinks by different amounts in different directions. A member that stays in place can still move as it dries.

Contamination changes the sort. On a sewage or drain backup, Ultimate Mold Crew says, porous materials often cannot be safely dried and reused, and the discard rules are set out in what has to be thrown out after sewage.

Why the meter decides when wood is dry

As a piece of wood dries, the Canadian Wood Council says, it develops a moisture gradient across its section, dry on the outside and wet on the inside. The surface is the first part to dry, so a dry feel says little about the core. Ultimate Mold Crew makes the same point about household fans, which it says may dry the surface while moisture remains trapped behind walls, under flooring or inside insulation. It also says basements are more likely to need moisture monitoring because concrete, framing, insulation and flooring systems can hold water longer than homeowners expect.

Published drying times come as ranges. Restoration Professionals, which works across Toronto and the GTA, says most structural drying takes three to five days, verified by moisture readings rather than time alone. CPR24 Restoration gives hardwood a longer range. It says hardwood floors and furniture can take up to a week or longer to dry thoroughly. The rest of the phase is set out in how long a basement dry-out really takes.

A reading on its own has a published price. Ultimate Mold Crew lists an inspection or moisture assessment, covering a visual inspection, moisture readings and a review of the source, at $200 to $500. Its questions to ask before hiring include whether moisture readings are included and how many days the equipment will run. Among its red flags are a contractor who replaces drywall before confirming drying and one who says everything can be dried without checking wall cavities.

What each outcome costs on Toronto price lists

Drying is priced as its own line. Desa Contracting's Toronto guide prices industrial drying with fans and dehumidifiers at $800 to $4,000 per job, and says drying takes two to five days for most homes and condos. Ultimate Mold Crew says the price of structural drying depends on the number of air movers, dehumidifiers, drying days and moisture-monitoring visits.

Removal and replacement are separate lines on the same Desa list. It prices material removal (drywall, flooring) at $500 to $3,000, drywall removal and replacement at $300 to $1,200, laminate flooring replacement at $800 to $2,500, and hardwood floor drying or replacement as a single line at $2,000 to $8,000. Because the hardwood line joins the two outcomes, it does not say which one sits at which end of the range.

Mould and rebuild are separate lines again. Ultimate Mold Crew says mould remediation may be a separate line item or a separate scope, and prices it after water damage at $1,500 to $6,000 or more, depending on the affected area, material type and containment needs. Desa Contracting prices a complete rebuild or reconstruction at $1,000 to $20,000 or more. The full Toronto ranges sit on the water damage restoration cost and mould removal cost pages.

Rot is the outcome no price list names

None of the price rows behind this site's cost pages names rot, decay or framing repair. The lists price drying, removal, mould remediation and rebuild. None of them prices the discovery that a joist end has gone soft. The nearest published lines describe other work. Ideal Response, an Ontario restoration firm, has a line called structural repairs at $2,000 to $10,000 or more, and describes it as replacing drywall, flooring, baseboards and insulation after water removal. Desa Contracting's guide puts structural reinforcement in its repairs and reconstruction step, with no price beside it.

A soft joist is therefore a change of scope rather than a line item, and none of the price lists this site draws on publishes a figure for one. Ultimate Mold Crew's questions to ask before hiring include what happens if more damage is found after demolition. That answer is worth having in writing before the wall is opened.

Rot also appears in policy wording. Mitch Insurance Brokers, an Ontario brokerage, says mould, fungus or wet rot is typically not covered, though some insurers may cover mould if it is the result of a covered loss. Its exception names mould, not rot. Which water losses a standard Ontario policy covers in the first place is set out in does Ontario insurance cover a flooded basement.

What the index records about who does this work

Of the 294 companies in this index, 258 are listed under Water Damage Restoration and 200 under Mold Removal, and 175 carry both. That overlap is what matters when a drying job turns into a mould job, as stopping mould after the water is gone sets out.

Framing work is a building trade, and few records carry that label. Google gives 4 of the 294 records the label general contractor, 2 construction company and 2 remodeler, against 211 labelled water damage restoration service. Who should run a rebuild is compared in restoration company or general contractor.

The records hold no field for drying equipment, moisture logs, the standard a firm works to or technician certification, and Ontario licenses nobody for mould removal. Google ratings sit on 277 of the 294 records, with a mean of 4.76, which says nothing about how a firm reads a moisture meter. A profile carries the hours the firm posts, its public Google review record and a quote request.