Surface growth versus decay
Mold and rot are related but not the same. Mold lives on the surface; decay fungi break down the wood itself.
Surface mold
- Spotting or fuzz that wipes or brushes off the face
- Wood is hard when probed with a screwdriver
- Normally cleaned in place, then dried
Decay or rot
- Wood is soft, stringy, cracked into cubes or crumbly
- A screwdriver sinks in easily
- Usually needs structural repair, sistering or replacement
How framing is normally cleaned
On sound lumber, the goal is to physically remove growth, not to bleach it or cover it. Common methods are HEPA vacuuming, wire brushing, sanding, and in larger crawlspaces, abrasive blasting with materials such as soda or dry ice. Each produces dust, which is why the work happens inside containment with air filtration running.
Some staining can remain after cleaning, especially on older lumber. Light staining on clean, dry wood is not the same as active growth. Coatings and sealers are sometimes applied afterward, but they are meant to go on wood that has already been cleaned and dried, not as a substitute for cleaning.
In Wheat Ridge, the framing question comes up most often under ranch homes where crawlspace joists have sat in humid air for decades, and in basements where a bottom plate sat in floodwater. Old-growth lumber in many mid-century houses is dense and tends to clean up well. Bottom plates resting directly on a damp slab, and rim joists behind leaky window wells, are the pieces most likely to be soft enough to need replacing.
Factors that push toward replacement
| Factor | Cleaning usually works | Replacement more likely |
|---|---|---|
| Firmness | Hard, sound wood | Soft, crumbling or delaminated |
| Material | Solid sawn lumber | Particleboard or water-swollen OSB |
| Moisture history | Wet once, then dried | Wet repeatedly for years |
| Location | Accessible faces | Inside layered assemblies that cannot be reached |
| Structure | No sag or cracking | Sagging floors or cracked joists |
Questions to settle before framing is treated
- Was each affected member probed for soundness, and which ones were soft?
- What cleaning method will be used, and what will the wood look like afterward?
- What moisture reading must the wood reach before it is closed up or coated?
- If a joist needs repair, who designs and performs it, and does it require a permit?
- Is any coating being used, and why?
General information for Wheat Ridge, not a quote or professional advice. In an emergency, call 911.