InspectAPedia ^®

How to Clean Mold on Building Framing Lumber or Plywood Sheathing and Use of Fungicidal Sealants on Wood Building Materials - Mold Cleaning Mistakes to Avoid MoldAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com

• Mold Cleaning Mistakes to Avoid when cleaning Mold on Building Framing Lumber or Plywood Sheathing
• Advice on How to Use of Fungicidal Sealants on Wood Building Materials

This section of our "How to Clean Mold" article describes common mistakes people make when attempting to clean up mold. Avoiding these mold cleanup errors can save you money and may also avoid dangerous side effects of bleach, mold chemicals, or ozone when improperly applied.

This article offers advice on cleaning mold found on surfaces of un-finished wooden building materials such as framing lumber (rafters, floor joists, wall studs), and building roof, wall, and floor sheathing such as plywood, tongue-and groove pine boards, and other structural wood surfaces in buildings. We discuss the pros and cons of using fungicidal sealants and bleach on wood surfaces and give sources and list types of those products. We also discuss common errors made when cleaning wood surfaces, such as relying on bleach or performing expensive and unnecessary cleaning on cosmetic black mold on wood surfaces. © Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use the links at page left to navigate this document or to go to Other Resources.

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

4. MOLD CLEANING MISTAKES people make when cleaning-up moldy building materials and moldy surfaces

This discussion lists common mold remediation or mold cleanup errors specific to attempts to clean mold from contaminated framing lumber or building sheathing such as plywood or pine boards used for subfloors or roofs. Inadequate cleaning and cross contamination are the two most common mistakes we find when inspecting and testing sites to perform a post remediation clearance for mold cleanup. Using bleaches, sprays, or ozone instead of cleaning are close behind in frequency of mistakes. Other mold remediation errors such as performing only demolition and failing to clean up the dust and debris caused by that step, are important but are not discussed in this moldy wood cleaning document.

Mold Cleanup Workmanship, Procedures, & Asbestos: But before discussing these (below) we add that you should be alert for other building contaminants that might need attention and which can be most-economically addressed by combining them into the mold remediation project. A common example is the discovery of asbestos pipe or surface insulation in a building which because of its location or condition needs to be encapsulated or removed. Since the technology for mold remediation involves similar containment and cleaning standards, if you have an asbestos problem at a different area on a moldy building you should discuss adding that work to the job. If asbestos materials are in the mold-remediation area and will be disturbed by the mold cleanup process, removing and cleaning this material will probably be unavoidable and will, unfortunately, add to the cost of the job.

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

CROSS CONTAMINATION - Be sure to protect from mold spore cross contamination of other areas when cleaning up mold

Protect the areas outside or around the one being cleaned from mold contamination by following published mold remediation guidelines such as the NY City Mold Cleanup guidelines. For large products (more than 30 sq.ft. of contaminated contiguous surface), the procedure involves tenting or sealing off the work area using plastic barriers, combined with establishing negative air pressure inside the work area so that particles and dust do not tend to escape the work area.

It is important that you protect workers performing remediation using appropriate masks, clothing, etc. Occupants, particularly people at extra risk of mold-related illness should not perform nor be present during this work.

Don't spray or power-wash moldy wood or other moldy surfaces without proper containment as you may be simply spreading mold spores around the indoor environment where you will infect other materials.

Small work projects (less than 30 sq.ft.) can normally be handled as a simple building cleaning or renovation project. But during a "small project" you should remain alert for the discovery of a previously unrecognized large area of contaminated materials. If the small project discovers that it has become a large one, work should stop to permit set-up of proper dust and particle containment.

More Reading:
Mold Remediation & Cleanup Standards
Mold Levels: allergenic or toxic mold: how much means a problem
Mold Cleaning, Remediation, & Clearance Testing Standards list of documents

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

USING BLEACH - Bleach as a "Mold Medicine" to try to kill mold or prevent mold in buildings

Bleach, diluted bleach, or bleach sprays used in cleaning may be appealing but they are unnecessary, potentially dangerous (if you get bleach in your eyes), and the use of bleach tends to lead to improper and inadequate cleaning - if you substitute "spraying bleach" for actually cleaning or removing the mold your cleanup will not be successful.

The object of mold remediation is to clean, or remove, the majority of the mold particles (spores, conidiophores, hyphae, mycelia) from the target surface. The operative word to fix in mind is to "clean" or "remove" the problem mold. "Killing" the mold is not the object - first of all because my lab work shows that you're unlikely to kill all of the mold on a surface using bleach, unless you use it at a concentration and duration which is so strong that you're likely to completely destroy the "bleached" material, and second of all because even if you could "kill" every mold spore, you are at risk of leaving toxic or allergenic particles in place - they may be dead but still toxic.

Finally, "mold removal" only works if you're cleaning a relatively hard, non-porous surface such as finished wood, painted metal, or plastic. Soft materials like Sheetrock(TM) or drywall which have become moldy generally should be removed, the exposed surfaces cleaned, and then new drywall can be installed (after you've also corrected the reason for the mold growth in the first place).

Spraying anything if spraying of fungicides or sealants is to be used in place of actual cleaning or removal of mold is an improper and inadequate practice which risks leaving a reservoir of toxic or allergenic particles in the building.

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

USING OZONE - to "Kill" mold to "remove" or prevent mold in buildings

Ozone Generators are another futile attempt to "kill" mold instead of cleaning it up. This "magic bullet" approach does not work and can destroy some building materials as well as the health of building occupants. Because of the trouble and cost of performing an effective mold cleanup in buildings, some vendors offer what sounds like an attractive alternative, offering to "kill all building mold" using ozone. One Midwest company offers to tent the building and follow a mold extermination procedure.

As with the "bleach" and other "kill the mold" approaches we described above, this process fails to remove the problem reservoir from the building, leaving toxic or allergenic particles.

One of our clients, in an effort to remove odor and mold problems from their building, rented a commercial ozone generator ran it aggressively in closed rooms in their home.

The ensuing odors, which we tested and traced to oxidized carpet padding, were so severe that the building was no longer habitable. Carpeting had to be removed as well as other oxidized rubber and foam products which had been "ozone treated."

Worse, the underlying cause of the original complaint, which we traced to a history of flooding basement and wet building materials there, had gone unrecognized and still needed to be addressed.

There are valid applications of ozone as a disinfectant but it is not a valid treatment for mold in buildings.

More Reading:
The Use of Ozone Generators Indoors for Control of Odors and Mold Removal in Buildings: A Summary of Hazards and False Claims

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

PREVENT FUTURE MOLD - Failure to Prevent future mold growth wastes mold cleanup dollars

How Much Mold Must Be Removed - How Clean Do Surfaces Need to Be?

Following a proper mold cleanup, if there is a future mold problem in a building it is unlikely to be due to having left behind an "inoculation" of problem mold. The standard for physical removal of moldy debris varies by material. For drywall we remove all visibly moldy material and continue removing drywall to no less than the next adjacent stud, rafter, or joist. For insulation which has been wet, we remove all suspect insulation and all insulation within 24" of the suspect material. However if moldy and wet conditions were long-standing in a building, removal of all of the insulation may be necessary. Generally it is less costly to remove and discard more material than to "finish" the job and then discover that it needs to be done over again because the initial work was insufficient.

Does the building need to be sterile? Is the object to reach a mold spore count level of zero?

No washing, sanding, scraping, or other surface cleaning will remove all mold spores from wood where mold was previously found. It is unlikely that most construction materials, even when new, are free of mold spores, nor is "zero mold" a reasonable nor possible objective. Cleaning moldy framing lumber followed by application of a sealant may be the most cost effective alternative (where removal of the lumber is cost-prohibitive or otherwise not possible). While lumber replacement with apparently "clean" new lumber may sound appealing, it is likely to be cost prohibitive and in fact may include its own mold when it is unloaded at the work site.

Unless framing lumber has been actually damaged, such as by rot, replacing it due to mold contamination is not justified and would be improper.

Key Steps in Preventing a Return of Mold Problems After a Mold Cleanup Project

Prevention of water leaks or excess humidity in building interiors, including wall and floor cavities, is critical if you want to avoid a mold growth problem in a building. Even following the most thorough mold remediation, future roof, plumbing, or cooling condensate leaks or any other source of water entry all risk future mold growth and related cosmetic, structural, health problems and economic costs.

More Reading:
What indoor humidity should we maintain in order to avoid a mold problem?
MOLD PREVENTION GUIDE: Correct the Causes of Mold and Prevent Indoor Mold or other indoor environment problems
Mold Prevention: Avoiding Mold Problems in Buildings by Using Mold-resistant Construction Products & Practices
Priorities for Preventing Indoor Mold Contamination in Buildings - responding to leaks and floods

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

COSMETIC MOLDS - Avoid unnecessary & expensive "black mold" cleanup projects for cosmetic molds and stains

It's important to distinguish cosmetic Ceratocystis, blue stain mold, blue rot, from other problem molds which in fact might be "toxic black mold" such as Stachybotrys chartarum or harder to spot but often more problematic molds in buildings such as the Penicillium sp. and Aspergillus sp. families of molds. One of our clients had begun a $600,000. "mold remediation" project on their home.

A careful investigation of the property found that all of the "black mold" which had frightened the owners and which had resulted in this expensive cleaning contract, was cosmetic "blue stain" mold which had been present on the lumber since the day of construction of the building. The mold was of no concern other than a cosmetic one. Other clients occasionally send "not mold" samples to our laboratory.

To be sure you're not incurring a big and unnecessary expense, be sure that the "mold" to be addressed is really mold, and further, that it's not just a cosmetic mold, read the articles below before undertaking a costly mold remediation project.

More Reading:
Stuff that is Not Mold,
Molds that are Harmless - Cosmetic
Mold Levels: allergenic or toxic mold: how much means a problem

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

More Information on Building Diagnostic Inspections and Repairs

• Action Guide for Mold: what do I do about mold in my home? Step by step instructions.
• Humidity: What indoor humidity should we maintain in order to avoid a mold problem?
• Mold Levels: allergenic or toxic mold: how much means a problem
• Not Mold, Stuff that is harmless or cosmetic-only
• Ozone Generators Indoors, The Use of for Control of Odors and Mold Removal in Buildings: A Summary of Hazards and False Claims
• Prevention: Avoiding Mold Problems in Buildings by Using Mold-resistant Construction Products & Practices
• Prevention of Mold list of articles on how to Correct the Causes of Mold and Prevent Indoor Mold or other indoor environment problems
• Standards: Mold Cleaning, Remediation, & Clearance Testing Standards list of documents

InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

Building Inspection, Problem Diagnosis, Forensic Investigation & Testing, Repair Consulting

Contact Daniel Friedman for website content suggestions or for fee-paid consulting

	Enter your search termsSubmit search form
	Search InspectAPedia.com