FAQs on the proper way to clean up mold-contaminated wood or wood surfaces:
Questions & answers about how to remove mold from wood or wood surfaces in or on buildings.
This article series 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.
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The object in cleaning mold from a wood surface is to remove all fungal material from the surface of the wood: fungal spores, hyphae, and conidiophores (the spore producing structures of mold). It is not necessary to remove all stains from wood.
These questions & answers about the proper procedures & methods to clean moldy wood surfaces in, on or around buildings were posted originally at MOLD CLEANUP - WOOD FRAMING & PLYWOOD
On 2017-07-25 by (mod) adding link to warnings about relying on bleach for mold remediation
Thank you for pointing out my error and omission, Karen. I will fix the article above.
Meanwhile please take a look at MOLD CLEANUP, BLEACH - http://inspectapedia.com/mold/Bleach_Mold_Contamination.php where the concerns with relying on bleach or any other "mold killing" approach are explained.
Let me know what you think of that article and let me know what questions remain and I'll be glad to pursue those further.
On 2017-07-25 by Karen Vargas
the article said see our warnings about using bleach but I couldn't find the info
On 2017-03-27 by (mod) Photos show extensive mold on numerous surfaces including drywall that will have to be remove
Photos show extensive mold on numerous surfaces including drywall that will have to be removed - such moldy soft- or paper-based materials can not be cleaned.
On 2017-03-27 by Ash Sinclair
Thank you very much for such a speedy and informative response Mr F. I've sent you and email with a number of photos of the wendy house. Its dry in there now. Look forward to hearing your verdict on whether this is a dangerous mould.
On 2017-03-26 by (mod) - danger of black spots in child's Wendy house
First I'd want to know that the problem is mold vs. something else, since cleaning requirements may be different for not-mould.
You're welcome to use the page top or bottom CONTACT link to send us photos for comment.
I would NOT sand the surfaces in most cases as that's a huge amount of work and makes a dusty mouldy mess, though that can be appropriate for some wood surfaces.
Use the search box just above to
Search InspectApedia for HOW TO CLEAN UP MOLD
and also search for
FUNGICIDAL SPRAY & SEALANT USE GUIDE to read about the sealant you're asking about. Basically, clean moldy surfaces, when dry, depending on the area and use and material, it can make sense to spray with a sealant - that isolates a few remaing spores and more important seals the wood against future moisture uptake - thus reducing the attractive of those surfaces to mold growth.
Be SURE you find and fix the causes of high indoor moisture or leaks.
On 2017-03-26 by Ash Sinclair
We've just opened up our childs wendy house after it being closed all winter and it is covered internally with black spots - black spot mould? Any idea how to make it safe / clean for the kids to play in. Ideally we hoped to paint it this spring in internal white emulsion.
Any tips on how we get rid of any danger from the mould and how we can prep the wood surface (its semi rough) for painting? My dad suggested sanding it but I think from your blurb above that would risk spreading the mould and I also worry about toxicity for dad and kids. Thanks in advance for your advice.
On 2016-09-21 by (mod) If the area stays dry it won't invite mold growth.
Not much, no. If the area stays dry it won't invite mold growth. If the mold reservoir itself was cleaned off - removed, then that's enough.
On 2016-09-20 by Den
A leak in a pipe joint beneath my stairs went unnoticed for some months. The drywall and insulation were soaked, have been discarded.
Mold was mostly on the outer surface though some specks were seen inside, on the brick wall behind. The light framing onto which the drywall was nailed seems sturdy and had been washed with bleach. I think I am good to go, re-insulating and re-installing drywall. Pipe joint is fixed. Should I be concerned about mold growing back inside the wall?
On 2016-05-02 by Anonymous
I have an outdoor storage shed with mold inside on all the walls, door, ceiling. I plan to use my pressure washer to clean it then let it dry out for a few days then put it up for sale as I am selling my property and the new owner does not want the shed. What do I need to know and what type of safety wear do you recommend? thanks in advance
On 2016-01-27 by Sammi
HI, i have thin laminate flooring down over the wooden boards in my bathroom. Last week i noticed the toilet has been leaking slightly, so i put a towel under it and called my landlord.
Its a week down the line and noone has turned up to fix the toilet, so its still leaking and drenching the towels i put down. Today i lifted the laminate up and was so shocked to discover most of the wooden flooring has turned a milky white/blue and some of it has turned fully black. I wish i could post a picture its really awful. I presume this is from moisture trapped between the laminate and the wooden floor from the leaking toilet.... Any advice on the CHEAPEST and QUICKEST way to fix this would really be appreciated , thanks guys :) x
On 2015-12-01 by (mod) how to safely get rid of mold contamination in a fixer-upper house
Use any household cleaner - or if there is more than 30 sqft of contiguous moldy surface, hire a professional mold cleaning company; the proper approach is to remove the mold and fix the leak or moisture problem that caused its growth.
If you cannot afford a professional you may be tempted to do the cleanup yourself - there are several articles here on how to clean up or remove mold from building surfaces; but keep in mind that if you don't proceed properly (containment of airborne dust, personal protective gear, proper cleaning procedures) the risk is that you make yourself sick or spread moldy dust to other house areas - if those problems occur the ultimate cost is greater than if a pro did the work properly the first time.
Check with your local community aid associations to see if you can get some financial help.
I would NOT move into a moldy home before I knew if I were risking not just health issues but contamination of my stuff; If the mold is ONLY in the basement, keeping that area under negative air pressure with respect to the rest of the home (fans blowing out) can help.
On 2015-11-30 by Anonymous
I just bought a fixer upper house and there is white mold well it appears as white mold on the support beams in the basement/crawlspace
i need help i dont know if its safe or how to get rid of it. I have 2 kids and i have to be able to move in very soon. Help please. I cant call a professional because i dont have money and i dont know if my house would get condemned.
On 2015-11-18 by (mod) clean white mold off of cabin floor joists over a crawl area
Thank you for the question, Ann.
Use the page bottom CONTACT link to send some pictures of the problem if you can, including a sharp closeup.
If the area is now dry and the mold light and cleaning difficult and no IAQ complaints are voiced in the living area I would cover the wood surfaces in the crawl with a fungicidal sealant. A pro might spray a sanitizing treatment furst, then let that dry before sealing.
On 2015-11-17 by Ann F
have spent quite a bit of time reading articles and can't seem to find the specific answer I am looking for. We have a cabin in upper penninsula Michigan and have noticed white mold growing on the floor joists in the crawl space. I believe this used to be very damp in the past but with the efforts of a past owner as well as ourselves, it is very dry.
We installed thick plastic over the sand floor to stop moisture evaporating upward and that has worked very well. It is an uninsulated cabin with no drywall. There is no moldy smell even when in close proximity to the "white Mold". The floor joists are made of rough cut wood, so wiping them is out of the question. I noticed that the mold is growing along the grain lines of the wood.
I fear that disturbing it in the attempt to remove it will make a bigger mess than just leaving it alone. The cabin was built in the 1950/60's era as a summer resort cabin. It has been observed that it may not have even been on a foundation when first constructed. As I said there is no moldy smell when entering the crawl space and it is a very dry space at this time.
So, white mold on rough cut floor joists-should we worry about it? This cabin is closed down/no heat for the winter.Thank you so much!
On 2015-11-17 by (mod) clean or remove mold on upholstered furniture? doubtful
Upholstered furniture is just about impossible to clean of mold if it was actually supporting mold growth. It'd have to be stripped to the frame; no vacuuming or treatment can get into multi-inch-thick padding &c.
If mold was on a wood surface, clean it with any household cleaner; If you like you can then seal the cleaned but non-visible surfaces with a clear lacquer.
On 2015-11-17 by Joyce
We had a roof leak that left mold on the wall and floor of the bedroom. My wood furniture and bed smells musty.
I can wipe off the tops of the furniture but the backs and underneath are made of a porous wood that I'm not sure what to clean them with.
On 2015-10-23 by (mod) wet or moldy plywood under leaky bath tub - mold killing primer?
If the plywood doesn't need to be replaced for structural reasons, physically clean the surfaces, don't worry about stains that remain (They're of cosmetic import), or for extra confidence seal the cleaned dry surfaces with a fungicidal sealant paint. Search inspectapedia for fungicidal sealant to read details.
See FUNGICIDAL SPRAY & SEALANT USE GUIDE - sprays and sealants used after proper cleaning reduce further risks
On 2015-10-23 by Amelia
I found a leak in front of my tub, where the access panel is. It's coming from the drain. My concern is the wet plywood underneath.
I have had a fan blowing on it for about 1 day and have wiped off the surface with bleach ( before I read these articles). Any suggestions on what to do next? I hope to avoid having to replace the plywood as there is little damage. My main concern is to get rid of the mold. Leak has been fixed.
On 2015-10-08 by sharon
I am having some mold issue on the plywood flooring. can I use mold killing primer.
On 2015-08-21 by Pierre
We pulled cupboards and wall paneling off the main(lower) floor and found an old leak in the ABS drain. The horizontal wood boards nailed across the studs look like charred wood! They actually look and feel like they were totally charred with at least a few inches of wood partially burned away. What kind of mould would make the wood look like that? Is there a danger of it being black mold?
Thanks for your help!
On 2015-10-23 by (mod) - moldy attic rafters, black and white - is there a difference in removal methods?
Nope. The mold genera/species does not change the appropriate mold cleanup and prevention methods, with the exceptions that
1. some dark colored mold is harmless, only cosmetic, and that case is easy to identify - see BLACK COSMETIC MOLD
2. large areas of mold should be cleaned up by a professional, typically that's more than 30 sq.ft. of contiguous moldy surface
3. small areas of mold can be cleaned by most people using ordinary household cleaners
On 2015-07-18 by Anonymous
Excellent information on this site. My question is: I have mold in my attic on several rafters. The leak has been repaired, but the mold hasn't been dealt with. I see black and white mold. Is there a difference in removing this, and can I use a cleaning solution on both? I do plan on using a fungicide sealer after wiping down.
(Feb 13, 2014) Karen Gunderson said:
Question: The heat pump is on a wood stand. Some water leaked and the wood got wet. There is black color on the wood around the bottom. It has been tested for mold, and mold was found. Have cleaned the wet carpet out, scrubbed cement with Clorox bleach. removed most everything that was in the storage area.
Am replacing the material around the wood stand, but wonder if I should do something more, like seal the bottom of the four boards. Do not want mold inspection to come back positive.
Should I try to get all the black stuff off the boards. Could I spray the foam on the boards so nothing could get through from boards?
If water ran beneath an enclosed wood base it's possible that the hidden underside is mold contaminated. If that area is inaccessible, I'd leave it alone, arguing that the total size of moldy area is trivial; but I agree that after cleaning, when the stained wood surfaces are dry, if you seal those with a paint (or if you prefer a fungicidal sealant paint) you'll reduce the moisture uptake of the wood and thus improve its mold-resistance in the future.
Spray foam on exposed wood outdoors sounds like a mess and one that may trap water; and indoors we don't like to leave foam exposed - that's a fire hazard.
see MOLD CLEANUP, BLEACH - not an adequate mold remediation approach
(Aug 16, 2014) E H said:
I have a interior 2 x 4 stud walls that have mold spots on them. What is the best way to kill it or do I need to remove the studs?
You do not need to replace moldy wood framing studs.
If you want to deal with mold on the studs, physically clean the surfaces and to be thorough, when dry, paint them with a lacquer primer sealer.
The object when dealing with mold contamination is to remove it, not "kill it" - some dead spores remain harmful.
You also want to identify and fix the cause of mold growth.
(Sept 20, 2014) Kirt said:
We have recently discovered that the builder of our home did not use window sill flashing, and the installation Tyvek was done in such a manner that it does not shed water - it catches it. As a result, there is dry rot and what appears to be black mold in the sheathing. How much sheathing ought to be removed - a 12" band all around, or what? thanks,
(Sept 29, 2014) Stacey said:
We are replacing the laminate flooring in our bathroom and noticed black mold near our tub on the plywood underneath the laminate we pulled up. First, what is the best way to clean this mold if we can do it ourselves and second, should we be concerned about any thing growing under the tub?
Oct 6, 2014) Nancy Collins said:
I went into attic and noticed at top of attic stairs on rafters on each side it looks like white paint spayed. It's hard like paint and doesn't flake or and it's not fluffy. Could this be mold. Thanks
Nancy use our email found at CONTACT found at page bottom to send us some photos and we can comment on what you are seeing
(Dec 11, 2014) James said:
I had a new roof put onto the house. I had them remove a sky-light over the bathroom. My contractor was supposed to have close off the area in the ceiling to the new sheeting, but he bailed on me.
Now I have what appears to be mold on the sheeting from moisture from showering. I have inspected the attic and the mold is contained to only the area where the sky-light was removed. the opening is framed and drywalled to the rafters. What would be my best solution for cleaning this before I close it up? Thank you
Fix any leaks
Physically clean the wood surfaces using any household cleaner and a scrubby sponge - don't get moldy water or cleaners in your face or eyes.
Optionally: after the cleaned surfaces are thoroughly dry use a fungicidal sealant
(Mar 27, 2015) Denis said:
I had a roof leak that allowed water into the attic affecting the an area of insulation, roof rafters along with a 12x18 bedroom ceiling.
My question is, does sanding the affected roof rafters and removing all of the attic insulation the correct process? Why sand? Why not wipe down the affected wood structures.
There is no requirement for sanding to remove mold; you can scrub or wipe off moldy surfaces with cleaning products but you will probably want to treat the dried surfaces with a fungicidal sealant as well. In fact the cost of sanding for mold remediation is rather questionable except where it is needed for cosmetic reasons such as perhaps leaving an exposed beam in a living space.
(May 21, 2015) Mr.justincox said:
Recently noticed my floor and sub floor in my bathroom are completely saturated and black(some black mold as well), very easily removable,
my question is one of the joist is visible rotten on the surface and a Flathead screw driver easily penetrates about 1/4 of the surface.
Can the rot be removed and reused or does it need to be removed and replaced? Along that same line the plywood sub floor that's leading under the wall is also noticeable rotten and needs to be addressed, how do I asses this and what can been done?
I have pictures if that would help?
Yes I'll comment when I've seen the photos.
Continue reading at MOLD CLEANUP - WOOD FRAMING & PLYWOOD, topic home, or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or see MOLD CLEANUP - WOOD FLOORING
Or see BLACK COSMETIC MOLD - not all black mold is harmful
Or see FUNGICIDAL SPRAY & SEALANT USE GUIDE - sprays and sealants used after proper cleaning reduce further risks
Or see MOLD CLEANUP, BLEACH - not an adequate mold remediation approach
Or see MOLD CLEANUP - WOOD FLOORING - how to remove mold from wood flooring surfaces
Or see MOLD REMOVAL, MEDIA BLASTING - good approach for irregular or hard-to-clean surfaces
Or see SIDING, WOOD CLEANERS, STAINS, PAINTS how to remove stains on siding & how to choose the proper paint or stain coating
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