# Wet Floor Joists



## scotte1975 (Feb 3, 2012)

I recently discovered a leak under my dishwasher. I think I caught it pretty soon because i only had to about 50 sq ft of subfloor damaged. I decided to pull the subfloor and ServPro was finished drying it (4 DAYS). Now that I have the subfloor up I have noticed that my floor joists are wet. Is there anything I can do or do I just need to call ServPro back out to dry the joists. Thankfully I live in SC and we are having a VERY mild winter.....(knock on wood)


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## Daniel Holzman (Mar 10, 2009)

Those joists look pretty moldy. I would treat them with bleach, then let them air dry for a few days. No need to get Servpro back out, unless you are in a big hurry to dry the joists. Doesn't look like there was any structural damage, just get rid of the mold, let them dry, then repair.


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## jasin (Jan 22, 2012)

The joists themselves look to be structurally sound. They just have lots of mold on them. I would not try to remove the mold yourself though as you could mess up the integrity of the wood. You should call a mold abatement team to come out and remove it. They can remove it by spraying it off with dry ice.


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## jasin (Jan 22, 2012)

Do NOT need hangers. Joists are resting on the sill.


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## jasin (Jan 22, 2012)

I noticed as well, that you have a sheet of osb. I hope you are not using that for your sub-flooring. Osb is not made for sub-flooring!


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## woodman58 (Aug 22, 2010)

In most areas OSB is an acceptable subfloor. I live in the midwest and it has been used for years with no problems. Just use bleach as Daniel said. It will kill the mold.


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## joecaption (Nov 30, 2011)

Your being given the wrong info.
There's no way anyone here from a picture can tell you those joist are fine. Someone there on site is going to have to poke around and see how deep the rot is.

No mold control company I've ever heard of would suggest using bleach to treat black mold on wood like that. There going to treat it with one form or another of Boric Acid. It kills the mold and stops it from coming back.

One poster gave you info on the wrong joist hanger to use. It would be one that looks like this. (Just make sure there the right hight for the joist you have.)
http://strongtie.com/products/connectors/LUS-HUS.asp

Then they misinformed you that OSB should not be used as a subfloor, wrong again. Only have a picture to go by but that subfloor you have looks like Advantec. OSB and Advantec as long as there 3/4" thick will work fine and has been used in millions of homes all over the world so I'm not sure where they came up with that idea.


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## jasin (Jan 22, 2012)

woodman58 said:


> In most areas OSB is an acceptable subfloor. I live in the midwest and it has been used for years with no problems. Just use bleach as Daniel said. It will kill the mold.


The National Tile Contractors Association recommends that OSB NOT be used as subfloor.


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## jasin (Jan 22, 2012)

joecaption said:


> There's no way anyone here from a picture can tell you those joist are fine.


If it were not structurally sound it would be cracked, sagging, warped, twisted, etc.. something. We do not see any of that though nor is there any indications there is any of that.


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## jasin (Jan 22, 2012)

joecaption said:


> No mold control company I've ever heard of would suggest using bleach to treat black mold on wood like that.


:thumbsup: I agree, avoid using bleach.


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## jasin (Jan 22, 2012)

joecaption said:


> There going to treat it with one form or another of Boric Acid. It kills the mold and stops it from coming back.


"Dry ice blast cleaning is quickly establishing itself as a favored method of cleaning in mold remediation (mold removal). Dry ice blasting is superior to cleaning mold compared to traditional labor-intensive techniques such as sanders, scrapers and wire brushes. The dry ice process cleans as thoroughly or more so and in dramatically less time. Also, compared to soda blasting, dry ice blast cleaning is as fast and creates far less mess." (Association for Facilities Engineering)


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## oh'mike (Sep 18, 2009)

Hangers are not needed as the floor joists are sitting on a sill plate---No idea where that idea came from.

OSB is the most common subfloor in use today---Don't know what citation that came from either--

TCNA (tile council) book sites the use of OSB under tile---another idea without any real world experience--

Sorry about the bad info---You will find good info here along with some very weak info from a new member.


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## joecaption (Nov 30, 2011)

Look again at the top of the floor joist, looks all punky to me.
Fungus eats the cellulose holding the wood fibers together causing the wood to become soft.
Fungus eaten wood does not do any of the things your suggesting to look for. It just falls apart.
I've seen it so bad I could snap off whole sections with my bare hands.

What would make you think there was tile on that floor? 
Even of there was tile going to be laid you simply go over the floor with 1/2 subfloor rated plywood. Done all the time.


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## jasin (Jan 22, 2012)

joecaption said:


> Then they misinformed you that OSB should not be used as a subfloor, wrong again. Only have a picture to go by but that subfloor you have looks like Advantec. OSB and Advantec as long as there 3/4" thick will work fine and has been used in millions of homes all over the world so I'm not sure where they came up with that idea.


Plywood is manufactured with the grain still intact, in layers whose grain alternates orientation 90 degrees. This is what gives plywood it's strength. OSB, MDF, HDF, etc.. all lack this particular feature. OSB, when used as a subfloor, actually tends to develop sags between the joists. It also makes a poor base for fastening hard-surface flooring as well, as it chips easily.


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## jasin (Jan 22, 2012)

oh'mike said:


> Hangers are not needed as the floor joists are sitting on a sill plate


I did not notice they were on the sill. Sometimes seeing things like that in a picture are hard to see. Nevertheless, you are right. Thanks for pointing that out. :thumbsup:


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## jasin (Jan 22, 2012)

joecaption said:


> Look again at the top of the floor joist, looks all punky to me.


If it is he still does not need to replace the whole joist as its obviously not sagging, twisted, or warped. He can too, just sister a small piece to that section anyways.


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## jasin (Jan 22, 2012)

I suggested right when I said he needs to have a mold abatement specialist come out and clean up the mold. Whether you agree with me or not that was sound advice.


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## joecaption (Nov 30, 2011)

Sanding, wire brushing, scraping is never used (unless you have no idea what your doing) to remove mold. It would grind in the mold spores deeper into the wood and make some air born causing it to spread.
Dry ice may kill the spores on the suface but do nothing to treat the spores deep in the wood of keep it from coming back.
In 30 years I've never heard of or seen any companys within a 100 miles of me that even does this type of treatment. So you would be hard pressed to even find anyone to do it.


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## Hardway (Dec 28, 2011)

http://www.concrobium.com/atHome_howToUse.php


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## jasin (Jan 22, 2012)

joecaption said:


> Sanding, wire brushing, scraping is never used (unless you have no idea what your doing) to remove mold.


It should not be used to remove mold. Many still do use these methods though.


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## jasin (Jan 22, 2012)

joecaption said:


> Dry ice may kill the spores on the suface but do nothing to treat the spores deep in the wood of keep it from coming back.
> In 30 years I've never heard of or seen any companys within a 100 miles of me that even does this type of treatment. So you would be hard pressed to even find anyone to do it.


TO determine if there is mold deep in the wood he needs to have a mold assessment done. That cannot be done here online! Someone actually has to come out to his house.


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## jasin (Jan 22, 2012)

Hardway said:


> http://www.concrobium.com/atHome_howToUse.php


He still needs to have a mold assessment done. Someone needs to evaluate the extent of the mold problem. This could be more serious then it looks.


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## JetSwet (Jan 21, 2012)

I don't see Scotte coming back to get any advice as there are to many opinions and disagreements here.
Mike & Joe are very knowledge in all eras flooring and haven't steered any one wrong on here.

Joe is correct on have some one poke around and really inspect the wood 
None of us will tell that how bad it is just by a photo.

Sent from my iPhone 4 ios5


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## Hardway (Dec 28, 2011)

jasin said:


> He still needs to have a mold assessment done. Someone needs to evaluate the extent of the mold problem. This could be more serious then it looks.


I am sure he does, did not say to handle it him self. Just better then bleach!


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## AndyGump (Sep 26, 2010)

jasin said:


> Plywood is manufactured with the grain still intact, in layers whose grain alternates orientation 90 degrees. This is what gives plywood it's strength. OSB, MDF, HDF, etc.. all lack this particular feature. OSB, when used as a subfloor, actually tends to develop sags between the joists. It also makes a poor base for fastening hard-surface flooring as well, as it chips easily.


This can not really be said of OSB, true it does not have a grain direction per se, it is wood flakes that are oriented in mats optimized for a particular strength axis.
It is less expensive in general than the same size and thickness of ply and I prefer to use it in construction.

Andy.


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## Daniel Holzman (Mar 10, 2009)

Gentlemen. I spent six months doing forensic investigations on houses damaged by flooding due to hurricanes Katrina and Rita. This included over 180 structures with damage ranging from wet due to flooding to catastrophic total destruction of the building.

Every one of the buildings I looked at had mold of one form or another. A few comments. First off, the standard treatment was to use bleach to kill the mold. Boric acid kills insects, I have never heard of it being used to kill mold. It might work, I have NEVER seen it used, we always recommended bleach, and the professionals used bleach.

Second, in all the buildings I looked at, there was no evidence of structural damage due to one time immersion in water. The mold was typically a shallow surface coating, and I never personally observed structural damage due to short term mold growth. A long term leak is another matter, the wood can be attacked by insects and other types of organisms, but the damage was generally very obvious. Deep penetrations into the wood, insect tunnels, obvious structural issues such as sagging etc. None of which is visible in the photos posted by the OP. Should it be investigated, yes absolutely, and of course if the joists are found to be structurally compromised, they should be replaced. From the photo, it looks like they are going to be fine once the mold is cleaned off.

Last point is that mold requires three things to grow. Warm enough temperature, moisture, and a substrate. You take away any of those items, the mold leaves behind spores, and stops growing. Spores are present everywhere, all the time, so you don't typically get all jacked up about spores unless you are OCD, which is a different issue. You remove the visible mold, fix the leak, dry the structural elements, rebuild, and relax.

As for OSB not being suitable for substrate, well you better tell the world, cause most people are using it rather than plywood. The currently produced OSB (which stands for oriented strand board) is quite a bit better than the old chipboard, and can be rated for use as indoor or outdoor substrate. Personally I prefer plywood, but then I am just a grumpy old engineer set in my ways, but there is absolutely nothing wrong with properly specified OSB.


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## jasin (Jan 22, 2012)

AndyGump said:


> This can not really be said of OSB, true it does not have a grain direction per se, it is wood flakes that are oriented in mats optimized for a particular strength axis.
> It is less expensive in general than the same size and thickness of ply and I prefer to use it in construction.
> 
> Andy.


I've replaced enough osb in my time to know that it is far from superior to plywood for sub-flooring.

Jason


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## Missouri Bound (Apr 9, 2011)

Step 1. Get a mold expert to check it out.
Step 2. After he tells you it's too far gone, remove the damaged area.:laughing:
Step 3. Sister a joist to the last dry joist and hang new ones from there.


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## joecaption (Nov 30, 2011)

http://www.pestproducts.com/timbor.htm

Just one of the dozens of brand names of products with Boric acid.
I've worked for a pest control company and now use many differant ones to do my pretreats and and treatments on fungus and also for things like Powder Post Bettles, old house bores, boring bees, and dozens of other insects.
Not one uses bleach to treat black mold or fungus on wood, works fine for small areas like on a drywall wall that there's mold only on the surface.
Boron is used to kill insects but also does many other things, it works by dehydrating the insect when they try to clean it off there legs. But it's also used as a mildicide, to treat rotted wood, a fire retardent ect.
Call any pest control company and ask them what they use to kill fungus under a house.

To have that much fungus this was not a one time leak there dealing with it's been going on for a while.


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## scotte1975 (Feb 3, 2012)

I come back....


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## scotte1975 (Feb 3, 2012)

Daniel:
I did end up calling ServPro back out to have the floor joists dryed. They "tented" the subfloor and put a dehumidifier and three fans in the kitchen. They treated all the joists with something that smells like a hospital. They should be coming later this afternoon to remove their equipment once again. They have told me that there were only a few places that had mold. I know the joists look really bad from the picture but they were really wet. I plan on replacing the subfloor with 3/4" plywood because i only have to replace (2) sheets and the price difference would not be that much and they will be under the sink and dishwasher mainly so if i ever have a leak in the future maybe the plywood will hold up a little better than the OSB. After i get the subfloor down i plan on laying cement backer board becuase we are going to go back with tile instead of vinyl. I just wanted to make sure the joists were completely dry before putting down the subfloor.


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## jasin (Jan 22, 2012)

scotte1975 said:


> Daniel:
> I did end up calling ServPro back out to have the floor joists dryed. They "tented" the subfloor and put a dehumidifier and three fans in the kitchen. They treated all the joists with something that smells like a hospital. They should be coming later this afternoon to remove their equipment once again. They have told me that there were only a few places that had mold. I know the joists look really bad from the picture but they were really wet. I plan on replacing the subfloor with 3/4" plywood because i only have to replace (2) sheets and the price difference would not be that much and they will be under the sink and dishwasher mainly so if i ever have a leak in the future maybe the plywood will hold up a little better than the OSB. After i get the subfloor down i plan on laying cement backer board becuase we are going to go back with tile instead of vinyl. I just wanted to make sure the joists were completely dry before putting down the subfloor.


I am happy you got the mold problem solved. :thumbsup: And plywood is definitely the way to go. I would get exterior grade plywood and stainless steel fasteners though so you do not have the same problem in the future. Best of luck to you in fixing this


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## Missouri Bound (Apr 9, 2011)

I know it's after the fact, but there are dishwasher drip trays available. They divert the water to the front of the machine so any leak is visible before they create a problem. You may want to consider that after what you have been through. You mentioned tile...perhaps you can build a "curb" around the dishwasher to create the same effect. At any rate, best of luck.:rockon:


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## scotte1975 (Feb 3, 2012)

Missouri:

I will be building a curb this time.


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## scotte1975 (Feb 3, 2012)

*Slightly Unlevel Subfloor*

Well, i put down the two new sheets of plywood subfloor. It looks great, but the problem is where the old 3/4" OSB meets my new 3/4" (23/32) plywood there is a slight variation. the new subfloor sits between 1/32 - 1/16" lower than the old OSB subfloor. The final product for this floor is going to be ceramic tile so I want to ensure that the floor is completely "flat". I am not sure how much variation I can have but I will be placing 1/4" cement backer board down prior to the tile. I have read about leveling low spots with asphalt shingles. Should i just put the backer board down and disregard the small deviation or should i place asphalt shingles to level the subfloor before placing the cement backer board?


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## jasin (Jan 22, 2012)

Missouri Bound said:


> I know it's after the fact, but there are dishwasher drip trays available. They divert the water to the front of the machine so any leak is visible before they create a problem.


:yes: Those are always a good idea!.


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## jasin (Jan 22, 2012)

scotte1975 said:


> Well, i put down the two new sheets of plywood subfloor. It looks great, but the problem is where the old 3/4" OSB meets my new 3/4" (23/32) plywood there is a slight variation. the new subfloor sits between 1/32 - 1/16" lower than the old OSB subfloor.


Lots of things can cause that. One that I can think of off hand is the fact that with age, incorrect installation, and moisture exposure osb will sag, dip, dimple, etc. stuff like that. It does not hold up as well as regular plywood. They've supposedly fixed a lot of this with the newer osb, but I still advice against using it. My advice too, is inline with The National Tile Contractors Association recommendations of not using OSB for sub-floor.


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## DCheck44077 (Nov 14, 2012)

*Where to start??*



jasin said:


> The National Tile Contractors Association recommends that OSB NOT be used as subfloor.


Of course they would say that, as any person knows the best subfloor for tile is backerboard, which also happens to be made by a lot of companies that also make tile and/or help fund said association... Much like oil companies telling you to change oil every 3k miles even tho 5k is max performing and most oil can go well above even that.

2 you are mistaken by thinking you could tell him everything that is wrong by simply looking at his picture, this how drastic mistakes are made, you have not seen it on-site but presume your word to be golden. Did he have a straight-edge and level on each joist, and measure to a constant the distance from the top/bottom to said constant? Well the picture has expired but my guess would be no. 

3. Most houses now a days are being built with all or paritally constructed parts that consist of osb or particleboard, because these variations are much stronger than simple plywood and hold up better to moisture, always verify explicitly why something is worse or better than the other.

4. Bleach is more than enough to kill surface mold, in fact most "mold-killing" products out there use bleach but call it by the chemical formula-s in order to trick you into paying more for something costs merely a couple bucks, but, it is not the chemical so much as how it is applied, and used. spraying and leaving it at that will not perform nearly as well as soaking it, and also providing fans and a dehumidifier. The other chemicals listed will simply do it faster. 

And lastly since you saw good reason to argue with everyone as to why u use plywood over osb, all i ask is you keep on using that plywood so we can continue making a living off of contractors whom build with substandard materials. Me i am about having repeat customers because my work has not needed more attention, others maybe like yourself prefer to fix your own mistakes by repeating said mistake. This is why often the same builder whom uses plywood also has the plumbing done with abs, and to code minimum (ie 1/2" copper/pex where 3/4" is better suited but not needed by code)

...I seldom apply for forums because of these ridiculous assumptions made, but sometimes every now and again somebody just has to hammer it home with their plastic nails and rubber hammer!


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