Shower leaked into rasied floor in basement - Microbioligits wants to use formaldehyde gas

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Posted by: from Lasalle
9/3/2013 at 8:39:14 PM


I have a hard wood floor raised about 4-6 inches off the cement basement. The slab seems to dip from around 2 inches at the extremities to 6 at the center. The shower leaked for the past 5-6 months without us noticing until recently. When we opened the trap at the center of the basement there was over 2 inches of soapy clear water. After taking the washroom floor out, we noticed 100% proof that the leak came from the shower in the corner of the basement - the rest of the basement is living space with beautiful expensive hardwood flooring. Some of the wood that was used to raise the ply wood, seems black at the base where the water pooled. Imagine a dish with a dip in the middle, when you poor water it sits there and continues to rise. Luckily we caught it before it reached any of the hardwood, but still ... we had at least 4 inches at one point from the looks of it. The humidity is hovering from 80-89% at all times now. We did take out all the tiling and plywood floor out of the bathroom but left the remainder of the floors in tact outside the washroom.

We had a microbiologist take some samples and he told us there is a small amount of mold, nothing to be worried about, and that the mold is only in the subfloor not air bound. He wants to use formaldehyde gas to kill any mold spoors then dry out the floors before we begin rebuilding the bathroom floor and not touching any of the hardwood throughout the remainder of the basement.

So questions are...

1 - is using formaldehyde gas a good option to kill any mold spores. He swears it's the full proof method and aside from exiting the house for a day, it's safe.

2 - Do we really need to take out the remainder of the flooring even if the water never reached it?

3 - Should we be worried about the wooden supports that did get soaked in water for several months - we can't see them without taking out all the flooring.

4 - Who can help?

5 - Approximate cost for a 24X24 basement with a corner washroom with full bath?

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Date/Time9/3/2013 at 10:25:32 PM

Question one... nuts.

Two... no.

Three... yes you should worry about that.

Four... any good tradesman but not your biologist.

Five... 25000$ and up.

User Icon
Date/Time9/3/2013 at 11:47:49 PM

I am not sure where you are located but based upon all you have said, if you were here in BC then we would recommend NOT to use formaldehyde or any other dangerous chemicals. The issues could be solved reasonably easily using our Perma Shield bio-fluid. This would be introduced to the underfloor areas using our non thermal tri-jet fogging system and followed by a pressurized spray.

This product is totally all natural and contained no toxins, no poisons and no chemicals and what it does is to penetrate all timbers and remove all bound moisture completely, evaporating it as a form of ethanol gas. The fibers of the wood are treated and sealed and the product will completely alleviate mold, spores, germination and even insects that may be in there. The product works best of wood that is wet or damp and in areas of high humidity. It also prevents the timber from warping, cupping and splitting and will remain there as a permanent one time treatment.

My company actually manufactures this product ( among others ) down in Minnesota USA and it has been used successfully for many years now in all types of timber treatment and mold remediation contracts.

I hope this may be of some assistance to you.

Hopefully you will find a better solution than suggested by your microbiologist.


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Renato in Lasalle
Date/Time9/4/2013 at 8:54:07 AM

@Robert from Hartman's Construction & Property Services:

We live in Quebec.

@Nicolaas from Classic Home Maintenance:

You answered NO to us having to replace all the flooring, but then answered YES to having to worry about the floor joists that hold up the floor. However, I don't see how we can replace or fix the floor joists without first destroying the hardwood floors. Any suggestions?

Thanks for your answers.

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Date/Time9/4/2013 at 3:25:51 PM

Good day,

Please note that due to your explanation regarding the black mold that was located in the space it would be a good idea to take it seriously. Mold is definitely not something to mess with. Contact a remediation company and get a second opinion, if needed.

Thank you and our best wishes to you!


Cindy McCullough

Divine Hardwood Flooring

Edmonton, AB

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Date/Time9/6/2013 at 4:21:45 PM


I found the whole thing of using formaldehyde gas so rediculous that I wasn't taking this serious anymore.

All I can suggest now is to talk to a mold remediation company and get the issues resolved. This requires a on site inspection and perhaps testing.

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Date/Time9/6/2013 at 5:07:00 PM

Ok my first question would be... why did the shower leak.. who done that work.. was it a poor workmanship project from the beginning. If so... I would then start to question what else is wrong.

Sure spray the underside to kill it all..but what other sort of issues are you going to have down the road?

I have seen this way to many times here in Calgary.. a lot of people come into a house looks nice and all... but what is in the walls... hidden junction boxes and plumbing not to code, holes to allow bugs and what not into your house and they are left with a huge mess and huge bills to fix properly.

I would be looking at the entire project in a whole. Your hardwood is not worth anything if everything else around it is going to fall apart. Would you put bald tired on a bmw?? Also what about your insurance, isn't that why you pay for it??? A lot of factors to think of, not just trying to save this hardwood. Cheaping out and not doing a proper job will cost you way much more down the road to repair.

Robert had a good suggestion, and so do the others about mold remediation, but don't cheap out and just cover the problem, fix it to last... just my opinion.

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Date/Time9/16/2013 at 2:11:20 PM


Sorry to read about your leakage problems.

After reading your post, here are my suggestions,

First, any area that was in constant contact with the water, such as in the bathroom and near the drain should most definatly be treated for the mold issue. Yes I would pull up the whole floor in the bathroom and then examine the area running towards the drain. If the would subloor there shows signs of black mold, then I would continue to remove the flooring and deal with it. If there is no eveidence of black mold there you are getting lucky.

Then check the area around the drain in the family room, you have said there is black mold on the subfloor there. If so, there are a couple of things you can try. Rent an industrial vacume ( a unit that can be fitted with an exhaust hose as well. Duct tape the intake hose to the whole in the flooring by the drain and pull the exhaust vent out through a window. Tape up the hose at the window side as well.

Then run the unit for about six to eight hours.

I would then remove the hose, plug the drain opening and very slowely pour about three gallons of bleach by the shower, where it leaked. By slowely I mean a couple of cups evry ten or fifteen minutes.

Leave that overnight, and then run the vacume again. Check it the next day. I think you will find no evidence of the mold where it can be contacted.

This is the route I would go if I was looking to save money.

By the way, I would also have a plumber run a snake to clean out the drain in your basement floor. If you had pooling by it, it is either not draining properly.

Now having said that if it was my house...I would remove all of the flooring, and subflooring. And start with new. I would install a sub floor with a built in plastic drainage system such as Dry Core. It is easy to install. I would then lay down the foam underlay and install laminate flooring. There are fantastic choices out there today. So picking up something that you would love more than your existing hardwood should be easy.

Be sure the shower is repaired, and your drain works properly.

Then you will never have to worry about it again.

Thats my two cents.

Good luck,

James Fram

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