Black mould

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Posted by: from St Catharines
10/27/2012 at 9:21:19 PM

My daughter bought a house which has been leaking in the downstairs bedroom for quite some time. The drywall above the sliding glass doors in the bedroom, is totally black and spongy. The roof, soffit and facia will soon be repaired by a professional.

How can I repair the mould inside above the sliding glass doors which is only about 1" x 5" wide (drywall covered in black and spongy). Can I simply add a new piece of drywall over top of the damaged wall?

There is also damage to the drywall beside the glass doors but no evidence of black mould showing.

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Date/Time10/27/2012 at 11:01:31 PM

You never cover up mold, it will still grow and spread, even if you can't see it. In the case of drywall, you need to remove all of it, everything that is black or spongy. Drywall is cheap so remove evrything that is suspect.

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Date/Time10/31/2012 at 10:54:56 AM

You should take out the affected area. There may be mould in behind the drywall and that should be treated with a bleach spray, and then let dry. There is no point in re gyproking the area untill the necessary repairs have been done.

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Date/Time10/31/2012 at 4:25:49 PM

I would romove drywall all around the opening. And definatly along the baseboards for at least a few feet on both sides. This is the only way to see if the issue has spread.

In addition, if the drywall above the door is wet and mouldy, then I would suggest you open up the cieling drywall that is adjacent to it, as it is probably mouldy as well.

Any area you find that even has light mould needs to be treated. You can pick up the chemical at any of the big box stores. I also treat the area's with undiluted bleach as well. Then let it all dry for a few days prior to re-insulating and installing the new drywall.

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Date/Time11/1/2012 at 7:10:44 AM

No, you cannot repair over the existing drywall or in a mater of time it will come back through continuing to grow and start feeding off of the replacement drywall.

You should never cover mold by painting over it, covering it up with another material suck as wallpaper, panel etc... it will only get worse in time as it will continue to grow and mold actually thrives off of high cellulose content like drywall, insulation, ceiling tiles well as other materials that make up of a home or building. But before any of that correct the source of the problem ( the leaky pipe as its the water and moisture bieng the cause.

If not totally sure and dont have proper knowledge of remediation of Mold, calling a professional is highly recommeded as it could save you possibly thousands of dollers in the future and possibly a great deal of dangerous health concern now and in your future.


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Date/Time11/1/2012 at 7:18:51 AM

As well the Indoor air quality can actually change/ worsen when the drywall is removed without due care. The spores release, disseminate, and spread through the home.

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Date/Time11/1/2012 at 8:36:34 AM

You need to remove all drywall where mould is as well you need to inspect the rest of the wall. with that much mould it is likely that there is more in the wall that cant be seen.

That much mold indicates to me that there is a bigger problem. your insulation should also be inspected. it is likely that the interior of the wall will be wet. once the damaged area has been inspected and all mold removed ( you should take care to take special precautions like special masks, mold abatement may need to be done by a professional company if there is a significant amount. ), location has dried out and there is no more signs of leaking then you could go ahead and repair the space.

A solution of bleach and water or a mould killing spray should be sprayed where ever there is mold to kill any additional spores to keep it from coming back.

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Date/Time11/1/2012 at 2:26:02 PM


I would suggest that you open the drywall to remove any mold/mould that is in the drywall. I would open an area much larger that the 1" x 5" area that is mentioned in your message to be sure that all of the mold is removed. I am not sure what is the construction style of your home but if there is insulation behind the drywall then I would remove both the insulation, vapour barrier (if it has been installed) and drywall and replace them in the damaged area. I strongly suggest without any doubt that you need to remove any and all of the black mold. You may need to clean the area/material as a safety precaution to ensure that the mold is removed completely.

Once that is completed then you can install new insulation compete with vapour barrier and new drywall. Then the drywall will need to be taped and mudded complete with sanding.

Please do not just add a piece of drywall over the top as then the black mold will not be removed.

Lou Frustaglio

416-989-5890 cell

416-RENVOATE off

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