How to Remove Moisture From the Walls / Drying Wet Walls

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Posted by: from Toronto
2/20/2013 at 12:31:49 AM

Bathroom walls are soaking moisture, need advice to prevent and cure the issue ?


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Zeeshan from Pak Constructions in Cornwall
Date/Time2/20/2013 at 1:26:37 AM

Sometimes it happen when you don't use enough heat as it should be in winter!

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James C from Got Mold? ™ in Saskatoon
Date/Time2/20/2013 at 2:00:08 AM


Where is the moisture coming from? The source of the moisture must be stopped. If the drywall has been wet for more than 48 hours then it must be removed. During the removal process you should at minimum wear an N95 dust mask, protective rubber gloves, and if you run into more than 8-10 square feet of Mold growth stop work and contact a professional.

If the drywall hasn't been wet for more than 48 hours and is a clean water source (not out of toilet) the goal is to dry it with dehumidification and air movement within 48 hours.

Hope this helps, feel free to ask more questions.

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Date/Time2/20/2013 at 7:27:28 AM


Has this been going on for weeks? Or has it just begun. Are the walls damp evenly? By that I mean are all the walls wet or damp? This is important to know. Or is it soaking from top down or bottom up. Are your floors showing any evidence of moisture?

If the walls are damp everywhere and it has been for a prolonged period of time then the post you got at 2:00A.M. is the route to go. You will have to remove the drywall and check for any potential mold growth. If nothing else, look for the source of the water.

Having said that. You have to keep the heat at at least 20 celsius. Keep the furnace fan in the on position for at least two hours a day and run a dehumidifier.

Good luck.

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Robert from Electrilight Ltd. in Oakville
Date/Time2/20/2013 at 7:51:22 AM

This time of year it is normal to have moisture buildup on windows and if your humidifier is running in the home, it will make this much worse causing water to form along the sill and run down the wall. Is this a possibilty? If it is only that, turn your humidifer down and soak up the water daily to prevent further damage.

Triple pane windows do not cause this, mostly older or even double pane glass that is very cold from the outdoor temps.

If it is moisture from bath or shower, get a good fan installed and run it 30-60 minutes during shower time.

Is it drywall or tiles?

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Darrin from BioSweep Ontario in Kitchener
Date/Time2/20/2013 at 8:18:22 AM

Sounds like your bathroom lacks ventilation. Adding that would be a great start.

Ceiling exhaust fan, opening the window if there is one.

As far as any damage done to the walls that is hard to determine without seeing them.

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Date/Time2/20/2013 at 8:30:25 AM

Hi There,

Before anybody can help, uou have to explain exact problem you are having, otherwise is guessing game.

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Date/Time2/20/2013 at 8:37:14 AM

You need to install a bathroom exhaust fan.

Here are a few benefits of using bathroom exhaust fan; Removal of moisture, Removal of stinking air, Improved freshness, healthiness and hygiene see the link below for more details.

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Date/Time2/20/2013 at 10:17:29 AM

Assuming this happens during/after shower. It sounds like a better exhaust fan is required. ENSURE is it being exhausted to the outside not just into the attic space. Install a timer for the fan. Let it run for half hour or more after each shower.

If the problem persists, look into the insulation in the walls (and ceiling if applicable). If there is not enough insulation the walls will be cold and there will be more condensation build up.

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Date/Time2/20/2013 at 10:39:07 AM

Hi There,

Proper ventilation would prevent such moisture to accumulate on walls. Also using the cement boards will help as a water resistant material in bathrooms.


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Date/Time2/20/2013 at 12:38:05 PM

If you find your problem is continual high humidity from a variety of sources causing ongoing excessive bathroom humidity try to find a Contractor who can install a "humidistat". We install them for rental companies here in Ottawa. They allow you to preset the humidity level and automatically controls the fan switch. It turns on when the level exceeds your preset "normal" setting and shuts off on its own once the humidity level is normalized again.

Good luck.

Norm in Ottawa

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Govind in Toronto
Date/Time2/20/2013 at 10:15:17 PM

Really appreciate all of yours suggestions.

Well after reading all the suggestions I realized the shower exhaust fan is not working. That's the culprit, hopefully fixing that will solve the problem.

Thanks all !!!

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Jeremy from JD Reno in Whitby
Date/Time2/22/2013 at 12:39:12 PM

Chances are you don't have a fan or if you do your not turning it on enough or its not the right size for your washroom... Or it could also be an insulation problem.

I have opened up many of older 15-20 year old walls and found next to no insulation and an improper vapor barrier in washrooms, and in the winter this causes major moisture build up and eventually leads to nasty mold and rot.

Find out what is causing your moister and fix it, chances are your going to have to tear down some walls, if not renovate the entire bathroom... if it is an insulation issue with mold talk to your insurance provider they may be able to help if its a major issue and major renovation needed, but it all depends on where the mold is coming from and how its presented to the company.

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Govind in Toronto
Date/Time5/30/2014 at 8:29:33 PM

Thanks !!!

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