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What to do with previously mouldy walls.

What to do with previously mouldy walls.

Old 03-22-15, 06:08 PM
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What to do with previously mouldy walls.

Hi guys. I'm new to this forum, and am new to diy but im enjoying what I've done so far but I have questions for my next project.

We have a double story house on a hill, in which the first floor is cut into the hill. So it's almost completely below ground apart from the front of the house.

In one room we found mould on the walls while we removed the previous owner's built in cupboards and skirting boards so we removed all the affected plaster (the rear wall where the cupboard was and the side exterior wall). Behind the plaster on both walls is brick, the plaster was just glued straight onto the brick. The Brick on the side wall is the exterior brickwork I believe.

I've got some mould killing compound that im going to wash all the walls down with, but am wondering what to do with the walls and flooring afterward. Can I leave the brickwork as is and have a brick wall? Should I coat it with something? Should I put up some plaster again? Is there something I should be doing in this area to protect the brickwork from more mould?

Also I was looking at putting laminate flooring down and wondered if I should put something down first to protect against mould again. The floor is currently just the concrete slab of the foundations. There are also a few cracks in it should I be worried?

I can take some pictures when I get home if it helps describe what I'm talking about.

I just need to know the best options I have for finishing the walls and flooring with the least chance of mould coming back again.

- Nick
Old 03-22-15, 06:59 PM
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Pictures always help.

The mold indicates the wall was either cold (below the dewpoint) which caused it to get condensation on it when the conditions were right for it... or wet from groundwater seeping in through the mortar. It could indicate that waterproofing needs to be done on the exterior wall. We can't tell which.

If the mold was only behind cabinets that have since been removed, it was probably just a cold area and a dewpoint issue because the cabinet blocked the rest of the air in the house from warming that spot. Same thing might happen behind a big picture that's hanging on a cold, underinsulated wall.

Since you haven't completed your profile, we have no idea where you live or how cold it gets there. But it sounds to me like you need insulation and framing added if you intend to hang any gypsum wallboard there again. Sure, you could leave the brick exposed but it will probably sweat when the conditions are right for it. Unless you live in Yellowstone, the ground is always colder than room temperature.
Old 03-23-15, 12:09 AM
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Thanks for the reply. I've updated my profile now. I live in Australia, just outside Melbourne. The climate fluctuates wildly here, from 5 degrees to 42 degrees celsius (40F to 108F). I've just got home and taken some pictures and also drawn out a few diagrams to show the structure of the room and the walls I'm working on.

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I've only removed the problem walls so far.

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Photo from other end.

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Photo from Outside the house showing external staircase that's ruined. I'm guessing the dirt right up against the wall is causing the mould problems in this area.

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Plan view

I'm guessing I should remove all the plaster off all the walls? The walls I've left have no evidence of water damage or mould but should I remove them anyway?
Old 03-23-15, 03:06 AM
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Mold needs 3 things to grow; moisture, heat and a food source. Remove any one of the 3 and the mold won't grow. I suspect moisture was migrating thru the wall and the cabinet was restricting air flow preventing the moisture from escaping. Leaving the wall exposed should help.

Laminates don't fare well when there is moisture. An easy way to check the slab for moisture is to tape some plastic [garbage bag is fine] to the slab and then check under it several days later for moisture.
Old 03-23-15, 03:42 AM
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You are using the term "brick" Is it brick or concrete block? Marksr has the solution for keeping it from growing, but you have to get it all, or it will spore out and grow somewhere else. I have done reconstruction after professional mold remediation and when I find the hint of mold, I stop work and call them back to take care of it. I won't expose my guys to it.

Pictures would certainly help. Laminate won't. It would be the last thing I would install on a basement floor.
Old 03-23-15, 10:26 AM
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I merged the two threads and deleted the redundant postings.
Old 03-23-15, 01:16 PM
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Thanks mod! Once I realised it was posted twice I looked for a delete thread option but couldn't find one.

Anyway i have setup the garbage bag thing marksr mentioned and will see the results in a few days.

If there is moisture laminate and vinyl flooring is out I suppose. Maybe that epoxy resin floor paint would be ok?

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