Mold in Attic

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Posted by: from Burlington
4/8/2014 at 9:46:23 AM

We are in the midst of buying a house. The home inspection was great until he went into the attic. This house has a Mansard roof and the entire sheathing is covered with mold.

We have been looking into the cost to replace the roof, sheathing, rafters, insulation, mold treatment and eaves trough.

Is this enough to take care of this mold problem? Should I be worried that the mold has spread to the bedroom walls/ceiling also?

Here is a picture of the sheathing.

Mold in Attic
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Date/Time4/8/2014 at 1:34:45 PM

The presence of mould in an attic is commonly caused by poor ventilation from vapours within the home escaping into the attic and not being effectively exhausted. There are many parts that make up the system of a house that lead to a condition like this. Replacing the roof, insulation, trusses, etc will make your attic look brand new again....for awhile. Assessing the cause and dealing with the mould is what you should do so the mould does not come back with or without a new roof.

As for mould spreading to the drywall, that depends if there were roof leaks or other water-related issues capable of causing mouldy drywall.

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Tricia in Burlington
Date/Time4/8/2014 at 3:15:30 PM

The roofer that I spoke to yesterday said that he would bet money that there is a bathroom vent that is venting into the attic space.

The home inspector mentioned that from what he could see (the attic is a small space because of the pitch in the roof) it might be caused from not enough ventilation and/or blocked ventilation.

The plan in place so far would be to replace the shingles, sheathing (rafters ? if needed), insulation & eaves trough. We would also make sure there is enough and proper ventilation. Once everything is removed we would have mold remediation. We also are planning to use the closed cell spray insulation for the attic. Our plan is to fix the issues that are causing the mold ? or else all this effort and cost would be a waste.

I am curious if it is possible that the drywall on the 2nd floor (walls and ceiling) could be affected also. I am assuming the only way to find out for sure is to remove the sides of the Mansard roof? We do not see any visible damage from the inside of the house (walls). I just worry about what we could be getting ourselves into.

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Date/Time4/9/2014 at 10:55:04 PM

Without actually viewing the site I can only offer suggestions...

I don't believe you will need to replace trusses or rafters. The sheathing and roofing materials are a good idea. Likely less costly than attempting to clean and remove in such a confined space.

The source is quite possibly the of restricted intake and/or exhaust. If a bathroom and or laundry vent is open to the attic... that is most definitely a contributing factor.

Checking the vapour barrier for signs of moisture will be a good indicator of possible mold issues below the ceiling line. The only sure way is professional inspection.

Process I would take is... Remove sheathing, all insulation material, ensure positive seal to all vents to the out side of the structure, fully clean and seal all attic surfaces. Ensure proper, balanced, intake and exhaust for the attic. Re sheet the trusses, ice and water shield and shingle.

If this is a purchase... I would take a pass. Unless the price is right.

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Date/Time4/10/2014 at 10:24:27 AM

The best thing you can do before all question is doing visual inspection on the molding area discover where the problem came from and fix. Some situation like that is very simple to fix and some not all, depending of visual inspection to discovery the problem point.

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Date/Time4/11/2014 at 7:27:31 AM

Firstly check to see that all penetrations into the attic space from heated space below are sealed. Such sealing (using caulk or low expansion foam) should be done around plumbing vents running up through attic floor, ceiling light fixtures, pot lights should have insulated approved covers without which warm moist air can enter into attic. Also ensure the attic hatch is insulated and weather stripped. As to mould, please do not assume its mould. To confirm mould it must be tested.

Further mould and remediation by unscrupulous contractors and due to media overhype may not even be a health hazard, and any existing staining or mould will not thrive if the conditions creating the favourable conditions are not addressed.

The wood framing may be fine and may not need replacing at all if the conditions allowing moisture to accumulate are not addressed, and once moisture is removed the mould can no longer grow.

Please read the following on mould and mould testing and the hype and the bunk before you do anything else.

Read the topics on the right hand column -

- Indoor Mould (Mold) Issues

- Are mould screening samples valid?

- Truth about mould health effects

- Mould Remediation Myths

- Myths of mould sampling

- Mould sampling confounders

- What is "toxic mould?"

- Myth of toxic mould in marijuana

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Date/Time4/17/2014 at 8:47:03 PM


Why don't you get the space air tested to see if the mold is actually a problem. People get freaked out by mold, but sometimes it's not as bad as one would think. You should be able to find someone online to test the air quality.

Here's the next question, is the plywood and trusses rotting out? If so, then you would definitely need to replace the whole roof structure. If all is good, get someone to install proper venting (in alberta it's 1/200th of total roof area).

Start at the easiest solution, and work your way up.

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