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Mold on roof sheathing


laufen
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I am selling my house. The inspection found mold under 50% of the roof sheathing, most likely due to excessive humidity in the attic. I had a roof installed 3 years ago (black composition instead of cedar shake). I don't know if the change in roof material affected the heat in the attic. The buyer wants $1600 off the selling price to deal with this. I don't live in my house, it was rented for 3 years. My realtor is trying to find out how bad the mold is, etc. What do you think it could be and what are ways to fix this for the sale? Should I just accept the $1600? Any help would be appreciated.

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Did you have shakes originally? Around here wood roofs did not have ventilation since most were self venting. Then they either put asphalt shingles over the wood shakes or tear them off and put decking and asphalt shingles on. They almost always forget to add vents when they do this.

1600 doesn't sound like a lot, but I guess it depends on how bad you want to sell you home and how much your asking for it.

Donald

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Yes, there was shake originally and all was torn off before the composition roof was added. Would venting be something the roofer would be expected to do? Does homeowners insurance cover this? Does anyone know how to get rid of the mold or should a professional be called in?

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It might not be "mold" at all. When people think of "mold" they are usually thinking of stachy or one of the alleged "toxic" varieties, when that might not even be the case.

In most cases that I see, this is caused by exhaust fans that are allowed to vent into the attic. Lots of roofers don't like to install small outlets, known as rain caps, through the surface of their shake roofs, because of the difficulty flashing them so they won't leak. So, unless you specified they be installed when the shake roof was replaced, this might not have been done during the reroof and your fans continued to vent into the attic. That excess moisture is what might have caused your discolored sheathing. Shake roofs breath really well. Because of this characteristic, I find them performing fine all the time when under-ventilated - even with exhaust fans venting into the attic.

I also find discolored decking all the time, where the shakes have been torn off, solid decking has been added and the roofers didn't increase the amount of ventilation or install rain caps for the exhaust fans. Most of the time, the discoloration ranges from light to dark gray, depending on the length of time that the attic has been under-ventilated. In the majority of these, the deck is still solid with no sign of delamination or bloom. In these cases, I recommend that they correct the ventilation and treat the underside of the roof with BoraCare - a glycerin-borate mixture. BoraCare is toxic to all forms of fungal growth and soaks into wood up to 1-1/2 inches. In an attic, it effectively arrests any fungal growth in the wood and prevents it from spreading. This usually does the trick.

Even if it isn't "toxic mold" in the classic sense, once the ventilation issues are corrected, the discoloration needs to be arrested and treated so that it doesn't develop into something else and spread to your framing and the house. Around here, the outfit that specializes in treating attics and crawls with BoraCare gets a little over a dollar a square foot and insists on doing all exposed wood in the space infested, or they won't do the job at all. Given the stigma that attaches to the word "mold" these days, Chad is right, $1600 is cheap.

ONE TEAM - ONE FIGHT!!!

Mike

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Is the roof sheathing plywood? Are there roof and/or soffit vents? Without pictures or specific descriptions, it's not possible to offer efficient advice. The larger concern is not mold, but the water that allows the mold to propogate; where is it coming from?

There is the distinct possibility that it is only a minor little bit of black mold that isn't going to effect much of anything; it exists in about half the attics I look at. OTOH, depending on purchase price of the house, $1600 might just be the easiest & fastest way to deal w/it.

Most inspectors, and definitely myself, point out various mold "now" that I would have never even mentioned "then". This is self preservation more than any real concern related to mold. I suspect that your situation might fall under that umbrella.

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Hire your own inspector to take a quick look for you. If they say you have mold on 50% of the attic surface, take off the $1,600 and have the new owner sign all types of releases for the mold and any subsequent problems(get an attorney to do it). $1,600 is cheap when it comes to abatement of mold.

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Kurt is right,

Without specifics, it's difficult to say. If the roof is under-ventilated and exhaust devices are venting into the attic, the inspector should have pointed these out in his report.

However, even if the roofer screwed up, if you contact him, attempt to get him to rectify it and he refuses, it'll probably cost a whole lot more than $1600 to take it to court and get a judgment. If you report it to your insurance company, you'll probably generate a CLUE report that will follow you later on and could end up costing you a whole lot more than $1600 over the ensuing years.

If it were me, I'd eat the $1600 and call it the cost of an education. However, it's your call, nobody can make it for you.

ONE TEAM - ONE FIGHT!!!

Mike

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The purchase price of the house keeps being mentioned so it is $175,000 (25 year old house), so $1600 isn't alot, but I like to check things out before I agree to anything. Your comments have been very helpful. I thnk the mold isn't too serious since the inspection report doesn't sound alarming. It states "Mold was found on the under side of at least half the roof sheathing. This may be due to excessive humidity in the attic. It is recommended to have a cleaning and restoration company specializing in mold treatment evaluate the attic and make recommendations regarding treatment of the mold and identification of the source of mold. Also, consider improving ventilation in the attic and reducing humidity in general in the house."

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Originally posted by laufen

The purchase price of the house keeps being mentioned so it is $175,000 (25 year old house), so $1600 isn't alot, but I like to check things out before I agree to anything. Your comments have been very helpful. I thnk the mold isn't too serious since the inspection report doesn't sound alarming. It states "Mold was found on the under side of at least half the roof sheathing. This may be due to excessive humidity in the attic. It is recommended to have a cleaning and restoration company specializing in mold treatment evaluate the attic and make recommendations regarding treatment of the mold and identification of the source of mold. Also, consider improving ventilation in the attic and reducing humidity in general in the house."

$1600 may well be the bargain of the century since the remediation for fungus (of which mold is a sub species) typically requires removal of the affected cellulose material. Wood can't be cleaned.

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Originally posted by laufen

I just have one more question. The roofer that did the job gives a 10-year warranty. Is there any chance the mold on the sheathing happened because of his work 3 years ago? Is it worth calling him?

The mold is most likely caused by excessive moisture in the attic, as others have mentioned, due to inadequate ventilation and/or the discharge of vent fans into the attic. If the vent fans are properly discharged to the exterior of the dwelling (and have been all along) them IMO the monkey is on your roofer's back for performing substandard work by not upgrading the ventilation when he replaced the wood shingles with comp shingles. A call can't hurt asnd good luck.

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