Author Topic: Can new roof substitute for mold remediation? Moldy pics attached!  (Read 6716 times)

Lifeblood

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I could use some help evaluating this situation. My MIL's home had a 25 year laminate roof installed in 1998. With little maintenance since then, we have a number of problems to contend with. I have listed them below, with the estimated price to outsource.

Mold remediation in attic: $3,800 (this is mainly to treat the mold seen in the pictures)
New Gutters + related carpentry to address problem areas: $1,500
Moss removal: $500
New venting: $535
Total: $6,335

And, in about 5-8 years, a new roof: $5,000? $10,000 (this is a guess)

After all of this, we need old insulation removed and new insulation installed: $2,500

With all of this in mind, I am starting to think the best course of action is to get the new roof installed now, and in doing so, have the moldy sheeting removed, new venting and gutters installed, various carpentry issues addressed, etc. Sure, the cost would be a bit more than a normal roof, but well-worth it, I think. Afterwards, we could have the new insulation put in and be good to go for a long time. I would consider doing a 50 year roof, or perhaps even a metal roof.

What other factors should I consider?



worms

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #1 on: February 15, 2015, 12:36:23 AM »
I'm not in a position to advise on your situation, but I am appalled at the concept of a "25 year roof"!  Apart from the odd slate replacement, my roof is essentially as it was when installed in 1870!

Greg

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #2 on: February 15, 2015, 12:06:15 PM »
I'm not familiar with laminate roofing, perhaps you are referring to asphalt composite shingle roofing.  In any case, the roofing looks like is was not done properly. 

The sheathing does appear to have water damage, and so a complete tear-off down to the trusses would be my recommendation, but I'm a design-build professional not a roofing contractor.

Metal roofs are superior, especially for low-slope applications.  It's hard to estimate the cost without knowing the square footage, roofing is often estimated in "squares" which are 100 sq.ft. units. 

Consistent soffit and ridge venting would be a bonus as would deeper insulation and air sealing, all of which could be done when the roof is open. 

paddedhat

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #3 on: February 15, 2015, 08:57:19 PM »
It appears that there are two serious issues shown in the pictures. First, there is virtually no insulation in the ceiling at all. Assuming that the bottom chord (ceiling joist) of the truss is a 2x4, then there are places where the (blown fiberglass?) insulation is no more than an inch thick. Second there appears to be absolutely zero soffit venting. Given that, it's probably safe to assume that the roof lacks a proper, continuous ridge vent also.

The first goal here should be to retrofit the attic with everything a modern roof structure needs to perform effectively. First issue is ventilation. It needs to have continuous soffit and ridge venting added. The sorry- assed gable end vents need to be blocked off, they are doing little at the moment, and WILL screw up the performance of the continuous venting system. Next step is proper baffle trays to prevent blocking the air flow under the rafters. After the trays are stapled up, you take short pieces of fiberglass batt insulation and roll them up, like a small sleeping bag, and jamb them into the area where the ceiling meets the baffle tray. This seals the area, and prevents blown insulation from ending up out in the vented soffit. Finally, a new layer of blown in insulation. Cellulose is great for this application, and a level of R-50 can't hurt.

As for the mold, I would first determine if the roof sheathing suffers from minor mold issues, (as it appears to) or if it is truly saturated and unusable. The way to properly inspect the sheathing is with a sharp tool like an awl or ice pick. If it is truly rotted to the point of structural failure, you will be able to easily push and awl right through it. It will also typically have visible deflection between the trusses, and feel soft when you push up on it. If it's really shot, you will be able to easily dig through the laminations with a screwdriver, or pry bar. If it's just mold, I would hit it with a mold killing agent, in a pump sprayer, while wearing the proper protective clothing and respirator. I would use bleach, and have done so, numerous times, with great results. That said, any time you mention bleach on a forum, somebody shows up to claim it is of no value. BTW, this is a classic case of the mold remediation being a scam. Four grand for a light coating on sheathing, sorry but no. It is not in the interior of the home, it can be easily addressed as a DIY project, and the issue will resolve itself when the roof is properly renovated. I remember my insulation contractor doing battle with a mold remediation contractor that was trying to scam a homeowner. The guy tested the air in a well ventilated attic and it said was positive for mold. My insulator told him to stand in the yard and do the same test. The mold contractor tried to change the subject since he knew he had been caught. There is mold everywhere and you will find it in the air in your yard, in your house, or in a well ventilated attic.

Once the roof is functioning properly the mold issues will resolve, as the sheathing will dry out, and no longer support mold growth. Remember, especially in your location, mold is everywhere, and it will grow in the right conditions. If you remove the dampness from the sheathing with proper ventilation, you remove the right conditions for mold growth, permanently.
« Last Edit: February 15, 2015, 09:15:21 PM by paddedhat »

paddedhat

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #4 on: February 15, 2015, 09:25:54 PM »
I'm not in a position to advise on your situation, but I am appalled at the concept of a "25 year roof"!  Apart from the odd slate replacement, my roof is essentially as it was when installed in 1870!

Your roof could easily cost 10-15X as much as a modern asphalt shingle roof. Given that most folks live in a house for less than a decade before they move on, I'm pretty sure that the reason that slate roofs fell by the wayside is that it's a bit tough to justify an extra  $30, 40, 50K or more, for shingles that will still be looking good in 2115. Slate is wonderful, but I wouldn't want to make a living selling it. I was raised in a house that turns 100 years old this year. It is a solid brick house, three layers thick, with a black state roof. The majority of the exterior has had virtually zero maintenance in the last century, and it might last another century with a bit of care to the slate and brick.

Mega

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #5 on: February 17, 2015, 09:24:17 AM »
I have learned a lot about this in the past few months.

Long story short, all "conventional" roofs will eventually grow mold in a climate subject to snow. Why? Even with perfect ventilation, you will still get condensation during snow melt.

Only way to permanently prevent mold in the attic is to use closed cell spray foam insulation on the underside of the roof deck, thereby bringing the Attic within the building envelope.

What is the slope of the roof? Low slope roofs are PRONE to mold due to the low volume of attic vs ceiling surface area (leaks remain same, but are a much bigger problem as there is less volume to spread across, less vertical space to encourage movement, ect.)

paddedhat

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #6 on: February 18, 2015, 06:38:33 AM »
I have learned a lot about this in the past few months.

Long story short, all "conventional" roofs will eventually grow mold in a climate subject to snow. Why? Even with perfect ventilation, you will still get condensation during snow melt.

Only way to permanently prevent mold in the attic is to use closed cell spray foam insulation on the underside of the roof deck, thereby bringing the Attic within the building envelope.

What is the slope of the roof? Low slope roofs are PRONE to mold due to the low volume of attic vs ceiling surface area (leaks remain same, but are a much bigger problem as there is less volume to spread across, less vertical space to encourage movement, ect.)

Hate to be so harsh, but this is absolute bullshit. There are countless millions of homes with traditional, yet properly designed and installed, insulation materials and ventilation techniques, that are mold free. The biggest error of your "logic" is your claim that condensation and long term saturation are inevitable. Roof sheathing may, or may not, develop temporary condensation during snowy, winter conditions. That said, I have been in dozens of the homes I built, in a relatively harsh mountain environment, and have never observed condensation, or signs of moisture on the back side of any sheathing. The fact remains however, assuming a theoretical condensation event, that the sheathing can, and will quickly dry out to a level that will not support mold growth, if the ventilation is effective.

Now, on to science, and vigorous proponents of ideas. First, I want to be perfectly clear that using adequate amounts of closed cell foam on the "lid" is one hell of an effective way to insulate and seal a home. It may in fact, be the very best way to do it. It is also extremely expensive, and very hard to justify, given the average ownership duration of a home in our society.  Secondly, be very careful when reading the claims of anybody who pushes any building technique with claims like, "all conventional attics get moldy" or "this is the only way to do it right".  There are too many of these proponents that either have a lot of skin in the game, or are such zealots that they conveniently gloss over the down side of whatever they are pushing.

 IMHO,  a great example of this is are the proponents of the insulated concrete form systems that use hollow foam blocks to build structural walls. I have dealt with ICF folks who are convinced that there are absolutely no issues with the system, and only uneducated Neanderthals build outdated stick houses.  OTOH, I know builders who gave it an honest shot, built a few homes, found many problems, and eventually abandoning the concept as too troublesome. Just one example of the gap between a persuasive article on line, or even a whole movement pushing their agenda, and how things go in the real world.

Bottom line, a well insulated and ventilated traditional roof will perform extremely well, for the life of the structure. Closed cell spray foam is an awesome way to insulate, at a much higher cost, than tradition techniques, and may, or may not be good value, depending on extremely variable, individual situations.

James

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #7 on: February 18, 2015, 07:01:18 AM »
I don't see anything in the pictures that indicate the sheathing needs to come off. I assume you aren't doing the labor yourself (there is a big difference, so that is key), sounds like you are dealing with businesses trying to sell you something. That is a hard place to be, because you can't always trust what they say. They may mean well, but it is your money they are spending.

I would get multiple estimates, and see what they each say about the repairs needed. To me it looks like you need to spray with bleach, remove insulation, and add the right baffles, venting and insulation. (as paddedhat recommended also) The shingles are an entirely separate issue, whether you need shingles and gutters depends on the condition of what is there. But the presence of black or white mold in and of itself in an attic is not an indication to replace things, especially when it is obvious the cause as it is in the pictures.

If you aren't doing the work yourself, it may very well be cheaper to have the roof torn off including some areas of sheathing that are worst (probably not all), replace the insulation and apply new sheathing as needed. That saves the labor of removing insulation from the attic from the inside, makes it easier to get in for the bleach spraying, venting, etc. But the key is getting everything done right and at the right cost, the sheathing is only in need of replacing if there is structural issues.

A lot depends on what the overall situation is as well, both financially and for your MIL in general. If she cannot adequately monitor and maintain the house, but has a long time to use it, then maybe having the metal roof and other major things done at this time makes sense. Having the roof "taken care of" for the rest of her life is a huge thing off everyone's mind. But if money is tight maybe the current shingles have more life and maybe cost plays a bigger role in what they are replaced with.

guitar_stitch

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #8 on: February 18, 2015, 11:18:49 AM »
I see more water staining in the photos than mold/fungus.  While the water is a problem that needs to be fixed, it is not an automatic condemnation of the building materials.  The entire mold epidemic is so far out of hand that it's laughable.  Most health issues from excessive mold spores present like seasonal allergies.

Steps I would take if it were my house:

1) Fix all water leaks and increase venting.  Make sure the soffit vents are not plugged by insulation.  There are spacers you can buy and staple to the trusses to ensure that the vents don't get blocked.  I wouldn't worry about sealing off the gables.
2) Lightly spray all surfaces with a bleach solution to deactivate any fungus.
3) Increase the insulation in that place.  You want 12-18" deep.  Looks like you barely have 5 1/2".

paddedhat

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #9 on: February 18, 2015, 06:02:24 PM »
Stitch, I basically agree but there are a few things that I would question. First, from the pics. it's not even clear that there are soffit vents, as far as I can see? Second, If you are attempting to ventilate properly, with continuous soffit and ridge venting, the gable end venting has got to go. Venting is a result of thermodynamics, or hot air being drawn up each rafter bay by convection currents, and by pressure differential, when wind passing over the peak creates a suction that "vacuums" air from the attic. If the gable vents are allowing a lot of intake, there will be a short circuit from them to the ridge vents. I first discovered this when investigating a very odd situation, where I had a customer call and ask me to take a look at ceiling leaks in the dead of winter. It was a place with a simple gable roof, lots of soffit and ridge venting, and gable vents at both ends. I got into the attic and was blown away by what I found. We had just had a long storm in very cold weather, so there was a considerable accumulation of very dry snow in the area. The entire attic was full of 5-6 feet of snow. The wind pressure had created such a vacuum on the needless gable vents, that it had filled the attic up to the bottom of the vents. There were thousands of cubic feet of snow, slowly melting and destroying the ceilings in the building. I later talked to roofers who claimed that they had similar situations at the same time, even if somebody left a gable end window slightly open in a walk-up attic.

guitar_stitch

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #10 on: February 19, 2015, 12:48:12 PM »
True...  If there is a soffit vent, it's a really really short soffit.

bacchi

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #11 on: February 19, 2015, 01:28:16 PM »
Second, If you are attempting to ventilate properly, with continuous soffit and ridge venting, the gable end venting has got to go. Venting is a result of thermodynamics, or hot air being drawn up each rafter bay by convection currents, and by pressure differential, when wind passing over the peak creates a suction that "vacuums" air from the attic. If the gable vents are allowing a lot of intake, there will be a short circuit from them to the ridge vents.

I disagree with the "short circuit" theory. While I agree that those gables you mentioned had some problems, they're not making the soffits and ridge vent useless. If the soffits exist and work and are balanced, then the gable vents will work as intended.

http://homeenergypros.lbl.gov/forum/topics/the-short-circuit-theory-keep-or-remove-those-gable-vents

http://www.greenbuildingadvisor.com/blogs/dept/building-science/lstiburek-s-rules-venting-roofs



paddedhat

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Re: Can new roof substitute for mold remediation? Moldy pics attached!
« Reply #12 on: February 19, 2015, 06:47:49 PM »
Second, If you are attempting to ventilate properly, with continuous soffit and ridge venting, the gable end venting has got to go. Venting is a result of thermodynamics, or hot air being drawn up each rafter bay by convection currents, and by pressure differential, when wind passing over the peak creates a suction that "vacuums" air from the attic. If the gable vents are allowing a lot of intake, there will be a short circuit from them to the ridge vents.

I disagree with the "short circuit" theory. While I agree that those gables you mentioned had some problems, they're not making the soffits and ridge vent useless. If the soffits exist and work and are balanced, then the gable vents will work as intended.

http://homeenergypros.lbl.gov/forum/topics/the-short-circuit-theory-keep-or-remove-those-gable-vents

http://www.greenbuildingadvisor.com/blogs/dept/building-science/lstiburek-s-rules-venting-roofs

I am not strongly recommending that the gable end vents be removed strictly due to a "short circuit theory". That said,  I disagree with the first article you posted, regarding the claim that gable vents are harmless, and do not influence the pressure differential, since it appears that they failed to give any weight to wind pressure on the gables of the structure, or the venturi effect of wind pressure over the crest of the roof. Basically, they are probably 100% correct, when gathering data on a perfectly still, warm, sunny day. Which is wonderful, when it happens, but hardly reflects reality. (BTW, my concern on this issue is covered in depth in the comments, where many folks jumped in to question viewing attic venting as simply a "stack" or chimney event, absent the wind issue)

 As the first article mentioned in passing, my primary concern is based on the fact that a combination of fully vented soffits, a continuous ridge vent AND gable vents ,can and will, create a disaster in snow country, if all the wrong conditions occur at once. Lstiburek is one of the greatest minds in the business, and he explains it well in your second link. Balance is not desirable, and  it is more important to have the largest net free area of soffit vent possible while keeping upper venting modest, with less total net free area. Lstiburek explains why excess venting, up high, is undesirable, and I gave some real world experience of what can go wrong. If you are in an area where high winds, extreme cold, and very lightweight snow are not common, then leaving gable vents in place is probably harmless. however, there is no good reason to add them, or install them in new construction if proper soffit and ridge ventilation are installed.