What happened here???

Yesterdays inspection has me a little baffeled. Under eave storage space sheathing has a lot of mold on some sheets and little to none on others, not only that but, some of the sheets are bowing up and of these sheets, some have cracks in them but are not rotted.

The seller states the prior roof did leak, but since covering with metal he has had no problems. The soffit venting looks acceptable, the ridge venting could be improved (picture showing insulation), but air is moving.

The roof system is a 2x8 truss system spaced 2’ O.C… The metal roof was installed over 1 layer of asphalt shingles. I have never seen the sheathing bow up (out) like this and also have these splits.

Any ideas/recommendations.








It looks like smoke damage, rather than mold to me.

When I first saw it I thought the same thing, but when I looked at it closer I could see the “star” shaped coloinies. I don’t think it’s fire damage.

Scott, what size thickness was the plywood and where there h clips?

Well Scott maybe some mold grew from the water applied in the attic after the fire was extinguished…:wink:

Hi. Scott;

Looked at your photos of your Inspection, and have a few un-answered questions of my own. This is unusual.

The cracked plywood to me looks like it was hit and broke the bottom layer, possibly due to a thin layered plywood and bundles of roofing dropped to hard when done initially, or when the metal was done.

I see that there are no H-clips visible in two of the photos and the dark stained underside of the sheathing was definitely cause by heat loss during the Winter months and continuous frosting and thawing over the years. I have seen this before up here in my area.
The insulation appears to be of only an R-19 and storage in the attic might have negated it’s insulating qualities.
No proper vents were installed and one picture is showing the insulation stuck to the underside of the roof sheathing which is another indicator of frost on the underside of the sheathing during the Winter months.

I am also surprised to see a dwelling of this size approx. 28’ wide with a 6/12 pitch roof with 2"x8" trussed rafters.
A House this size with 2"x8" trussed rafter would only tell me this is a full walk-in attic from somewhere, possibly walk up stairs or fold down stairs where more heat loss is occurring. The furniture at the gable end would indicate that the attic was used for storage. The 6/12 pitch roof would have given them approx. 7’ 0" of head room.
Walk through attic truss design have increased rafter sizes due to the configuration.

Was there bathroom vents and dryer vents discharging in the attic?

One more puzzle, if the roofing shingles were left under the metal roof, why do we not see the nailing pattern penetrating the plywood.???

Hope this helps in solving your problem or I made it worse. ha. ha.

Marcel :slight_smile: :slight_smile:

Mold looks like this all of the time. We see much of this during complete roof tear-offs with decking replacement.

The insulation, besides not having baffle chutes installed along the eaves, looks in some/most of the places, to be pushed tightly in place to the soffit area. The soffit vents may or may not be adequate, but they are not even minimally functional if they are not allowing an equal or greater than volume of fresh air intake for the amount of hot air exhaust.

The cracked decking looks like someone hoisted and dropped or just overloaded the bottom sheets of decking with on of the previous roofing materials. I clearly do not see the original shingle nails piercing the decking as I woud expect, every 5" course up going across horizontally, with the 2 end nails being about 3" to 4" apart and the 2 center shingle nails being 12" apart from each other and from the end nails.

I seems as if there is a desk with a battery laying on top of it, so some activity does occur in this area, at minimum for walk-in storage, with a large enough access area for the desk to fit through.

Lets re-cap:

  1. Previous roof leaks.
  2. No roof mremoval, but a layover with a sheet metal roof.
  3. Ventilation is inadequate and/or blocked, minimally along the entire length of the eaves or soffits.
  4. Negligence during loading of previous roofing materials, which were never attended to when it occurred.
  5. Bowed decking indicates expansion and contraction cycles, which stress out along the vertical butt edges. Therefore, too much internal humidity is being absorbed creating the bowing and as a secondary consequence, the underdeck side mold growth.
  6. As previously pointed out, no visual of H-clips, further exasperating the horizontal bridging as well.


Mold does not look like this all of the time.!!!
Mold needs food, moisture, and temperature, figure it out.
Eliminate one of them and they do not survive.
Frost, thaw, moisture, food, frost, thaw, moisture, food, and finally Summer.
Ahhh, but now the plywood looks like sh$it.:slight_smile:

Get it??

Marcel :slight_smile: :slight_smile: :wink:


I would give you and Dale green but it’s telling me I have to spread it around before I give you and Dale green again!!!

Great post Marcel!!!

Great post Dale!!

Correction being made for those that needed to pick my nits.

I should have stated;

I see mold that looks like this on a regular basis.


I see mold that looks like this all the time when we are replacing the decking.

AND: What does “Giving somebody a green” mean?

Is it an honororium badge?


I don’t need no stinkin badges.

I just felt so excluded, I had to vent. Don’t want mold to grow inside, now, do we?


The cracked plywood is through atleast 2 layers maybe 3.

There are no H clips present.

I would say the decking is atleast 1/2".

The attic space (under eave storage) is on both sides of a bedroom which have regular stairs (or somewhat irregular here).

There is no bathroom or dryer venting here, they go directly outside.

The insulation is R-19.

The shingles do have an irregular pattern, it looks like only the edges of each shingle were nailed down, maybe that is why the roof started leaking on him.

There is some proper venting, but clearly not in every bay.

More comments?

So, what would you guys recommend I write on the report. Do you think the roof will hold up, should the sheathing be replaced, what about the missing “H” clips. What can be done about the missing “H” clips at this point?


Ventilation is substandard in the attic. Inadequate attic ventilation may cause moisture build up in the colder months resulting in the growth of mold and in high attic and roof surface temperatures in the summer.

With a metal roof there is no need to report the H-clips, I would suggest they have the attic tested for mold, also with a metal roof the cracked plywood is not a big issue, if this is the only 2 places that is cracked…

You have inadequate ventilation and/or interior air leakage into the attic (where do your ventilators terminate?).

The metal roof will cause the roof to be even cooler than it has in the past and this condition will likely worsen.

I see no reason to test for mold as the attic is an outdoor space. It’s pretty obvious that is an organic substance that is going to deteriorate the wood materials. What are you going to do when you determine that it is in fact a mold? You’re going to have to ventilate and seal air leakage into the attic.

If you’re going to test for something, test for something worthwhile. An IR inspection during the heating season this fall will identify the location/sources of conditioned air entering the attic so they can be sealed.