Thread: what is the white stuff on deck boards

1985 detached home, the attic ventilation is good but had mositure stain on deck boards, not too bad. The roof was layered about 10 yrs ago. I just didn't get the white stuff? Have they done something for the moisture boards?

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No soffit vents.
Ice daming can create staining at lower areas either because the weather shield is not present or extended far enough up.

Wind driven exhaust vent may be pulling too much air up out of house as there are no soffit vents. How many of that type are installed? I can only see one in the picture. Depending on who you listen too these turbines can create more problems than they fix.

What was the skylite well like as view from the room below? Was there any staining, damaged drywall?

White areas almost appear as if someone had a spray can - random and odd shapes.
If the white areas where fuzzy in nature you may have mould?

Originally Posted by Raymond Wand

No soffit vents.
Ice daming can create staining at lower areas either because the weather shield is not present or extended far enough up.

Wind driven exhaust vent may be pulling too much air up out of house as there are no soffit vents. How many of that type are installed? I can only see one in the picture. Depending on who you listen too these turbines can create more problems than they fix.

What was the skylite well like as view from the room below? Was there any staining, damaged drywall?

White areas almost appear as if someone had a spray can - random and odd shapes.
If the white areas where fuzzy in nature you may have mould?

no exhaust vents, no ice daming at mild climate, skylite well ok, looks like powdery white

Okay, so you would have to have it tested to confirm its mould.

The venting appears to be a no-brainer.
If there was capillary action through the shingle mat the plywood would be black.

Mold would have mycelium. If you rub the hyphae, it breaks down and almost disappears.
Did to move your fingers over the mycelium?

It looks like white spray paint. The mould stains may have been sprayed.

Bucket in the attic, evidence of a roof leak. No water in the bucket? Then its just old junk in the attic.

Grasshopper,

If there is no bucket, is there still a leak?

I agree with John, that look like spray paint!

There is suspect organic growth and staining.
Zoom in on the fibreglass fill closest to the roof eave.
one.jpg

looks a lot like the powder (boric acid?) that some exterminators use. I often see it at sill plates and band joists. Just a guess.

Does not look like mold.

Originally Posted by Peter Louis

1985 detached home, the attic ventilation is good but had mositure stain on deck boards, not too bad. The roof was layered about 10 yrs ago. I just didn't get the white stuff? Have they done something for the moisture boards?

Peter, what type of venting did the attic have , please?
You mention in your post "the venting looks good" but I disagree.
Explain what you observed. I for one see no "eave venting or baffles."

Fibreglass fill was blown into the roof eave cavity.
I see gables. Were there gables vents?
Thirdly, a round vent protruding upwards leads me to believe a turbine is in place.
The upper roof deck substrate is clean plywood while the lower plywood appears blackened.

Awaiting your reply.

Originally Posted by ROBERT YOUNG

Peter, what type of venting did the attic have , please?
You mention in your post "the venting looks good" but I disagree.
Explain what you observed.

1: I for one see no "eave venting or baffles."
2: Fibreglass fill was blown into the roof eave cavity.
3: I see gables. Were there gables vents?
4: Thirdly, a round vent protruding upwards leads me to believe a turbine is in place.
The upper roof deck substrate is clean plywood while the lower plywood appears blackened.

Awaiting your reply.

Hi, Robert

I mean roof venting. baths have no exhaust vents. 1980s house. yes, roof leak at busket. Yes lower part of sheathing has water stains or condensate damage. no gable vents. only eave and roof vents. I suspect the attic ventilation was not good. Then they installed whirlybird.

Thank you.
Three-way venting is eliminated.

Peter, to say the roof venting is OK to me means, "there's a hole or holes in the roof."
So one part or the venting systems equation has been completed, ...hopefully.

Now,...the whirlybird as you call it has a formal name. A roof turbine vent.
The hypothesis behind the going to be noisy contraption, create a negative pressure when rotating.
I guess the adage "the squeaky wheel gets the grease" never crossed the inventors mind/s while jotting down their Ericka moment.

I had many discussions with a colleague, Brian, McNeach ..., about the contraptions ability to increase the air flow in an attic ha ha ha.
From what I read from venting documentation, a ><5% was added, including insomnia at no added cost to the homeowner.

Peter, are the eave soffits allowing free air exchange?

Originally Posted by ROBERT YOUNG

Thank you.


Peter, are the eave soffits allowing free air exchange?

Yes, looks ok. I suspect it was a grow op but no other clues

Originally Posted by Peter Louis

Yes, looks ok. I suspect it was a grow op but no other clues

Many mean/meant to say, "no other clues that one/could/would recognise."
There are clues if one knows what to look for and where to look.

Originally Posted by Peter Louis

1985 detached home, the attic ventilation is good but had mositure stain on deck boards, not too bad. The roof was layered about 10 yrs ago. I just didn't get the white stuff? Have they done something for the moisture boards?

Am I missing something?
Looks blocked to me.
vent.JPG