The house was built in 2000. The attic access cover
was missing. No info. for how long the access was missing.
This attic contains two heaters. Half the attic looked great
no mold like substance on the boards. The other half (the
westside) had mold like substance on the trusses…
No evidence that the roof is leaking…Riverside calif. is a
low humidity climate.
Its more black substance then Ive ever seen in the Attic…
Part of me says no worries…Part of me does not want to
chance a problem…
If it looks like mold, smells like mold and tastes like mold, it is mold. If it is mold, it is builders mold. Look at the blocking or strapping clear mark on the wood in the third picture. If it was caused after the house was completed, you would see mold on the sheathing first because sheathing is more porous and contains glue which mold loves to snack on.
That much mold in the attic can cause problems, especially since there is ductwork in the attic.
From a photo it’s hard to tell. However, why some wood members and not others. There is also a beetle called an ambrosia beetle. They leave a stain behind them when they exit the wood. This is in the wood before it’s kiln dried. Make sure the blemish is current and not milled that way. Look at the adjoining wood members and see if there is a consistency to the mosaic.
By only using your comments and photos provided, it sound like the attic has inadequate ventilation that is trapping moisture, either caused by lack of venting or blockage of existing. This can also create hot zones during the summer, and during the winter the under ventilated areas can lead to condensation, mold and mildew. You also mentioned that there was no evidence that the roof is leaking. The moisture maybe coming from the condensation tube or tubes (you mentioned 2 furnaces), they may not be draining properly or leaking.
Like James said, its prolly Mold, looking at the marks when the Trusses were bundled at the factory and tossed off the truck at the job-site the mildew probably formed prior to installation, since the A/C ducts are under positive pressure I wouldn’t say anything besides it looks like the trusses have past mildew on them but their dry now (since I’m sure you checked with a moisture meter), and since nobody is living in the attic (we hope), don’t lose any sleep over it…
If it appears to be excessive levels of mold… and it sure does, recommend a specialist who can pinpoint the source of moisture. What was the level of moisture in the wood when you checked it with a moisture meter? Is it possible that this is from a past leak that has been repaired?
Got to disagree with you on this one, Dale. If the moisture is ongoing and the house is put under negative air pressure by a whole house fan or various other exhaust fans, high concentrations of spores could be sucked into the living space. Not usually a big deal unless one of the occupants has a health problem that makes them vulnerable… compromised immune system, lung disease, asthma, allergies.
It looks Like Organic growth Seeing most of us can not do on site Mold testing. Most likely Truss’s were sitting outside for a awhile… as most said There is strap marks.
I would mention it, and recommend treatment . at least here anyway. with temperature changes Condensation and so on it could activate growth . Some fungus can be as bad as Termites ,The old CYA
Go to Lowes or Home Depot one day and pick through their piles of dimensional lumber. I would guess that 20 to 30% of the lumber will have the same “discoloration.” After all, this stuff is “manufactured” (grown) in climates ripe with “fungal” growth - FORESTS.
