Mold and mildew growth.
Mold mildew underside of roof.
The common denominator between algae mold moss and mildew is that all are the products of damp settings.
Mildew growth is likeliest to occur in warm wet environments and often spreads on roofs with poor drainage.
The most common reason why mold tends to grow in these areas is inadequate ventilation of the attic.
Generally tearing off a roof and roof sheathing and perhaps roof framing to remove mold would not be sensible nor cost justified.
The moist hot air inside the attic makes the perfect breeding place for the mold which quickly attaches to the underside of your roof and begins to spread.
After several years of this there may be.
Remove moss mold mildew and algae with a safe gentle cleaning product compatible with your roof like wet forget outdoor hose end.
In the vast majority of cases the mold growth is caused by condensation.
The standing water and humidity the rapidly growing spores and wood rot these are quick and fertile breeding places for mold.
Why black mold is bad if black mold is so common in attics and roofs is it really bad.
More so than other harmful growths mildew spreads fast.
It requires no pressure washing scrubbing or use of harsh chemicals that could damage your roof.
As you can see the alga gets on your roof easily enough the wind just has to blow in the right direction and there it is.
If you have mold covering large sections of sheathing all over the attic the culprit is.
Mold growth provided it is not just cosmetic mold which can simply be left alone can be cleaned from wood surfaces by blasting scrubbing or even simple surface wiping depending on the surface accessibility and smoothness.
After that an annual cleaning especially for exterior and depending on your location will probably be required.
Just as easily mold and mildew follow.
If you plan on painting the ceilings etc you can get a mold and mildew preventative added to paint.
Heavy rainwater weakens and damages the roof even further.
It rarely lasts the full 5 years but if you clean prior to painting it ll get you pretty close.
Wet forget outdoor cleaner only needs to be applied once a year to remove the growth.
Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest.
Until you take steps to keep dew from forming on your screens the mold will keep growing on your porch.
Moisture and water can get in to your home through the holes in your roof and down to the wood underneath.
If mold spreads to the ceiling of the porch the wooden boards that support the roof can eventually rot and cave in especially if it rains a lot in your area.
This occurs when the temperature of the sheathing drops below the dew point creating a thin layer of moisture on the substrate.