Moldy Plywood Under New Roof

Moisture may indeed be unevenly distributed under a roof depending on exactly how air is moving variations in baffles insulation wind direction soffit openings ridge openings blocking etc.

Moldy plywood under new roof.

All cause those effects. Hello i got brand new gaf roof with cobra roll off ridge vent back in april 2015. If the old plywood was clean and not infested with dry rot or mold it should be ok to cover it with the new plywood. Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest.

Easily kill mold with a vinegar spray. Mold on the underside of roof sheathing is also very common. Professionals use steri wiping which takes care to avoid spreading moldy debris by always folding and using a clean side of the wipe when moving to a new spot. But that s normal with soffits the underbelly of the roof.

One thing to consider is that the new plywood probably wants to be the same thickness as what would be used if it was used by itself on the rafters i e. Ron mold likes to grow where there s moisture on mold friendly surfaces. Where the framing lumber is indoors or otherwise in a location where water spillage is a concern wipe the areas of heaviest mold to remove any loose mold from the surface of the lumber. Mold usually grows due to excess moisture in the area either in the air or on a surface.

I have also had various opinions on the way to insulate after removing the mold. If the old plywood had been removed. The actual attic has only floor insulation and no insulation on the underside of the roof. This occurs when the temperature of the sheathing drops below the dew point creating a thin layer of moisture on the substrate.

The presence of mold in your attic is often the result of poor ventilation insufficient insulation moisture from a roof leak or improper venting from your bathrooms or kitchen. I went up in the attic march 2016 found white mold later i found out the roofer did not cut any soffit eaves vent so they come out cut 50 holes 4 diameter 25 in each side he also told me to spray with mold. Mold that grows on the underside of roof sheathing due to ideal mold growth conditions being present. Some say baffle and reinsulate and others say tear off the insulation under the roof and insulate only the outside of the kneewalls and the floor of the side attics.