Mold on mortared walls
kjmass1| Posted inGeneral Questionson
I noticed some white mold in parts of my unconditioned, detached garage/shed. It is built on slab, with a double row of brick walls, with a mortar parge coat on the inside. Roof is 4” concrete slab as well. One updated window and a double wide carriage door that has a healthy leak gap on the bottom.
Today with the warm rains, the interior walls are 38 degrees and damp.
Anything I can do to prevent the mold and moisture? Keep the window open so the interior temp more closely follows the exterior? Also need to keep in mind bricks have popped before when inside is damp and temps crash below freezing. Exterior has been sealed and will bead water well.
Kevin
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Replies
Mold needs food and moisture to grow. Condensation will occur on surfaces that are below the dew point, so cold surfaces in a warm room, basically. If you can get your shed indoor ambient conditions to match the outside, that should reduce or eliminate condensation, except for what occurs naturally as the day warms up (think dew on morning grass). You’d still have the humidity issue though.
There are paints that are supposed to be mold proof. You might try painting your walls with one of those paints to eliminate the “food” part that mold needs to grow. My guess on mortar walls is that the mold is using dirt/dust as food, so a good pressure washing of the walls might be all you need to keep the mold away, at least for a while.
Bill