Brick Mold Removal
You can prevent mold growth and efflorescence on this chimney with application of a strong water repellent.


Do you feel winter in the air? Take advantage of the last few weeks of mild weather before the cold sets in for good. One project to cross off your list before the cold weather sets in should be cleaning your masonry. It is especially important to clean your masonry if mold is growing on it will hold water.  As the temperatures fluctuate over the next few months the masonry will begin to crack. This is due to the water freezing and thawing. Additionally, it can leave behind white, powdery on the surface of the brick called efflorescence. Efflorescence occurs when water traps inside the brick. As that sun hits the brick and the water evaporates, the salts inside the masonry push to the surface.

Power washing your masonry is not what I would recommend for removing vegetation. This troublesome growth is unsightly but not difficult to remove by any means. Should you elect to power wash, keep the PSI under 3000. Power washing often chip brick that is weak and causes more damage than good. Muriatic acid is also not what I would recommend for removing the mold. This is because this powerful acid has the tendency to stain your brick. This will leave you with a more permanent unsightly mess than the mold was in the first place. This can also lead to efflorescence.

When we go out to clean a masonry surface, whether a chimney, a wall, or a section of the home, we evaluate the integrity of the brick to see what is causing the growth.

Brick Cleaner
This cleaner is safer than muratic acid and works effectively against mold, dirt, moss, rust, and other stains.

Brick structures are constantly damp or near standing water have a higher likelihood of mold regrowing.

To clean mold and other unsightly stains from masonry, I recommend the ChimneyRx Safer Masonry Cleaner, which is deemed”Safer” because it is less corrosive than muriatic acid which can eat away at skin, clothing, and the brick itself as well as leave behind unsightly stains after the mold has been removed. The Safer Masonry Cleaner has easy application and has taken care of even the toughest mold growths we’ve seen yet.

After removing the mold, it is keen to waterproof the area. Obviously, this area has proven it is likely to retain water to the point where mold can flourish. A water repellent that fills the pores of a brick surface and prevents vapors from trapping beneath the sealer is preferable. Areas that hold water constantly or sit adjacent to standing water must be water proofed due to the extremely high likelihood of mold regrowth. If the area that you are experiencing the mold is horizontal, you MUST water proof because the water that stands on the ground after rainfall will almost certainly cause the mold to grow again.

Clay Lamb
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8 thoughts on “Brick Cleaning Before Winter

  1. I see white on my chimney on the bricks. what is this? And will the SaverSystems Safer Masonry Cleaner, clean this off of my chimney?

  2. Usually white substances on your chimney’s brick exterior is efflorescence. I think that what you are describing is efflorescence, which is caused by water sucking out salts from the brick and depositing them on the exterior of the brick. We recommend SaverSystems Safer Masonry Cleaner for cleaning efflorescence off of chimneys due to its relatively safe formula and ease of use.

  3. What water repellent do you suggest to use after cleaning the brick with chimneyRx safer masonry cleaner?

  4. Hi Clay,
    We had our chimney cleaned recently and asked the contractor about cleaning some mold on the north side of chimney exterior. The chimney sweep we used said he did not do that work. Should I ask another sweep or should I be looking for another type of contractor? The chimney is quite high on a multi peaked roof, which is why I’m not going to attempt it myself.

  5. Thanks for explaining that masonry needs to be cleaned to avoid cracking from fluctuating temperatures. I really like the idea of having a brick patio added to our yard. Your article helped me feel prepared to care for the masonry after it’s installed!

  6. I think you answered your own answer, the first guy choked because of the nosebleed altitude which is not uncommon. I think your using common sense not to go on that rooftop. I would contact a number of other chimney contractors but while youre doing it, check theyre working compensation if it’s current! We do many jobs like this with serious scaffolding setups!

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