Why is my home's masonry looking chalky? Contractors reveal the cause, how to easily restore it before winter, and when this residue is a warning sign

Recently, I looked up at my home’s exterior and noticed a white, chalky residue all over the extensive red brickwork of my relatively newly built home.

It was, in fact, visible in patches on most sides, and I was a bit alarmed. After speaking with contractors and brickwork experts, I’ve learned that this is a natural reaction when living in a humid and rainy region, as I do. As minerals in the brick are drawn to the surface by moisture, it can be easily remedied, the pros tell me, with F9 Efllorescence cleaner, available at Amazon.

However, there is a time when this is a warning for a fall home maintenance task you need to address right away.

What is efflorescence and how do you remedy it?

I asked experts what the residue is, and Randy Dewey, owner of First Choice Exterior Cleaning, says, 'You're dealing with efflorescence, which is a white, chalky substance that can form in brick or pavers over time. When water hits the brick surface and evaporates, the dissolved salts form crystals, which creates the visible white residue you see.

'It can occur in any area and is typically caused by constant contact from irrigation systems, or high amounts of rain.'

Randy reassures that the substance won't cause any structural problems, but warns, 'If it's not cleaned promptly, it can be hard to get off and can be a significant indicator of a moisture issue within the wall itself if it continues to come back after cleaning.'

He recommends cleaning the chalky residue in the first instance with F9 Efllorescence cleaner, available at Amazon, adding that you will need to 'use this in conjunction with a pressure washer. Follow instructions and you'll have an efflo-free wall.'

Homes & Gardens' home tech editor Dan Fauzi recommends the 'great value' Homshade Electric Pressure Washer from Walmart, as it's 'rare' to find one with 4200PSI at its price point. They also love that it includes a foam cannon, gloves, and a 120-degree nozzle for versatile usage.

If the efflorescence on your home correlates with the typical weather you experience in your region, it shouldn’t be a problem in the long term. To prevent wet weather or regional high humidity from continuing to draw the natural salt out of your brickwork, seal your bricks or pavers with a good-quality sealant.

Rain Guard Water Sealer, available on Amazon has a clear natural finish. A product like this will, over time, protect the integrity of your exterior brickwork, whatever the weather.

The one caveat

However, if you live in a generally hot and dry region, your gutters are clear, and there is no other reason for this buildup, then the mineral deposits may well be a silent warning sign that there is a leak in your home.

Efflorescence that returns after cleaning without outside factors can be an indicator of moisture coming from inside the house, be it through the structural gaps in your home’s framework, as a result of leaks that have led to mold in your insulation, or hidden interior leaks evaporating through your home’s brick facade and bringing its salt to the surface.

Ron Shimek, president of  Mr. Handyman, a Neighborly company providing commercial and residential property maintenance, repair and improvement, adds, 'Recurring efflorescence may be an indicator of a moisture problem in your home.

'This can cause more serious issues such as mold, mildew and structural damage. It is important to find and eliminate the source of moisture, such as ensuring proper drainage or sealing cracks.'

If this is the case, you’ll need to call professionals, such as a remediator, to assess your home and locate the source of the water egress.

In the meantime, if the chalky residue is limited to one area of your brickwork, you might be able to track down the source by checking windows, doors, and roofing in that particular area for gaps, cracks, irrigation issues, or damp.

It's worth cleaning your gutters as well, in case debris is causing rainwater to spill over and down your home's brickwork, instead of going down the drain as it should.

Whilst a bit on the pricier side, a handheld thermal imaging device, available from Amazon, can help you locate leaks yourself. This device can also come in handy later if you suspect a pipe has burst in cold weather, or if you’re experiencing a sudden loss of water pressure, which can indicate a hidden leak.

As for my home's brickwork, the salt accumulation correlates with the high humidity and rainfall of the region I live in, but I can also see from the chalky areas that my gutters may be partially blocked.

I will be sorting that out to avoid home maintenance mistakes this winter and protect my biggest investment: My home.

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Next, learn more about the common leaks that can occur in a house, and how to spot the warning signs that you have mold in your plumbing.