Should We Use Brick Creams? – Can I Just Ask? – Ep.12

Should We Use Brick Creams?

When it comes to moisture management in masonry buildings, especially older ones being retrofitted, brick creams are often floated as a go-to solution. They promise a lot: less water getting into your walls, no change to how the building looks, and crucially, the ability to keep walls breathable. Sounds ideal, doesn’t it?

But, as with most things in building conservation and retrofit, the truth is a little more nuanced. These treatments have evolved over time, and while they certainly have their uses, they’re not a one-size-fits-all answer. Nor are they free of risk.

So, what are brick creams, and when should we actually be using them?

You can find out the answer to that question by reading on, or if you’d prefer; just click play on the video below to listen to Chris and Andy from our technical team talk through the same question in episode 12 of Can I Just Ask? 👇

What is a Brick Cream?

A brick cream is a hydrophobic treatment—essentially a water-repellent cream—made from siloxane polymers. It looks a bit like hand cream, and it works by soaking into the surface of brick, stone, or render and lining the pores with a water-repelling layer. The idea is to reduce water ingress without completely sealing the surface. Ideally, this means rain is kept out while vapour can still escape.

Earlier formulations tended to block pores entirely, which sometimes caused more problems than they solved. But the modern versions are more refined. Rather than forming a surface film, they penetrate the masonry, typically around five to ten millimetres deep, and coat the pore walls. This approach helps reduce liquid water absorption without totally stopping vapour movement.

Application is straightforward with a brush, roller, or spray, though you do need to be thorough. Because the treatment is invisible once dry, it’s easy to miss spots, and continuity is important. Miss a patch under a chimney stack, say, and you may inadvertently create a runoff path that dumps more water onto untreated areas below. Not ideal.

Where They Shine

Brick creams can be genuinely useful, particularly in retrofit projects where internal wall insulation is being added. By insulating the inside of a solid wall, you reduce the heat moving through the masonry, which in turn reduces the wall’s drying potential. If that same wall is also exposed to driving rain, you could end up with a damp problem that wasn’t there before.

In those situations, a hydrophobic treatment can help tip the balance back in your favour. By reducing how much rainwater gets absorbed in the first place, you give the wall a better chance of staying dry, despite the changes to its thermal behaviour.

They can also be helpful on very exposed façades, parapets, chimney stacks, anywhere that sees regular saturation but doesn’t justify a more radical intervention. Because the treatment is clear and doesn’t alter the look of the wall, it’s often considered acceptable for use on historic buildings, too, where visual impact is a major concern.

The Catch

So, why not just slap it on every wall and be done with it?

Well, there are a few reasons to tread carefully. First, once it’s on, it’s more or less irreversible. You can’t wash it off. That’s fine if it works as intended, but if you’ve applied it in the wrong context—or if the formulation turns out to be less breathable than promised—you’re stuck with it.

Second, it doesn’t last forever. Exposure to sunlight, pollution, and general weathering will eventually degrade the hydrophobic coating. Depending on the product and conditions, you might be looking at reapplication every decade or so. Not a huge burden, but one that building owners need to be aware of.

There’s also the issue of water runoff. A treated wall sheds more water, which can mean more splashback at ground level or concentrated drips onto lower sections of untreated masonry. In some cases, the treatment ends up protecting one part of the building at the expense of another.

And crucially, brick creams aren’t magic. They won’t fix rising damp, won’t waterproof a structurally unsound wall, and won’t make up for poor detailing. If the building has other issues like, failing gutters, cracked pointing, missing flashings, those need sorting first.

So, Should You Use One?

If you’re working on a retrofit with internal wall insulation, or you’ve got an exposed masonry wall that’s otherwise in good nick, then yes – a brick cream might be a sensible part of your strategy. It’s not a cure-all, but it can help reduce the risk of moisture problems developing after other interventions have changed the building’s performance.

Just go in with your eyes open. Choose a high-quality, breathable formulation. Make sure the wall is dry and sound before application. Apply it thoroughly and evenly. And, importantly, understand that it may need renewing in the future.

In the right hands, and under the right circumstances, brick creams can be a genuinely helpful addition to the toolkit. Just don’t expect them to do more than they’re designed for.