The Trouble with Guarantees and the "Like New" Trap

Mark Cave

Somewhere in your area, there's a competitor with a van that says "100 percent spotless clean guaranteed". Or maybe "five years moss free, or we come back for nothing". It wins jobs. Customers love it. And I'd argue it's one of the most expensive sentences a contractor can print on a vehicle.

Mark Cave

I'm Mark Cave, founder of SoftWash UK. Last time out, I went through 240 things professional softwashing asks you to get right, and I warned about underquoting and splash and dash shortcuts. Today I want to zoom in on two of those topics that sit together: should a softwasher offer a guarantee, and how do you avoid overpromising results?

Mark Cave

Let's start with the biology, because it's the bit the big promises ignore. No exterior cleaning method, chemical or mechanical, permanently stops moss, algae or lichen coming back. Spores are in the air. They land on every property in the UK, every single day. Whether they take hold depends on things you don't control. Shade. Which way the roof faces, because north facing slopes stay damp for longer. Mature trees dropping pollen and leaf debris. Humidity. Rainfall. So when somebody guarantees a five year result, they're guaranteeing the weather, the neighbour's oak tree and the spore count. That isn't a guarantee. That's a gamble with your own money.

Mark Cave

The second problem is water. A lot of staining isn't really a cleaning problem at all. Picture a rendered wall with a dark streak under a leaking gutter joint. Or white salt crust on brickwork because moisture keeps moving through it. You can sanitise that wall beautifully. But chemistry can't mend a gutter. If the moisture source is still there, the staining comes back, and if you've guaranteed it, you've guaranteed yourself an unpaid callback.

Mark Cave

Then there's what I call the like new trap. Softwashing treats biological contamination. It doesn't restore a tired surface. And here's what many contractors overlook: dirt hides things. Once the dark biofilm is gone, you can see chalking paint, peeling render, spalling brick, blown mortar joints, even old wand marks from someone's pressure washer. The customer sees those and thinks, you've done that. If you've promised them a restored, like new finish, you've handed them the argument.

Mark Cave

Roof tiles are the classic example. Concrete tiles have a microscopic cement layer on the surface, often called fines, which seals the sand and aggregate underneath. Marley says in its maintenance guidance that high powered jet washing isn't recommended, because it can damage the surface and reduce the expected life considerably. BMI Redland says on no account should a high pressure water jet be used, because it erodes the surface. And Forticrete says power washing strips those fines and invalidates the guarantee.

Mark Cave

Now think about what that means. A contractor who guarantees an instant, uniform, like new roof is under pressure to chase that result. And chasing it leads to bad decisions. A stronger hypochlorite mix, which can scorch neighbouring planting or etch lime based stonework. Or a turn to high pressure, when what the job actually needed was patience and biocide dwell time. The guarantee doesn't just create risk on paper. It pushes you to do worse work.

Mark Cave

And the chemistry has its own timescales. Sodium hypochlorite oxidises surface biofilm quickly, so you see a change on the day. But it leaves no residual protection against new spores landing tomorrow. A quaternary ammonium biocide, such as DDAC, which is what's in Soft Wash Pro 50, does leave residual suppression. But it relies on rain, sun and wind over weeks or even months to break down and shift dead moss and lichen. Two different tools, two different timelines. Your customer needs to understand which one you're using, and why, before you start.

Mark Cave

So does that mean you never guarantee anything? No. It means you guarantee the right thing.

Mark Cave

You can't promise how a building will look in five years. You can promise your workmanship. That you surveyed the surface and identified the substrate. That you chose chemistry suitable for it. That you followed the label on dilution. That you protected drainage, plants and neighbouring materials. That you worked to recognised standards. Every one of those is in your control, and every one of those you can prove.

Mark Cave

It starts at the quote. Define in writing what finished actually means. Describe the process. Explain the expected timescale, especially if you're using a slow clean biocide. List your exclusions. And please avoid phrases like "restored to new". Existing repairs, coating defects and permanent discolouration won't disappear because you've treated the algae on top of them.

Mark Cave

Photograph the property before you start, including any defects. Point out the leaking gutter before you clean, not after the stain returns. Do a test patch, and explain it to the customer as due diligence, because it protects both of you.

Mark Cave

Then give customers what they actually want underneath the guarantee request, which is peace of mind. Offer an annual or two yearly maintenance treatment, a light biocide wash every 12 to 24 months, depending on the property and its exposure. You suppress recolonisation before heavy biofilm builds up. The customer gets a clean building that stays that way, and you get recurring work instead of one off gambles. Everybody's better off, apart from the lad with the five year promise on his van.

Mark Cave

Here's the bigger point. Every part of this comes back to knowledge. Surveying for defects. Reading a surface properly. Knowing what a product can and can't do. Writing a quote that's clear enough to settle a dispute before it starts. Podcasts like this are a good starting point, but professional softwashing needs deeper understanding of chemical selection, application, safety, compliance and pricing.

Mark Cave

If you'd like structured learning, the SoftWash UK CPD Certified Softwash Training Course was built from years of real world industry experience, to help contractors avoid expensive mistakes and work more professionally. It's online, so you learn at your own pace. Completing it makes you eligible to become an Approved Softwash Applicator, with a directory listing, and it brings you into the National Association of Softwash community. You'll find it at softwashing.uk, and the training details are at softwashtraining.uk.

Mark Cave

So here's a challenge before your next quote. Read your last three quotations and look for any promise about how a surface will look, or how long it will stay that way. Replace each one with a clear statement of what you will do and how. Your workmanship is the thing you can stand behind.

Mark Cave

Thanks for listening, and I'll catch you in the next one.