High-Pressure Water Jetting & Pressure Washing

Pressure washing has a poor reputation in conservation circles, and mostly it deserves it — a lot of damage to old buildings has been done by somebody with a jet lance and good intentions. But on the right surface it's simply the best tool available: nothing else cleans a thousand square metres of car park deck in a day, and nothing else lifts ingrained traffic grime out of concrete as thoroughly.

The skill is knowing which surfaces qualify. Modern concrete, tarmac, block paving, steel and sound engineering brick can take the force. Soft stone, lime mortar, render and anything painted cannot. We assess that before we set up, not after — and when the answer is that jetting is wrong for the material, we say so and use steam instead.

Pressure, flow and heat — the three dials

People talk about pressure washing as if pressure were the only variable. In practice we're balancing three, and the mix changes the result completely.

Pressure is the impact force at the surface — it's what breaks the bond and it's also what does the damage if you get it wrong. Flow is the volume of water moving through, which is what actually carries the loosened dirt away; a high-pressure, low-flow setup cuts into a surface without rinsing it, which is how you end up with stripes. Heat does the chemical work, and hot water will shift greasy and organic contamination at far lower pressure than cold water needs.

Getting that balance right is the difference between a car park that looks evenly cleaned and one covered in lance marks. It's also why we can often drop the pressure substantially by turning the heat up instead — gentler on the surface, same result.

Rotary flat-surface cleaning

For any large flat area we use a rotary surface cleaner rather than a hand lance. It's a shrouded head with jets on a spinning bar, run flat across the surface at a fixed height. Because the stand-off distance and the speed are consistent, the coverage is even — no stripes, no missed strips, no zebra pattern left behind when it dries.

It's also far faster, and it keeps the water and debris inside the shroud instead of spraying it across parked cars and shopfronts. On a live retail car park or a service yard that matters as much as the finish does. We follow up with a hand lance around edges, kerbs, bollards, drainage channels and anywhere the rotary head can't reach.

• Multi-storey and surface car parks — decks, ramps, bays, stairwells
• Service yards and loading bays — traffic film, spillage, rubber
• Precincts, footways and pedestrianised areas across town centres
• Bin stores and refuse areas, usually with a degreaser and sanitiser
• Industrial hard standing on estates and business parks

Water, run-off and doing it responsibly

Jetting uses a lot of water and it all has to go somewhere. On a car park deck or a service yard that water is carrying oil, rubber, silt and whatever else was on the surface, and letting it run into a surface water drain is both bad practice and a pollution offence. This is the part of the job most quotes quietly ignore.

We plan run-off before we start: where the falls are, which gullies are surface water and which are foul, and whether we need to bund, mat or vacuum-recover. On sensitive sites we use containment and recovery so the water is captured rather than released. If a job genuinely can't be done without controlling run-off, we'll tell you at quote stage rather than discovering it on the day.

We work with our own bowser, so we're not relying on your supply, and we can give you an indication of water volumes if you need it for a site induction or an environmental method statement.

What jetting will and won't fix

It's worth being straight about outcomes. Jetting removes what is sitting on top of a surface, and it removes it very well. What it can't do is reverse damage that has already happened to the material underneath.

Concrete that has been stained by oil for ten years will come up dramatically better but may keep a shadow, because the oil is in the pores and not on the face — that's a job for a poultice or a specialist degreaser, and sometimes the honest answer is that a ghost remains. Block paving that has lost its jointing sand will need re-sanding afterwards. Tarmac that has oxidised to grey won't come back to black, because the colour loss is in the binder. A surface that was patched in three different mixes will still look patched, just cleaner.

We'd rather set that expectation at the quote than have you disappointed at handover, so we say it up front and show you a test patch wherever there's any doubt.

Planned cleaning beats reactive cleaning

Most of the hard standing we clean is on a cycle rather than a one-off — quarterly, twice-yearly or annually depending on footfall and how visible it is. There's a straightforward reason: contamination that gets cleaned regularly never has the chance to bond, so each visit is quicker and the surface never reaches the state where it needs an aggressive clean to recover.

The same logic applies to budget. A planned maintenance programme is easier to get approved than a series of unpredictable reactive jobs, and it means the site is presentable at the times of year that matter to you rather than whenever somebody complains.