In short: Pressure washing brick is enough for fresh, light dirt on hard, new brick. With old, soft brick, soot, black deposits, paint and graffiti, a pressure washer often does harm: it washes out the joints, strips the top layer of the brick and lets water into the wall. Laser cleaning works dry, removes only the dirt and leaves the brick intact. The safest way to decide is after a test on a small section of the facade.
How does washing brick differ from laser cleaning?
Washing removes dirt with water, often at high pressure, sometimes with added chemicals, while laser cleaning vaporises the dirt with light, without water and without touching the brick. When washing, the force of the jet acts on everything on the wall: on the dirt, but also on the brick face and the mortar in the joints. The laser is set so that the energy is absorbed by the layer of dirt, not by the clean brick underneath, so the process stops at the boundary of the original surface.
When is washing brick enough?
Washing with water makes sense when the brick is hard and in good condition, and the dirt is fresh and superficial. This is often the case on newer facades of clinker brick where dust and light street grime have settled. If there is no soot, paint or old, ingrained deposits and the joints are intact, gentle washing is often the cheapest sensible method. In that case we tell clients honestly that the laser is not needed.
When does washing damage brick?
Pressure washing mainly damages old, soft brick and facades with weakened joints. The most common problems after a pressure washer:
- stripped brick face: the jet wears away the top, fired layer, the brick becomes porous and picks up dirt and moisture faster,
- washed-out joints: old lime mortar cannot withstand the pressure, and the gaps then have to be filled,
- water in the wall: the wall soaks up water, and moisture before winter means a risk of frost damage,
- efflorescence and streaks: water draws salts to the surface, and white deposits appear on the brick,
- chemicals: acidic and alkaline products can discolour brick and leave salts in the wall.
We write more about chemical products in the article laser vs chemical cleaning.
What dirt on a facade does the laser remove?
The laser removes soot, black atmospheric deposits, old paint, graffiti, plaster residue and biological growth such as algae and moss from brick. It also copes well with detail: profiled cornices, window surrounds, ornamental brick and joints that cannot be safely cleaned with a water jet or abrasive. Here is our brick and facade cleaning service. What it does not do is give brick back a surface it has lost: if the face has already been destroyed by earlier cleaning, the laser will clean it but not rebuild it.
Won’t algae and efflorescence come back after laser cleaning?
The laser removes deposits from the surface, but it does not remove the cause if the wall is constantly damp. Algae, moss and salt efflorescence come back where water rises into the wall, leaks from a gutter or sits on a cornice. That is why, before cleaning, it is worth checking where the moisture comes from and fixing it. After laser cleaning the wall is dry straight away, because we use no water in the process.
Is laser cleaning suitable for a historic facade?
Yes, laser cleaning is one of the safest methods for historic brick, because it does not abrade the surface or put water into the wall. On historic buildings the scope and method of cleaning are set by the conservator in charge of the work, and a building listed in the register of historic monuments needs a permit from the regional monument conservator. We carry out laser cleaning according to these decisions. More: laser cleaning of historic monuments.
How much does laser cleaning of a facade cost compared with washing?
Washing a facade is usually cheaper per square metre and laser cleaning more expensive, but the laser carries no risk of destroying the brick and joints. We charge for laser cleaning by the work of the system with an operator: from PLN 250 net per hour (continuous-wave CW laser) and from PLN 380 net per hour (pulsed laser), less for longer projects. How many hours a facade takes depends on the type and thickness of the dirt, access (scaffolding, lift) and the amount of detail. That is why we do a test on a sample before quoting. When calculating the cost of washing, it is worth adding any repointing and efflorescence removal that may be needed after the water. Details: how much does laser cleaning cost.
Washing, sandblasting or laser: which to choose?
The choice depends on the brick, the type of dirt and how much risk you can accept:
- hard, new brick, light dirt: gentle washing is enough,
- old or soft brick, soot, black deposits, paint, graffiti: laser cleaning,
- detail, cornices, ornamental brick, historic building: laser cleaning, to the scope agreed with the conservator,
- a large, smooth surface with no historic significance, where roughness does not matter: compare the costs with sandblasting, which we describe in the article laser cleaning or sandblasting.
If you do not know which group your facade belongs to, send us a photo. We will tell you whether the laser makes sense here, and if washing is enough, we will tell you straight.
Frequently asked questions
Can brick be washed with a pressure washer?
Hard, new brick with light dirt, usually yes, at moderate pressure. Old, soft brick and facades with weak joints are often damaged by a pressure washer: it strips the face and washes out the mortar.
Does the laser remove paint and graffiti from brick?
Yes. The laser removes paint and graffiti layer by layer, without chemicals and without abrading the brick. We check the result first on a small area.
After laser cleaning, do you have to wait for the facade to dry?
No. Laser cleaning uses no water, so the wall is dry straight away and you can move on to the next work.
Will the laser destroy the joints?
Not with well-chosen parameters. The laser cleans dirt on the joint the same way as on the brick, without washing out the mortar.
Where do you clean facades?
Our head office is in Plewiska near Poznań, with a branch near Inowrocław. We work in Poznań, Inowrocław, Bydgoszcz, Toruń and the surrounding area, and travel across Poland for larger jobs.
Do you have a dirty brick facade?
Send a photo of the surface to biuro@omme.pl or via WhatsApp. We will tell you whether the laser makes sense here and arrange a test on a sample. Phone: 570 471 653. See also: laser cleaning of brick and facades.
