Facade sandblasting
When the method suits render, clinker brick and natural stone – and where caution is needed.
Read the guideBlasting exposed concrete – shaping surfaces deliberately
Exposed concrete lives from its surface. Blasting removes the top cement layer in a controlled way, evens out patchy areas and, if you wish, reveals the aggregate – from gentle fine blasting to a bold texture.
The basics
What blasting does to exposed concrete
Freshly stripped concrete carries a thin, fine-grained layer of hardened cement paste on its surface – the cement skin. It clearly shows formwork joints, clouding, colour differences and efflorescence. Blasting removes exactly this layer: sand and aggregate appear underneath, and the surface looks calmer, livelier and more even.
How deep the removal goes depends on the blasting medium, pressure, nozzle distance and working speed. The same wall can be lightly brightened or clearly textured. Important to know: removal is final. What is gone cannot be brought back – which is why every exposed concrete project with us starts with a test area.
The options
Fine blasting or coarse blasting?
Fine blasting removes only the cement skin. The surface still looks smooth but becomes more matt and even, with fine sand grains showing. It is the right choice when stains, formwork marks or colour variations should be calmed down without changing the character of the concrete.
Coarse blasting goes deeper: some of the mortar between the grains is cleared out, and the coarse aggregate stands out in relief. The result is a strong, crafted texture – a deliberate design feature for facades, walls and staircases. There are smooth transitions in between, which we define together on the test area.
- Even out formwork joints, clouding and colour variations
- Clean soiled or greyed exposed concrete
- Design textures up to exposed aggregate
- Create a sound, rough substrate for coatings
Honestly
What you should know beforehand
Exposed concrete is a natural material: after blasting it shows what is inside – honeycombing, voids or patches of repair mortar become more visible because their make-up differs from the rest of the surface. We discuss this openly in advance instead of promising a flawless result.
Where the concrete cover over the reinforcement is thin, we blast with restraint, because the protective layer must not be weakened unnecessarily. Edges, chamfers and joints get special attention so they do not break out. And new concrete should be sufficiently cured before blasting – we agree the right time with the site management.
On site
How an exposed concrete job works
We work mobile with our own blasting equipment and compressor – indoors and outdoors. First we assess the surface from your photos or on site. Then we create a test area in an inconspicuous spot, on the basis of which you approve the desired finish.
Before the actual blasting, windows, doors, adjoining components and neighbouring surfaces are carefully masked; indoors we additionally seal off the work area against dust. The used blasting medium is collected and disposed of properly. If the surface is to be impregnated or coated afterwards, we create the right substrate – product choice and application are agreed with you and the contractor carrying out the work.
Frequently asked questions
Frequently asked questions on this topic
In principle yes, provided the concrete is sufficiently cured and sound. What the result looks like depends on the concrete mix, formwork and age – so we always start with a test area before working on the whole surface.
The surface becomes more open-pored and absorbs dirt and water a little more easily than a smooth cement skin. A suitable clear impregnation compensates for this; we are happy to discuss whether it makes sense for your surface.
No – removal is final. That is exactly why we work with a test area and approach the desired finish step by step instead of starting at full power.
Keep reading
Related topics
Blasting media compared
Mineral media, glass beads, corundum and more – properties, selection and environmental aspects.
Read the guideWhat does sandblasting cost?
The key cost factors honestly explained – and how to get a firm quote quickly.
Read the guide
Free & no obligation
Exposed concrete that should look better?
Send us photos of your surface – we suggest a suitable finish and give you a firm quote including a test area.