Facade cleaning for render, brick and insulated walls – Northern Germany, Sweden and Denmark

Facade cleaning removes algae, green and red growth, fungal spots, dust and dirt deposits from exterior walls – gently enough that render, brickwork and the existing paint are not harmed. It brings back the original colour of the house and is the necessary first step before any new coat of paint.

Green growth is not just a visual issue. Algae keep the surface damp, dirt feeds them, and walls that stay wet age faster. We clean facades on detached and terraced houses, older buildings and commercial properties.

Common reasons for facade cleaning are visible growth on the weather side, the sale or letting of a property, the end of nearby building work or a planned repaint. In the last case cleaning is not an extra but the first stage of the facade coating.

Facades rarely get dirty evenly. Growth and streaks appear where water lingers or runs down. Typical problem areas are:

Insulated facades are especially prone. Because the thin render on the insulation boards receives hardly any heat from inside the house, it cools sharply at night and collects condensation – ideal conditions for algae. Near the sea, lakes or trees, high humidity adds to the effect.

The key rule: pressure follows the material and its condition. Solid brick tolerates more than mineral render, and render on external wall insulation needs particular care. On sensitive surfaces we work with low pressure; stubborn deposits on window reveals, cornices and mouldings are removed by hand.

Before cleaning, windows, doors, lights, vents and nearby planting are covered. On unfamiliar or delicate surfaces we clean a test patch first to check the effect. Where the type of growth requires it, we also use a cleaning agent suited to the material.

On insulated walls only a thin layer of render covers the insulation, so we clean them exclusively at low pressure and pay close attention to window joints, the plinth and penetrations such as lights or sockets, where water could get behind the render. Small holes or hairline cracks should be closed properly afterwards so that the insulation stays dry.

Brick needs its own approach. White efflorescence consists of salts from the masonry, and we brush it off dry first, because a lot of water can dissolve the salts again and carry them back into the wall. Recurring efflorescence points to moisture in the masonry whose cause should be investigated.

Depending on the building's height we work from the ground, from scaffolding or from an aerial work platform. Cleaning is done in frost-free weather, and the wall then needs time to dry – essential if painting or sealing follows.

Cleaning is enough when the wall is sound and the paint still adheres firmly. A simple test: run the flat of your hand over the facade. If plenty of colour comes off on your hand, the paint is chalking – its binder has weathered and a new coat is due.

Repainting makes sense when the paint chalks, peels, has faded badly or the render shows cracks. Cleaning then becomes the preparation for the facade coating. If moisture is coming from inside, for example rising damp in the plinth, the cause must be fixed first by a damp-proofing specialist.

On absorbent brick or natural stone, sealing can be worthwhile after cleaning. It makes rain bead off while still letting water vapour escape, and it slows new growth. Depending on location, we recommend cleaning a facade every five to ten years.

Many houses in southern Sweden and Denmark have rendered or brick facades that face the same damp, windy climate as homes on the German coast. For these walls our method is the same: assessment, protection, matched pressure and careful hand work at the details.

Timber cladding, which is common in Scandinavia, is a different material with its own requirements. If your house has wooden facades, send us photos first and we will tell you honestly whether the job fits our services. For all facade jobs abroad we plan the work as a scheduled assignment, ideally combined with other work on the same house so that travel is used well.