Cleaning your house exterior: get the outside of your home sparkling again

Nothing is as exposed to external influences as the exterior of your house. Rain, dust and dirt settle on the surface, and UV rays, heat and frost also have an impact. Over time, visible traces form that not only affect the beauty, but also the condition of your home. Thorough cleaning and care counteract this and can be performed effortlessly using simple household cleaning agents and a pressure washer.

Cleaning your home’s exterior walls: different types of exterior surface

Before getting the pressure washer out of the garage, you should carefully inspect the facade. First, the type of surface is important, as each material requires a different cleaning approach. The condition of the exterior wall must also be considered. Old and damaged facades should only be cleaned after consultation with specialists.

Hard-fired clinker can be cleaned quickly and effectively using a pressure washer. However, make sure that the facade is made from hard-fired clinker and not another type of brick. While the former can withstand water pressure up to 200 bar, softer bricks can break under high pressure.

Particular care should also be taken if there are any loose bricks or damaged joints.

Do not use the brush in a circular motion when cleaning a clinker facade, as this can damage the protective layer on the bricks.

Stable lime and cement render facades are perfectly happy to be cleaned with pressurised water, though it is important not to work on a single spot for too long, as the water impact could cause paint and other material to be removed. A fan jet nozzle helps to protect against this.

Composite resin however, is sensitive to pressure washing. For this reason, you should start by testing it out – with low pressure and sufficient distance – on an unobtrusive area, to see whether pressure washing will damage the facade. Gentle cleaning is particularly recommended if there is a thermal insulation composite system (TICS) or external wall insulation (EWI) under the exterior render. Clean composite-resin-rendered and insulated exteriors using a soft brush and a mild cleaning agent.

Over time, render and paint can start to crumble, chalk or flake off. To avoid damage during house washing and cleaning, check the facade for stability and cracks by wiping. Knocking can help you detect any cavities. If you discover any damaged areas in a rendered facade, do not start cleaning it: instead you'll need to think about giving it a new coat or arranging for it to be renovated. 

Good results can be achieved with a pressure washer, depending on the type of wood. Before cleaning a wooden exterior, make sure the cladding is completely sealed and the insulation behind it remains undamaged by water and pressure. As a precaution, clean open wooden cladding by hand.

Do not use the rotary nozzle as the hard water jet from this can damage the surface of the wood. Hold the nozzle of the power tool at a good distance (around 25 cm) and start with low working pressure, which you can increase if necessary:

• Hardwoods from deciduous trees such as robinia and oak can withstand a maximum water pressure of 110 bar.
• Softwoods from conifers such as spruce and larch can withstand water pressure of around 50 bar.

Work until the whole facade is a uniform colour and then leave the wood to dry. The result will be that your wooden facade shines in its original colour. During cleaning, the top layer of wood is removed, leaving a rough and delicate surface. It is particularly susceptible to moisture and dirt in this condition so it should be properly sealed.

General tips for cleaning the outside of your house

• A pressure washer must not be used in rain or humid environments.
• For safe working at height, you should use a secure work platform. You can also get hose and lance extensions for extra reach. 
• Close windows and doors.
• Mask light switches and sockets.
• Clear away plants and decorations.
• Test the cleaning agent and water pressure in an unobtrusive spot.
• The best time to clean the outside of your house is on a spring or autumn day, when it is sunny but not too hot, as this speeds up the drying process. It’s also handy to clean after a rain shower, as this means the walls are already wet and so the softened dirt comes off more easily.

If necessary, you can increase the water’s cleaning power by adding a cleaning agent. Check in advance whether your home’s exterior is acid-sensitive. Only neutral or alkaline cleaning agents should be used on natural stone and rendered facades. To protect the environment, use biodegradable cleaning agents such as the STIHL CS 100 stone and facade cleaner. This cleaner reliably removes tough green deposits, accumulated exhaust emissions, grime and dust.

Cleaning the outside of your home using a pressure washer

Step 1: pre-treat

Use the pressure washer to moisten the exterior of your house and remove coarse dirt from the wall. For surfaces that are not delicate, use the STIHL RA 110 surface cleaner. The attachment cleans horizontal and vertical surfaces quickly and without splashing. The water pressure on the surface cleaner can be set directly and adjusted to the sensitivity of the surface to be cleaned.

Step 2: soak

Apply the cleaning agent over a large area with the high-pressure cleaner and give it a few minutes to take effect; don’t let the surface dry out completely during this time.

Step 3: scrub

If necessary, scrub the wall with a wash brush attachment.

Step 4: rinse

Rinse the dirt and foam from the facade using the surface cleaner. Work from top to bottom – this prevents dirt from getting onto surfaces that have already been cleaned.

Cleaning the outside of your home: household cleaning products

Hot water, a scrubbing brush and soft soap or washing-up liquid are all you need for tackling small surfaces and light soiling. STIHL stone and facade cleaner can also be distributed manually using a sprayer.

Cleaning exterior walls without a pressure washer

Step 1: dampen surface

Spray the facade with a garden hose to moisten it.

Step 2: apply cleaning agent

Distribute the cleaning agent evenly across the house wall. This is easier if you use a sprayer.

Step 3: clean your home’s facade

Brush and scrub the surface from top to bottom, then rinse dirt away with clean water.

Cleaning organic dirt from exterior walls

Climbing plants, algae and bird droppings are a nuisance and can permanently damage the exterior of your home. To permanently clean organic dirt from exterior walls, you’ll need the appropriate technology and suitable cleaning agents.

Summary: cleaning Your House exterior

• Regular and thorough cleaning of your house exterior keeps it in good condition and looking great.
• Some facade types can be cleaned with a pressure washer and others should be cleaned by hand.
• Intact clinker brick, render and wood facades can withstand water pressure. A gentle manual approach is recommended for delicate composite resin and TICS. Damaged and old facades should only be cleaned after consultation with specialists.
• Hot water, a scrubbing brush and soft soap or washing-up liquid are all you need for tackling small surfaces and light soiling.
• To reduce environmental impact, use biodegradable cleaning agents. The STIHL CS 100 Stone and facade Cleaner is environmentally friendly and can be used with a pressure washer or for washing by hand.
• Organic dirt, such as climbing plants and algae, can damage exterior facades. 
• To permanently remove ivy, you should first detach or cut off all branches and anchoring roots from the facade. Then dig up the roots from the soil and leave them to dry out.
• Algae is prone to develop on moist surfaces, and TICS facades are particularly susceptible. Use facade cleaner or soda crystals to remove algae coatings. Always wear safety glasses when using soda crystals, as they are an irritant.
• Bird droppings can be quickly removed with a pressure washer or just water and soft soap.