Green streaks on the north side of the house, a grey wooden fence and garden furniture covered in dust and leaves. A pressure washer freshens all of that up quickly. But facades and wood are much more sensitive than concrete, so with them it matters more to know when to stop than how hard to push.
Facade
Take a close look at the facade before washing. If the render is cracking, flaking or sounds hollow when you tap it, do not wash it at high pressure, as the jet can take off whole pieces. A facade like that needs repairing first.
- Rendered facade in good condition: Vario Power lance, low pressure, greater distance and a flat jet at an angle
- Facade with external insulation (thin top coat over polystyrene or mineral wool): only the lowest pressure and a large distance, or better a soft brush and garden hose, as the top coat is easily damaged
- Stone and brick cladding: medium pressure, with care at the joints
- Wooden cladding: low pressure, along the grain
Wash from top to bottom and do not aim the jet upwards under flashings, window sills or into joints, so water does not get into the wall. Go around windows, shutters and seals or wash them from a large distance. If the green marks come from constant damp in the wall, they will come back, so see our guide on mould and damp too.
Important: old corrugated roofs and cladding made of fibre cement sheets may contain asbestos. Never pressure wash such surfaces, as dangerous fibres are released.
Fence
| Fence | How to wash | After washing |
|---|---|---|
| Wooden | Low pressure, Vario Power, along the grain, at least 30 cm away | Let it dry for a few days, then protect with oil or wood stain |
| Metal and wrought iron | Medium pressure, careful with flaking paint | Clean rusty spots and protect them with paint |
| Concrete and stone | Medium to higher pressure, rotary nozzle for stubborn deposits | Sealing if you wish |
| PVC and plastic | Low to medium pressure, Vario Power | Nothing special needed |
Do not use the rotary nozzle on a wooden fence: the fibres get torn up, the wood becomes rough and soaks up moisture faster.
Garden furniture
- Plastic: medium pressure, and for greasy marks a product made for pressure washers
- Metal and aluminium: medium pressure, watch out for flaking paint and joints
- Hardwood (teak and similar): low pressure and a large distance, garden furniture oil once dry
- Synthetic rattan: low pressure and a large distance, as a strong jet can loosen or damage the weave
- Cushions and fabrics: do not pressure wash them, wash the covers according to the label and clean the filling with an extraction machine
Wash the furniture on the lawn or on the patio you are washing anyway, and leave it in the sun afterwards so it dries quickly.
Frequently asked questions
Can I pressure wash a facade?
If the facade is sound and has no cracks, yes, at low pressure and from further away. A damaged or crumbling facade, or one with a thin insulation render, is better washed with a soft brush and garden hose.
How do I remove green algae from a facade?
A low-pressure jet removes it from the surface, and for a longer-lasting result use an algae remover made for facades, following the manufacturer's instructions. If the algae keep coming back, the cause is damp in the wall or shade, and that needs to be dealt with too.
Can I clean the roof with a pressure washer?
We do not recommend it. Working on a roof with a pressure washer is dangerous because of the slippery surface and the kickback of the jet, water can get under the tiles, and old fibre cement roofs may contain asbestos. Leave the roof to professionals.
Can I use a pressure washer standing on a ladder?
Better not. A high-pressure jet has a kickback that can throw you off balance. For higher parts of the facade, use an extension lance or ask professionals.
When is a wooden fence dry enough to paint?
Usually after two to three dry, warm days, and longer in the shade. The wood has to be dry both to the touch and inside, otherwise the coating does not adhere well and soon peels.
Do I need a garden furniture cleaner with a pressure washer?
For most furniture, water is enough. For greasy marks, bird droppings or stubborn dirt on plastic, a product made for pressure washers, added through the Plug 'n' Clean system, helps.
Can a pressure washer strip paint off a fence?
It can remove paint that is already flaking, which is useful before repainting. At lower pressure it will not damage sound paint, but at high pressure and close range it can, so test on a hidden part first.
How do I clean windows on the facade?
Glass and frames do not need high pressure, and the jet can damage seals and drive water into the wall. Wash windows by hand, as described in our guide How to clean windows without streaks.
When is the best time to wash a facade?
In spring or early autumn, in dry, warm weather without strong sun, so the facade dries evenly. Do not wash it when frost is forecast.
How long does it take to wash a fence or facade?
It depends on the area and how dirty it is. According to the manufacturer, the Kärcher K 7 cleans up to 60 m² per hour, but on facades and wood you work more slowly and at lower pressure, so allow more time.
For all the jobs around the house you can hire a Kärcher K 7 from us, with operating instructions and delivery by arrangement.
