Decking was all the rage in the early noughties, as sales went through the roof on the back of the success of Ground Force.
One question we often get asked at Amateur Gardening is how to revive sorry-looking decking without the use of algae-killing chemicals – or taking up and replacing decking boards.
First, brush decking boards down and remove any leaves, mud and debris. Pressure washers throw up a lot of muck, so move any garden furniture or pot plants out of harm’s way.
Choose (or hire) the biggest and most powerful pressure washer you can afford. Entry level models which cost around £100 are fine for washing cars or blasting garden furniture, but they’ll sometimes struggle to provide enough power to give decking a proper clean.
If you’re on a water meter, opt for a washer that connects to a water butt. It’ll drain the butt reasonably quickly, but it’s the most environmentally-friendly way of cleaning a timber deck.
For wooden decking, use a standard (flat) pressure washer attachment and move it slowly over the surface of the wood. Don’t hold it closer to the wood than a few inches, or hover it over the same spot, or it risks eating into the wood.
Avoid going over the same area several times, or the wood will appear lighter than other sections of the deck. As our pictures (above and below) show, the difference between untreated and pressure-washed wood is already clearly visible.
For paving, switch to a rotating nozzle (below). These fittings are incredibly effective at blasting muck from slabs, although it’s worth wearing eye protection as bits of mortar can accidentally be blasted out from inbetween pavers.
Never use a rotating nozzle on timber decking, fence panels or sheds though, as it’ll gauge lines into the timber and ruin it.
We used a Karcher K7 for this trial (pictured near the top of this article), which effortlessly shifted algae and grime from decking and paving. It’s one that can draw water from rain-filled butts – if you want to avoid adding too many zeros to your metered water bill.