Lisa Breakspear explains why a thorough spring clean is essential for restoring and protecting external paving after winter
A SPRING deep clean of external paving is essential for performance and tile aesthetics. Over the winter months, organic contamination quickly builds up. Blackspot and algae are particularly common in our damp climate, especially on north-facing elevations and in shady areas, along with mud, leaf tannins and rust marks. If left untreated, these can become more difficult to remove and may impact the overall finish.
To tackle organic build-up, along with tree sap and any oil and grease residue, you’ll need to use a quality alkaline cleaner. Choose a biodegradable solution and avoid using anything that contains Sodium Hypochlorite; it isn’t safe to use where plants and metals are present and won’t be effective at breaking down grease and oil.
It can also cause ‘yellowing’ when used on light coloured surfaces. Most quality alkaline solutions can be diluted depending on the level of contamination and they’re safe to use on natural stone, concrete and porcelain installations.
On paved areas with grouting, a good alkaline cleaner will also remove any contamination from the joint and we recommend using a long-handled brush and a hose pipe. This method will be effective for even the heaviest levels of contamination, without the need to use a pressure washer which can often weaken or blow out the grout joints.
After wetting the surface, apply the diluted solution and work it over the pavers; it’s important to allow sufficient contact time during which the contamination will start to break down; a longer contact time may be required if the contamination is really heavy.
For stone, terracotta and porous surfaces, look to reapply a sealer/impregnator once all stains and contamination have been removed.
A water-based product will provide environmental benefits and will also allow for application in damp conditions and over residual moisture, speeding up the process.
Going forward, it’s worth putting a regular maintenance regime in place, to avoid contamination building up. A good quality pH-neutral solution will be safe to use on all surfaces – outside and indoors – and, like the alkaline cleaner, can be diluted according to the degree of contamination.
Ongoing spot cleaning, to remove rust, grease and organic residue will also keep surfaces looking and performing at their best.
