By the Sleak Property Services team ·
A jet wash is the first thing most people reach for when a drive or wall goes green. On modern block paving and concrete it's the right tool. On a period house in Lytham or St Annes, with soft old brick, lime mortar, sandstone steps or painted render, it can do real damage.
Short answer: pressure wash hard, modern surfaces like block paving, concrete and patio slabs. Soft wash anything older, softer or painted: render, old brick, stone, roof tiles, fascias and timber.
What pressure washing is
Pressure washing uses a high-pressure jet of water to blast dirt, moss and algae off a surface. It's fast and gives an instant result on hard surfaces. The problem is that the same force that lifts moss off a patio can also lift the surface of the material itself.
What soft washing is
Soft washing uses low water pressure, closer to a garden hose, with a cleaning solution that kills algae, lichen and mould at the root. The solution is left to work and then rinsed off gently. Because it kills the growth rather than just knocking the top off, surfaces usually stay clean for much longer.
Which suits which surface
- Block paving, concrete drives, modern patio slabs: pressure washing, followed by re-sanding block paving joints
- Render (painted or through-coloured): soft washing
- Old or soft brick and lime mortar: soft washing, or a very low pressure rinse
- Sandstone and natural stone steps and paths: soft washing
- Roof tiles, fascias, soffits and gutters: soft washing
- Timber decking and fences: low pressure with care, as a jet will raise and splinter the grain
Why older homes in Lytham St Annes need care
Many houses in central Lytham, around the Green and in older parts of St Annes were built with soft bricks and lime mortar. A high-pressure jet can strip the hard outer face off old bricks and wash mortar out of the joints, which lets water in and leaves the wall worse than before it was cleaned.
Parts of both towns are conservation areas, where the look of the front of a building is protected. Cleaning doesn't normally need permission, but damaging original brick, stone or render and then replacing it with something different might cause problems. Gentle cleaning avoids the issue completely.
Keeping it clean afterwards
Green growth comes back fastest on north-facing walls, under trees and wherever water runs down a surface. Clear gutters, a trimmed-back hedge and a soft wash every couple of years will keep most fronts looking clean. Block paving stays cleaner for longer if the joints are re-sanded after washing.
Common questions
Can you pressure wash render?
It isn't recommended. High pressure can crack or strip render and drive water behind it. Soft washing cleans render safely and kills the algae so it stays clean for longer.
Is soft washing safe for plants and pets?
Plants near the wall are wetted down and covered before cleaning, and the surface is rinsed afterwards. Pets should be kept inside until the area has been rinsed and is dry.
How long does a soft wash last?
Usually much longer than a jet wash, because it kills the growth at the root. Most walls stay clean for a few years, depending on shade, trees and how wet the wall gets.