Is Roof Cleaning Worth It? Why Low Pressure Matters

A dark, streaky roof is one of the fastest ways to make a house look older than it is. But is roof cleaning really worth paying for, and can it do more harm than good?

What grows on your roof

• Black streaks are usually algae. They look bad but are mostly cosmetic.
• Moss grows in thick green cushions, mainly on shaded, south-facing slopes. It holds moisture and can lift tiles.
• Lichen forms crusty grey, yellow or orange patches that root into the tile surface.

Why it's worth it

Kerb appeal and resale value

The roof is a large part of what you see when you look at a house. A clean roof makes a huge difference to first impressions, which matters most when you're selling.

Protecting the tiles

Moss and lichen hold water against the tiles. Over time that speeds up weathering of the surface and can let water work into the overlaps.

Spotting problems early

A clean roof makes cracked tiles, loose ridge capping and damaged flashings easy to spot before the summer storms find them for you.

Preparing for painting or sealing

Roof paint and sealers need a clean, sound surface to bond to.

Why low pressure matters

Blasting a roof at full pressure is the most common roof-cleaning mistake. It can:

• strip the surface coating from concrete tiles,
• crack older, brittle clay tiles,
• force water up under the overlaps and into the ceiling.

Professional roof cleaning uses low pressure combined with suitable cleaning solutions. The solution does the hard work of loosening growth, and gentle rinsing carries it away without damaging the tiles.

The verdict

Done properly, roof cleaning is absolutely worth it: for appearance, for maintenance and for peace of mind. Done badly, it can cost you more than it saves. Choose someone who explains their method.

Find out how we do it on our roof cleaning page, or ask for a free quote.