Compared

Soft wash vs pressure washing

On a roof, soft washing. High-pressure washing can strip the protective granules off concrete tiles, crack older slate and force water under the tiles (HP Roofing). WestClean says high-pressure jet washing is not appropriate for roof tiles in Ireland.

What each method is, what it's for, and the questions to ask.

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€900 to €2,500soft wash roof cleaning with treatment, RoofQuote.ie's national range
€400 to €700a standard three-bed with moderate moss, HP Roofing, Dublin
No high pressureon tiles or slates: low pressure and a biocide (WestClean)
13.5% VATon cleaning a house, the reduced rate, if the company is registered (Revenue)

FreeNo obligationOne company rings you, not fiveNothing booked until you say yes

Side by side

The methods compared

Method	Used for, as RoofQuote.ie puts it	A m², RoofQuote.ie
Manual scraping	Heavy moss removal from tiles and slates	€10 to €20
Soft washing	Algae, staining and lighter organic growth	€12 to €28
Biocide treatment	Slowing moss and algae regrowth	€4 to €10 extra
Pressure washing	Usually risky on older roofs	not given

From RoofQuote.ie's national guide. Thick moss is usually scraped first, then the roof is soft washed and treated.

The damage

What high pressure does to a roof

Strips the granules off concrete tiles and shortens their life (HP Roofing).
Cracks older slates and edges.
Forces water under the tiles, the felt and the ridge capping (WestClean).
Blasts out bedded ridge mortar.

Dirtbgone's point is that the damage isn't obvious on the day: it shows months later as leaks or early wear.

Where pressure fits

Where a pressure washer still belongs

Driveways, patios and paths. Some roof companies use controlled low-pressure systems, which is a different thing from blasting a roof (RoofQuote.ie). If a company's only answer is "we'll pressure wash it", ask again.

Ask

Questions before you book

Do you use soft wash or high pressure on the roof? WestClean's own answer: soft wash only.
Is a biocide treatment included after the clean?
Will you check for cracked tiles or slipped slates first, and show me?
Are the gutters cleared after?

See it first

Your roof clean, on your own photo

Take a photo of the house from the road and see the roof without the moss and streaks before anyone quotes. Free, in under a minute.

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Preview of your photo, not a guarantee. Your photo goes to Google's Gemini service to make the picture and isn't kept.

A photo that works

Daylight, from the footpath or the garden.
The whole roof in the shot, ridge to gutter.
The worst side: usually the north-facing slope.
Never go up on the roof to take it.

FAQ

Questions people ask

Can I pressure wash my roof myself?

The companies here advise against it: it damages tiles and slates and forces water under them (HP Roofing). It's also work at height: the HSA calls roofwork a high-risk activity.

Is soft washing more expensive?

On RoofQuote.ie's rates a m², yes, €12 to €28, because the biocide is part of it. It also lasts longer than water alone.

Does a soft wash work on thick moss?

Thick cushions usually come off by hand first, then the roof is soft washed and treated.

Keep reading

Related guides

Where these numbers come from (2 public sources, checked 3 November 2026)

Sources (4)

Prices and facts on this page were checked against these published pages. We are not connected to these businesses.

HP Roofing: hproofing.ie
WestClean: westcleanpropertycare.ie
RoofQuote.ie: roofquote.ie
Dirtbgone: dirtbgone.ie