What we do
That rusty pink stain creeping across your south-facing wall is red algae - known properly as Trentepohlia. Unlike green algae, which favours damp, shaded corners, red algae loves sunshine, which is why it appears so often on sunny gable walls and roof edges across Ireland. It looks like a light dusting of brick dust at first, but left alone it spreads, stains render and paint, and holds moisture against the surface. We remove red algae with a targeted biocide wash followed by a careful low-pressure rinse, killing the growth at the root rather than just scrubbing the stain. We treat rendered walls, patios, driveways, garden paths and roofs across all ten counties we cover, and we leave every surface clean, even and protected against regrowth for as long as possible.
Rendered wall treatment
We remove red algae from south-facing rendered walls and gables, restoring the original colour of the render.
Patio & driveway cleaning
We clear red algae and staining from concrete, block paving, porcelain and natural stone patios and driveways.
Garden path & step cleaning
We treat paths, steps and garden walls so the pink staining lifts and the surfaces look freshly laid.
Regrowth prevention
We apply a biocide treatment as standard so red algae takes far longer to reappear in our damp climate.
Pricing note: Priced by the surface area and how established the growth is. Most walls, patios or driveways cost between €150 and €450, with a fixed quote agreed before work starts.
How it works
- 01
Survey & Quote
We inspect the affected surfaces and give you a fixed written quote before any work begins.
- 02
Biocide Treatment
We apply a targeted biocide wash that kills the algae at the root without damaging render or paint.
- 03
Low-Pressure Rinse
We rinse the treated surface carefully, lifting the dead growth without etching or damaging the material.
- 04
Final Check & Clean-Up
We inspect the finished surface, protect against early regrowth and leave the site spotless.
Frequently asked
- How much does red algae removal cost?
- Most house walls, patios or driveways cost between €150 and €450 depending on the area and how established the growth is. We inspect first and give you a fixed quote with no hidden extras.
- What is red algae and why is it on my wall?
- Red algae (Trentepohlia) is a type of algae that thrives in sunshine and moisture, which is why it appears on south-facing walls in Ireland. It shows up as a pinkish-red or rusty orange dusting that spreads over time.
- Will you damage my render or paintwork?
- No - we use a biocide wash and low-pressure rinse rather than blasting the surface. This lifts the growth without etching render, loosening paint or scouring stone.
- How is red algae different from green algae?
- Green algae grows in damp, shaded areas and appears as green patches. Red algae prefers sunny walls and looks like a rusty pink stain. Both are treated with a biocide wash, but red algae needs the root treatment to stop it coming back.
- Will the red algae come back?
- Any algae will eventually return in Ireland's climate, but the biocide treatment we use as standard knocks the growth back at the root, so it takes far longer to reappear than with a simple pressure wash.
- Do you treat patios, driveways and roofs too?
- Yes - we remove red algae from rendered walls, patios, driveways, garden paths and roofs across Galway, Mayo, Sligo, Leitrim, Roscommon, Longford, Westmeath, Cavan, Monaghan and Donegal.
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