Have you noticed red streaks on render? Usually, the red streak is a type of algae called trentepohlia. While considered green algae, trentepohlia produces an orange/red pigment that impregnates and stains the rendered surface. They are usually in streaks simply due to gravity forcing the trentepohlia vertically down the wall.
Red streaks on Render – Why do they appear?
Modern renders look great on properties and walls. You can choose your colour, and the render won’t fade or need painting. However, they have been sold as maintenance-free, but in our mild and wet climate, this is only sometimes true.
Modern render is soft and porous. Most houses have such good insulation trapping heat inside that there’s often no heat loss to help dry walls out. Shaded rendered walls can stay wet after rainfall for some considerable time. Prevailing winds carry algae spores which find a home in the damp and porous render. Once on your wall, they will continue to grow and spread until treated.
Usually, green algae will appear first, followed by red streaks on your walls from trentepohlia. Trentepohlia (the red staining) is very adaptable and hardy. It will proliferate on any surface where it can gain a foothold. Render, brickwork, pebbledash and natural stone are especially susceptible due to their porous and rough texture. Our damp and mild UK climate is perfect for trentepohlia to thrive.
Can red streaks be removed from my render?
The short answer is yes, but it takes much work. A high-powered pressure washer will damage the soft render. Incorrect or badly mixed chemicals can cause unintended damage to your render, window frames, doors, surrounding plants, and wildlife. Red streaks are the most difficult to clean. This is because the red pigment penetrates the render and stains it like a dye.
At Exterior Cleaning Pros, we have cleaned well over 700 rendered properties and walls. We have the experience and knowledge and invested in the correct equipment. We use the most appropriate chemicals to remove these red stains on your render and return it to its best state.
Why not overpaint the render?
The render is coloured throughout the mix applied to the wall. It won’t fade or need recolouring at any stage of its life cycle. From time to time, it will need to be cleaned to remove contaminants and return the render to look its best.
If you paint the render, you will create an expensive job that needs to be redone every 5-6 years. You will need to clean your render as part of the painting preparation process, the paint will not stick to algae, mold, or lichen and will begin flaking off over time.
We can clean your render for a fraction of the price of painting it and your render will look its very best, just as the manufacturer designed it. Call or email us today to discuss how we can remove the red staining and any other contaminants from your render. We can revive your render to its former glory.
