After a few or several years, a facade may need to be refreshed or wholly replaced. Old elements not only spoil the aesthetics of the building, but can negatively affect the external wall insulation. When is it necessary to replace the external renders? And when only renewal is enough?
Replacing an external render – why might an old render need to be replaced?
Among the most common reasons a mineral or cement renders may need to be replaced are:
Falling off rendering
Often the first indication that a facade needs to be replaced is falling off render. In that case, we must scrape off the old layer of plaster, clean the substrate, prime, and repaint the facade. However, before proceeding, it is necessary to assess the condition of the entire wall. If cracks have appeared on its surface, it may mean that the wall’s stability has been compromised.
The facade also needs to be replaced if it develops dampness. This can be related to damaged flashing, leaking gutters, or down pipes. Sometimes it is enough to remove the defect and dry and renovate the exterior walls.
Algae and mold
Algae and mold can also appear on the facade. Thin-coat renders without lime are primarily at risk of this phenomenon. They usually appear low to the ground, on the north wall, and in areas of leakage from under cornices and flashings. In this case, it is worth considering to put a plaster onto clean wall with increased resistance to greening.
Replacement of the render
There are many different types of render available on the market. The most popular are rendering systems, after the application of which the external wall gains an aesthetic appearance and is properly protected from bad weather conditions. When deciding on this type of facade, it is necessary to choose the right type of render.
- Silicone render is characterized by high resistance to dirt, moisture, and high temperatures in summer. Properly made, it can serve for years without worrying about changing color under the influence of, among other things, sunlight. However, silicone renders are not very resistant to very low temperatures and mechanical damage.
- Acrylic render, on the other hand, is resistant to low temperatures and mechanical damage. We can safely use modern acrylic renders on shaded walls due to its low resistance to sunlight. Its disadvantage is the difficulty of keeping it clean.
- Mineral render are the renders most resistant to sunlight and adverse temperatures. Its undoubted advantage is the excellent ease of maintenance. However, this solution has its drawbacks – low resistance to prolonged, intense rainfall and the effects of water vapour.
Renovation of the render – when can you avoid replacing the modern renders?
A dirty exterior wall with acrylic or cement render that has lost its luster can sometimes be renovated with little money. In addition, we can do some work by ourselves without engaging a renovation team. In this way, we may avoid labor costs.
– If an external rendering is undamaged and does not fall off the wall, and only the facade paint has lost its color, it is enough to repaint the substrate.
– If a house rendering is scratched or damaged, and these are minor scratches, it is sufficient only to paint external walls with silicone or acrylic paint.
– If an external rendering is peeling away from the substrate, we should scrape the wall, clean the cavity of dust, and prime. Then it is essential to fill the cavities with new render and, if necessary, cover them with paint.