Saint Gobain Weber talks halo rings and how you can deal with them

Saint Gobain Weber defines halo rings or snakes as rings of discolouration on a rendered elevation which are caused when render is applied improperly.

Monocouche renders are designed as a one coat material to be applied in two passes. The passes must be applied at approximately equal thickness, or as a slightly thinner first pass, followed by a slightly thicker top pass. Halo rings occur when the second pass is applied as a thin coat over the first. Another factor which contributes to the occurrence of halo rings is using a wetter than necessary render mix.

When this is the case, during the scraping process, the laitance layer is exposed, and a lighter ring of material is produced. Further scraping will only cause the ring to get bigger.

Unfortunately, there’s not much that can be done to fix a halo ring once it’s appeared. However, one thing that can be done is another coat of render can be applied. The following steps should be followed in an effort to remedy the situation:

1. Brush the area down and remove any loose materials, clean with a mild detergent or biocide wash such as weber CL150 if necessary, and allow to dry
2. Re-set details using a 10mm profile bead, fixed with weberend aid or  weberend bead adhesive
3. Apply weberend aid at 2-3mm and stipple using a brush or loaded roller and allow this to cure for at least 48 hours
4. Apply a 10-12mm pass of a render such as weberpral M and finish as required

Always follow the instructions printed on the bag of the particular Weber product you are using. If you need additional information, please review the technical datasheet which can be found on our product pages, or contact our Technical Department.