Signs Your External Wall Insulation May Need Attention

24.06.2026

Most external wall insulation systems do not need much maintenance, but it is still sensible to keep an eye on them.

A quick visual check once or twice a year can help spot small issues before they become expensive repairs.

Look out for:

  • Cracks in the render.
  • Staining or discolouration.
  • Green or black algae growth.
  • Loose or hollow-sounding areas.
  • Damage from impact.
  • Water marks below gutters or windows.
  • Render pulling away from edges.
  • Poor drainage around the base of the wall.

Small hairline cracks may not always be serious, but larger cracks or cracks that continue to grow should be checked by a professional.

The same applies to hollow areas. If part of the system sounds hollow when tapped, it may suggest that the insulation has started to come away from the wall. That should be looked at quickly before water gets behind it.

The earlier a problem is dealt with, the easier it usually is to repair.

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