22/02/2025
Do hydrophobic wall coatings really work?💦
It may come as a surprise to learn that the outer skin of a cavity wall is not designed to be completely waterproof. If the cavity is kept clear and the mortar pointing is in good condition the small amount of ingress and condensation should run down the inner face, of the outer leaf, and be channeled back out by appropriate cavity trays where the cavity is interrupted (extensions/windows/doors) or run to ground and soak away where it is not.💧
Where there is a lack of cavity trays above a lintel this phenomenon can lead to damp around windows and doors.🪟
In the case of retrofit cavity wall insulation having been fitted, this can cause a bridge between the outer and inner masonry leaves, and lead to penetrating damp and ultimately mould growth.🦠
Even the porosity of the brick or stone can play a huge part in this; sandstone is incredibly porous as indeed are most modern facing bricks 🧱
As for the original question; we have successfully treated:
A lack of appropriate cavity trays/ingress hitting steels or lintels ✅
Bridging effects caused by cavity wall insulation/cavity blockage ✅
Ingress through sandstone ✅
So in summary, not only does it work, being BBA certified and Energy Saving Trust approved, it can save you money on energy bills. 💵
Water conducts heat 20-25 times faster than air , so it can be said that a wet wall is a cold wall.🥶
If you believe you are having problems with water ingress through external building fabric: walls, roof, gutter, pointing, windows or doors, please feel free to book a free assessment and quotation.
