Water Repellent Wall Coating .....

[Deleted User]

This was being doorstep sold, to me, by a cold caller yesterday - what opinions do other Forumites have on it ?


He pointed out areas on my rendered wall where I had problems beneath the surface (wasn't aware of what those 'smoother' patches were) and suggested that those had to be rectified and then this coating would be applied ontop thus making the wall perfectly protected, breathable, and self cleaning thereafter.


Was wondering what experience others had with it.

Grenage

You don't want such things on your walls; they'll trap moisture in as much as keep it out.

Doozergirl

Awful s£&@.

This is not what houses were designed for, trapping moisture in the walls (which is the truth and the exact opposite of the way they sell it) is not a good thing for a building and it won't solve any problems of hairline cracks or blown areas in the render.

Fire_Fox

Breathable meaning porous to air/ some gases/ all gases? But blocks out liquids (water) and solids (dirt/ grime) regardless of particle size?

I am imagining a living 'smart' barrier, Genetically Modified lichen perhaps. :eek:

FreeBear

Fire_Fox wrote: »

Breathable meaning porous to air/ some gases/ all gases? But blocks out liquids (water) and solids (dirt/ grime) regardless of particle size?

Yup, just like Gortex fabric - That stuff is kinda shower proof, but you still get wet when it rains hard. And once wet inside, you take ages to dry out again. The other thing with "breathable" fabrics is the salts & oils in sweat block the pores, reducing the breathabilty... So no different to these snake oil treatments for buildings.

OP - Smooth patches on render would either suggest different application methods or repairs. Just fix cracks as & when they appear, paint with an appropriate coating when needed (i.e. lime wash on lime renders, Sandtex or similar on cement). Blown sections of render (they will sound hollow if lightly tapped) are not generally an issue if there are no cracks.

Don't do business with cold callers - Send them on their way with a flea in the ear and do your research before getting a proper tradesman in.