Green walls!

[simondyntDBeK]

Just bought a lovely cottage with a nice barn attached. Some of the interior walls are a bit 'green'!

Can I just power wash this off? Anything to be aware of?

Cheers.

 

[jbonevia]

Get some BAC50 Benzalkonium Chloride, works really well to kill moss and algae and inhibit regrowth.

 

[JohnD]

A commercial product called "wet and forget" can be used. They sell it mail-order. There is usually a Special Offer on.

power washing is likely to dislodge old mortar and smaller stones.

 

[StephenOak]

@JohnD tells people to use Wet & Forget which may be, but often isn't, good advice. Wet & Forget & Patio Magic are commercial products which have Benzalkonium Chloride as the active ingredient at c. 5-10% level and you dilute them down to the 1-2% level.

If you are absolutely sure that you will only ever need to use the stuff once then Wet & Forget or Patio Magic will do. If not then follow the advice from @jbonevia and get some BAC50, Benzalkonium Chloride at 50%. That will keep you going for many years.