Cleaning outside painted walls

[emuchops]

My house has painted smooth rendering outside which is covered in green algae. How do i get rid of this? Will a pressure washer work, or should I get a long handled paint brush and paint something on it? It goes as high as aboout 20 feet. I dont like heights and I have no close water tap to hook up a pressure washer to....

[woodchopper]

A pressure washer would be best to remove the algae - you can get fittings nowadays to connect a hosepipe to even a kitchen tap.
Blast it with a power washer then soak it in a solution of a product called Armillatox ( available from garden centres ) that will kill off chemically any remaining algae and once dry repaint. Best to get a paint that is resisatant to algae.
As for the height - best to get some scaffolding hired out for a day or two.

[malpal]

I'm very wary of pressure/jet washers ever since it blew a hole in the tarmac on our drive. I use Jeyes fluid. Us as per instructions on the tin. Don't buy it ready mixed - it's miles more expensive than mixing it youself. You can use a yard brush to scrub it.

[woodchopper]

I would never use a power wash on tarmac.
Have both used Jeyes and Armillatox - by far Armillatox is better.