The standard garden shed erected 6 years ago and treated with an unknown preservative, has developed a band of heavy mildew 12" approx from the base - on the Norh facing side in particular, but also at the front and back. I cleaned the path around it with a HP jet wash very effectively, but daren't use it on the shiplap boards for fear of flooding the shed.
What other budget price treatment might I use prior to applying fresh protective treatment please? :)