If this doesn t work you can sand the pergola and apply a fresh layer of stain and sealant.
How to clean pergola roof.
You want to keep the bleach concentration low to avoid staining or damaging the wood.
To remove stains and mildew mix a cup of vinegar oxygen bleach with a gallon of plain water and apply it on the stains soon after hosing down your pergola.
How to clean an aluminium pergola.
In a bucket combine some cold or warm water with some liquid dishwashing soap the kind you use for washing.
But your hard work will pay off.
If it needs cleaning you can use a low pressure power washer to clean away any debris or mud.
Here is a link for the thompson s water seal i used.
Rinse immediately after each section.
Most manufacturers and installers seem to recommend to clean your polycarb roofing pretty regularly with warm soapy water and a soft brush.
This works best if the hose is on a.
Regular clean ups will ensure that these stains are tackled and your pergola looks elegant all through the year.
Take a garden hose and give the entire aluminium pergola a good hosing down from top to bottom.
Gently wash your pergola with soap and hot water in sections.
Leave it on for a few minutes and use a brush to gently rub the stains off.