If your house was just washed and the gutters still wear evenly spaced black vertical streaks, nothing went wrong — tiger striping simply is not dirt. It is oxidation bonded to the aluminium, and removing it is the ‘brightening’ half of gutter cleaning and brightening.
What the stripes are made of
Rainwater sheeting over the gutter lip carries shingle residue, atmospheric pollution and organic particles. Where it runs down the face, it reacts with the aluminium’s oxidising surface and the factory paint, forming an electrostatically bonded stain in the drip pattern — hence the tiger stripes.
Because the bond is chemical, detergents and soft-wash solutions clean around the striping and leave it intact. That is why freshly washed houses so often still look tired at the roofline.
What brightening involves
A dedicated gutter brightener — typically a butyl-based or similar cleaner formulated for oxidation — is applied to the face, agitated, and rinsed before it can dry. It is real labour, linear foot by linear foot, which is why it is quoted as its own line rather than absorbed into a house wash.
The result is usually striking: gutters go from streaked grey to something close to their original white, and the whole roofline reads a decade newer.
The limits worth knowing
Brightening removes oxidation staining; it does not repaint. Where the factory finish itself has failed — peeling, chalking through to bare metal — the brightener reveals clean but worn paint. On old, heavily weathered gutters the honest outcome is ‘much better’, not ‘new’.
We will tell you which category yours are in before we start, because the difference matters to whether the spend is worth it.
If the stripes are what bothers you, say so when you book — it is a separate step and we will quote it properly. Read more about gutter cleaning and brightening →