Tiger Striping and what You can Do About It

Have you noticed discoloured stripes on the outside of your gutters? If the answer is “Yes,” the good news is that they won’t do any immediate harm to the gutter system. Since most gutters are neutral or lighter shades, tiger striping is more noticeable on houses with dark-shingled roofs and medium to dark coloured siding. Most homeowners want to deal with the problem right away because of how it detracts from a home’s curb appeal. If your gutters suffer from vertical streaking, here are some things you should know about tiger striping and what you can do about it.

How Tiger Stripes Form on Gutters

A popular myth attributes striping to the deterioration or breakdown of the finish (paint, sealant, or another type of coating) itself. But tiger stripes on gutters are actually caused when particles of dirt, grime, and pollutants such as insecticides, tree sap, pollen, and fumes get trapped by the moisture collecting at the lip of the gutter. When droplets become large enough to roll downward, they bond with the metal surface, creating the unsightly vertical streaks known as tiger stripes or tiger striping.

Can’t Just be Rinsed Away

It is because of this oxidation process that just rinsing the outside of the gutters or even power washing doesn’t work. Depending on where you live, both climate (annual rainfall, humidity, environmental pollutants, etc.) and micro-climate (lots of trees, live near a factory, house next to a busy road), striping can appear light brown (minimal oxidation) to black (maximum oxidation). The gutter system will need to be cleaned with a non-abrasive gutter cleaner and a soft cloth or soft-bristle brush, before the gutter sections can be rinsed with clear water. If the tiger striping is very pronounced, more than one application of the cleaning solution might have to be applied.

Presence of Mold

The darker the tiger stripes might make it harder to detect the presence of mold or mildew. To remove the tiger stripes and eradicate the mold, you will have to use a heavy duty cleaner formulated to remove both deep-seated stains and organisms.

How to Prevent Tiger Striping

While there is little immediate danger to the gutters when tiger striping first appears, over time the process can permanently damage the finish, compromising how well the gutter system protects your home. Ways to prevent tiger stripes from occurring include:

  • Cleaning the gutters twice a year
  • Getting into the habit of washing the outside of the gutters at the same time to reduce the build-up of pollutants
  • Installing gutter guards or some type of leaf protector especially when a lot of trees grow around the house