Ask the Expert Question-and-Answer Archive

by Ron Joseph

April, 2009

Cast Iron Gutter

Q. Could you please advise if the zinc paint would be suitable to treat a cast iron gutter that holds quite a bit of rainwater?

A. Zinc-rich paints come in different types ... some contain a high percentage of zinc, others contain less. Those with a high zinc content are very well suited to corrosion prevention. However, you need to prepare the cast iron by abrasive blasting to a white metal finish so that the zinc particles in the paint will be in direct contact with the iron. If you apply the zinc-rich primer to less than clean steel, you won't get the benefit of corrosion protection offered by these primers.

If you do the job properly, zinc-rich paints can be excellent. Are you planning on repainting old gutters or new ones? If they are old, you will need to be specially careful with the surface preparation.

Regards,

Ron Joseph