I am looking at painting a metal sheet fence with a spray gun.

How do I calculate the amount of paint needed?

What are the preparations that I need before painting, should I use a primer, do I need to wash it first with a pressure hose? Sand it?

The fence is a Galvanized steel fence, and it has been painted before. I will be spraying outdoors, and there is small gaps between the sheets. they are +- 2 meter wide sheets side by side.

The spray gun I am using: High Volume Low Pressure (HVLP) system with 1.4-1.7mm Fluid Tip.

  • This is quite a difficult question, there are some factors which will need to be determined before you will get a good answer: What "metal" is the fence, and has it been treated/painted before?, also, will you be spraying indoors or outdoors and are there many gaps between the metal or is it just large sheets?
    – Hightower
    Nov 12, 2013 at 14:11
  • I would imagine the type of spray gun also plays into how much paint is required--some types are known for low overspray.
    – mac
    Nov 12, 2013 at 16:12
  • Check my update
    – Luis
    Nov 12, 2013 at 23:03

1 Answer 1


You'll have some waste with spraying. Considerably more than with a brush or roller, anyhow. Find the square footage---both sides---and divide 325 into it. You'll get about that amount, 325 square feet per gallon, if you're careful. You will likely need more than one coat…

Also, make sure the surface has been well prepared by removing loose paint and sanding rust spots. You'll want a good primer, preferably oil-based, on those bare spots.

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