We have a house that was sided, I'm guessing, sometimes in the sixties, early 70's. It is steel, has chaulked off and looks like it needs a bath or a painting. How do you wash steel siding? Can it be repainted and how big a job is that? Thanks, Helen

Steel and aluminium siding may have self cleaning paint which is designed to chaulk off the outer most surface over time. Your can wash it with a soft bristle brush and TSP, wear cloves and goggles. If you want to paint you still have to wash the siding first so try that and lets see what it looks like.

Thanks for the answer. We will try cleaning it first. I did try a small patch and the metal underneath shows through. Maybe I'm past washing?? HElen

Helen when we bought our house it was past washing to make it look good. We even had to remove a plant that was growing up the side that was suctioned to the siding... we had to sand some of the plant off to smooth out the surface.
We used a product called dirtex cleaner to wash it and then followed up with a rinse.

My advice is to use a satin paint on the metal... we used flat and while it looks great our house it's a light yellow and it does not clean off as well as the trim which we painted in satin. If I had it to do over I would paint the body of the house in satin and paint the trim in either semi gloss or enamel.

Also to help decide on a color, I printed off a black and white copy of our house and bought a large set of colored penicls and colored my house in the colors that I was interested in. That way you can get an idea of what it will look like before you paint it.
I even added shutters and drew in lattice at the bottom of the porch, colored my mulch and added plants for the full effect...

I hope you enjoy the paint job as much as I did.

As a side note if you choose a really dark color they may have to order it. The store I bought from only sold the dark colors in 1 gallon containers so it ended up costing more.

Painting the siding is pretty easy with an airless sprayer, I did my house and the siding itself only took about 2 hours once I got all set up. The trim and everything else had to be brushed, but by spraying the siding first I didn't need to tape much off, just oversprayed and painted the trim color over that.

RE: washing steel siding to prep for primer and paint, I've seen.. use TSP or vinegar in water... is either better?

Use TSP, both work but TSP is better