metal siding for 3 story barn

[EddieWalker]

Don't do it. I know it's going to be less money, but it's also going to be ugly and something that you will regret in the future. Either wait until you have the money to do it the way you really want it, or use a different material that will give you the same look, but less maintenance.

I'm a big fan of James Hardi products. They sell 4x8 sheets of cement fiber panels with cedar wood grain on them for $26 each at the box stores. They also sell cement fiber battens that will give you the same look as wood, but never rot and nothing will eat through it. It holds paint very well and if you use a decent quality, shouldn't have to paint it again for the next 20 years.

Eddie

 

[E_Sanborn]

You can certainly use the metal if the look suits you. It's fairly common in this part of Texas to see barns, shops and outbuildings using corrugated metal roofing as siding. Good news is that galvanized roofing lasts a long long time when properly mounted as siding. Galvalume even longer.

I've used recycled metal roofing as siding on my shop and sheds, looks kind of post-industrial, but very durable and really helps with the extreme heat gains in summer.

I think you'll be ok with existing sheathing and siding as long as they're sound.
What I did in my case was new construction, but all the same: on top of sheathing, lapped 30lb. felt, lapped 6", then ran 1x4 treated SYP vertically on studs, 16" o.c.; then 2nd layer of 1x4" treated SYP, 24" o.c. (rain screen); then screwed recycled tin 8" o.c. Keeps much cooler in summer and a little warmer in winter. I particularly like the fire resistance it adds, don't know if that's an issue for you.