Cement board or Hardy side type products were the only types of sideing to hold up to the golfball/hardball type of hail we recieved late last spring. Steel siding was dented up and vinal sideing was splintered/shreaded off of the homes.

When you are installing the sideing, be sure to "flash" under the joints. Ask the cement board place you buy it from to explain the installation to you. The flashing is something like a 6 or 8 inch wide by a few inch taller then the sideing, piece of felt paper Tyvac ? (see Tommy's post below) that sits behind the sideing joint, over lap onto the bottom piece of sideing. If any water gets in the joint, it then moves down the felt out the bottom onto the face of the next piece of siding. . . .clear as mud ? Most do not caulk joints, most use the epansion joint filler clips . . .