Masonite siding has several law suits in the works so do not know if is even available? May want to go to www.google.com and search for Masonite siding and see what come up.

Go to a lumber yard and they will have hardboard siding there. Masonite is just one of many brands of this type of siding.

Be sure to prime the back and all edges before you install the new siding and then apply at least 2 coats of an exterior acrylic house paint to the face of the siding.

I too need to replace some 3 panel flat (not lapped) Masonite siding. I have not found any other brand with the same pattern. I would love to Hardy board but nothing matches what I have. It is 12" wide and came in 16' pieces. Each piece has three panels. One of the local lumber yards had a few pieces but they are out now. Somebody needs to produce a look-a-like product.