Hi
I need to replace the siding on my chimney.
It is currently a light-weight particle board.
I am planning on replacing it with Hardie-planks which are much heavier. Is the additional weight a cause for concern? My chimney is about 8-10 ft tall.

Thanks.
-KT

Light-weight particle board is the finished siding on your chimney?? That sounds really lovely. The ability of the chimney to carry the fiber-cement siding depends on what the underlying support is. More than likely, it's OK, but without knowing exactly how the chimney is built, more cannot be said.

Is the siding (particle board) the sheathing or the siding?
Some construction methods utilize the plywood as part of the structural construction. If this is the case you need to re-plywood the framing before you re-side. If the framing was done properly there should be no issue to use the hardi-plank on the chimney.

But you should be sure to nail this product on even walls. Check with a string from corner to corner to see that all the vertical studs are even. If not pack out the wall to make it even. The hardi-plank is so thin that any uneveness of the wall shows up fairly easy.

It also should never come incontact with the shingles. It's suppost to be 4" up off the roof line.
Prepaint it before installing so there's less chance of paint getting on the roof.
Use vinyl lumber to trim out the outside corners not Hardie trim. I have two dealer that refuse to even sell the trim any more due to brakage when trying to install.