I have some beat up hardi panel and trim on the outside of my house, and was wondering if it is ok to sand this stuff (besides the hazard of breathing it). I want to even out some spots that are fraying re-prime and paint.
Should be fine if you wear a dust mask.
Posting some pictures so we can see just how bad it is would be nice.
If it's falling apart where there's end cuts it's because someone did not prime and paint it as should be.
Also if it was installed any closer then 2" to any solid surface EG; roofing, grade, deck, stoop, it's going to fail.