UKC

As title, will it damage the shell due to the extra creasing?

TIA, Mark.

Not at all.

Many of the lightweight shells available now come with their own little stuff sac, that is often pretty tight. Never heard of anyone having issues with waterproofing after compressing gore-tex or other membrane fabrics.

Stuff it rather than roll/fold it, so that you don't get neat creases in exactly the same place every time

Ok Thanks.

Good point, cheers.

Surely the stuff sac is designed to keep pack size down in use, rather than long term storage?

I don't know for certain, but I'd imagine that keeping what is essentially a thin plastic membrane creased over for an extended period won't do it a lot of good in the long term.

I wouldn't store hardshell under compression for extended periods of time. A week away, no problem. 8 months under the bed? Not so sure.

BB

Very true and a good point. My assumption was that the op planned to have it packed in a compression bag whilst away on a trip or somesuch as opposed to long term storage. 

Don't store it stuffed. Honestly, the best way to store jackets, even hard shells, is to store them hung on a coat hanger. Stuffing anything like this does damage the face fabric over time, repeated stuffing that is. Stuffing once and leaving probably isn't so bad, but I'd always try and hang them if I can.