Broken down bikes take up much less room than built ones.
Loft is good, not sure about racing frames but I can get 20" GT frames into the loft
without too much hassle. I have a load of hooks (with padding) with frames hung from rafters
and my loft is by no means huge. I put the components for each bike in an empty beer crate box.
I have a stack of wheels in the loft (and the shed), pile them up with something between
each one. Tried hanging them on strings in the shed but they kept banging each other.
Found this is the key to storing (I have over 20 in a small house/shed !!). You get pretty quick
at assembling one to ride, I rotate with a couple to ride and one building.
Wheely bin bags (the great big ones from Tesco etc) are perfect for putting a dirty frame & forks in to move about/store.