wood shed suggestions

so I figured since we'd be "camping" out there more then once, I picked up one of these
the bottom is a couch, that pulls out into a full sized bed, the top is an twin size bed

the whole thing should be a lot of fun for the kids, and a whole lot less work for me then having to haul inflatable matrasses out there each time

there is only one problem

the top bunk sits pretty close to the top
still no big deal...except...someone used 1 inch roofing nails to nail the shingles down to the 5/16th particle board...so there are more then a few 1/2 nail sections exposed for the kids to scratch their noggins on

I think i'll know what my next project will be...hammering each and every one of them flat