I often thought along this after reading a reading a Artur C Clarke story about a space ship with a huge ice shield protecting it from impacts...
Maybe this is an idea for you also......
Ice Wall ( a sculpted block of ice with some wood(chips) ( see Pykrete) made in the chemical plants), obtain able relatively early in the space branch
Could not be as resistant as your hull, but would be easily obtainable in space and also sort of repairable on the go
Could be even a makeshift spaceplatform ?
