New life for old tires
Another way of providing additional seating, especially if you are dealing with a smaller space, is this ingenious DIY idea. All you need is some rope and a tire, preferably one that is no longer needed!
Fix a plywood round to the top and bottom of the tire, glue 4 feet to the base. Then wind the rope round and round, gluing it down as you go, making sure each strip is close to the one before. You end up with a chic and sturdy coffee table or seat that looks like you spent quite a lot of money buying it.