If you want to eliminate roof access, you can also remove those stairs and open that area. It would be a good spot for a crib or pet mat. >_> (just put down some floor strips to "close" it) The lot as it is, is easily affordable for 8 sims moving in, I think. Since 8 sims in the bin get what? 56,000?

I edited my reply to you over on BP with something I forgot to add before. Not sure if you've been over there to read that yet!