Sims3DreamHouses posted a question about finished attics on the Building and Construction board
here.
That prompted me to build this as an example. I know it's not exactly what he was hoping for but it's the best work-around I've been able to come up with for finished attics.
I've tried to limit myself to Vanilla Sims3 base game content for the most part. There is a fuzzball table from Late Night in the attic. But just in case I slipped some other things in there by mistake the EPs I have are Late Night, Ambitions and World Adventurer. I never use custom content or store content so pretty much everybody should be able to use this.
Even if you don't have Late Night I think the game will just replace the Fuzzball Table with something else.
The furnished price is $85,203 simoleans. For some reason I couldn't get it to show me an Unfurnished price. Oh well.
As I said in Sims3DreamHouses's post I use the flat-top half-wall near the edge of the attic and just play with the roof pitch slider until the roof exactly meets the top of the half-wall.
You can just barely see the edges of the top of the half-walls just slightly visible outside the roof in the image below.
I could have hidden them completely just by making the roof pitch slightly steeper but I left them a little visible for the purposes of this example.
Here you can see the inside of the attic which I made into a kind of rec-room for the kids.
You can put up some temporary full size walls just to be able to put floor tiles above them that can then become the ceiling of the attic. You can the delete the full size walls once you have your ceiling tiles in place.
Here on the second floor we have two bedrooms, a nursery and a bathroom. I used a wall lamp with intensity set to dim as a nightlight in here because whenever a toddler wakes up in the middle of the night he's usually already in a bad mood and we don't need that "It's Dark" moodlet making matters worse.
Here on the first floor we have the master bedroom, kitchen, bathroom, living/dining room combo and an attached one car garage.
I love that TV and fireplace combo. That's the only TV and the only fireplace that can occupy the same wall space at the same time as far as I know. A heck of a space saver. The only caveat is that if the TV breaks it can't be repaired where it is. The sims can't get to it to repair it so you just have to go into build mode and temporarily move it someplace else so your sim can repair it.
Here's the rather large basement that I didn't do anything with. It runs all the way under the garage and was made with the regular basement tool so it does count as a nectar cellar. You can eve throw a couple more bedrooms and another bathroom down there as the family gets bigger.
The backyard feels kind of small to me but being on a 20x30 lot should make it easy to find places to put this little family home.