The houses destroy themselves?

your video card driver might need updating

Wouldn't that cause a fairly automatic problem, though? I've had the game for months without this happening.

do you have any cc from another site that you downloaded

That is weird! I've seen it happen to Sims, but never a house (or roof ).

I agree with rumbutter... it could be CC, I know when I had some bad CC, it made my Sims look  similar to the way your house looks.

ikr?  goodywood but i have seen simuliar issues and usually it's either a card needing an update or one going out but i am grasping at a straw here wondering if acc item could cause this ?

i have to search for crin's blog as someone had an issue recently with stairs/flowers going off like that to compare

found two links that be might  of interest to the op

found crins one i was looking for http://answers.ea.com/t5/The-Sims-3/Severe-Glitch-with-Stairs-Flowers-and-Fences/m-p/238416#M12511

http://answers.ea.com/t5/The-Sims-3/The-Sims-3-Graphic-Mistake/m-p/75864/highlight/true#M3673

edit to add might

Hmmm.... Now that I see the links... I'm thinking rumbutter could be right about that graphic card.

Do any of you know where I could find an update? I tried to use control center to search for one but it says my card is up to date, which it isn't.

if your card is an ati go to http://support.amd.com/us/gpudownload/Pages/index.aspx

if your card is nvidea http://www.nvidia.com/Download/index.aspx?lang=en-us