Having the same issue.
A few thoughts that may or may not be relevant for either of you...
If the ceiling &/or floor are missing, they can be added as follows:
Build Floor:
1. Click a wall on the room. The room should highlight.
2. If the floor is missing there will be a yellow rim around the floor.
3. Click the yellow rim and there will be a popup that says “Build Floor”.
4. Click the phrase “Build Floor” and the floor will be created by the game.
Build Ceiling:
1. Click a wall on the room. The room should highlight.
2. Use the ▲ arrow to go up a floor/level.
3. If the ceiling is missing there will be a yellow rim around the ceiling of the room below.
4. Click the yellow rim and there will be a popup that says “Build Ceiling”.
5. Click the phrase “Build Ceiling” and the ceiling will be created by the game.
Tip: If the room does not highlight when you click the wall, the game may not be seeing it as a room. To fix this please retrace the room with the wall tool. Sometimes this fixes the issue. You can confirm by clicking a wall in the room and seeing if the room now highlights.
I do play with Mods/CC.
That is carpet. I mentioned it's indoors, why would there be snow? And I guess because that sim likes to swim?
I do not believe there is an issue with the house.
Thank you for the information.
I mentioned snow since I have seen times where snow was inside when a room was not sealed or buggy. I mentioned swimwear since there have been times that I have found my sim was cold or worse, even inside with heat on, in (swimwear or) a pool, in particular during 'very cold'/(maybe also blizzard?) conditions outside. Also, as I mentioned, this can happen if the room is not properly sealed.
Personally, I removed the effects of temperature in my game a while back when there were random issues with them freezing, and putting winter clothes on automatically when outside in cold weather. I think this is not an issue now, but I cannot tell you for sure. If you check and the weather is not severe, and the rooms are properly sealed, and the sim is wearing winter clothing and they are still behaving this way, you may want to test without the mods and cc and see if the issue remains. The fact that you said your sims are also 'slipping' inside like they are falling on ice makes me wonder if it's either a non-sealed home (and possibly severe weather) situation or a mod/cc issue.
If this is the only issue you're seeing and you care less about proper weather sensitivity than your Mods/cc, you could see if deactivating their sensitivity to temperature in settings solves the issue for you.
