Not sure how to phrase this.. ceiling/roof trim appearing in my game a lot? Pic attached to show it

Ah, I've had that as well. The easiest way to remove that is by turning off the ceiling view (the green button above your funds). Besides that, it can show or not depending on your camera angle. You could experiment with it to have a view without it and still works for you. :)

Ya it just appears depending on the camera angle. It is a pain. If you are not opposed to using CC, you can get a invisible recolor of the floor edge here.

http://www.modthesims.info/d/459833/floor-edge-variety-pack-1.html

Old download but it still works perfectly fine, I have it in my game. Note you can only have one in your game, kinda like a default replacement. If you download, you will download them all, just be sure to just use one of them (invisible if you want it gone all together) You will also need to download the enhanced floor shader for it to work properly, linked on the download page under install instructions.

There's a little flower icon to the left of the video camera icon right above where it shows your household funds. Deactivating that would always fix the problem for me.