Can't make a part of house count as indoors

[Paulo2400]

I'm building my first house from scratch in a forest area that I've cleared. It's based on a very practical base that @WillieSea built.

I've built the entire base with the amazing brush tool in debug mode. Everything worked great, but there is one problem, see pic:

https://imgur.com/a/ZaKUV9v

The house has only one floor and a flat roof. The white area is all enclosed and counts as indoors. Temperature in that area is higher than outside and sounds are muffled. The blue area is a generator room which has no roof, so it counts as outside, which it is meant to be. The green area is again completely enclosed and has a roof. It's the same build method as the white area. So it should be an inside area, but it isn't. Rain doesn't come in (because of the roofing), but temperature and sounds are as if outside.

I can't figure out what I did wrong with the green area. I have specifically paid attention to the building method of the walls, so no extra pillars are built, only a pillar on the bottom corner of the green area. I have also built this section from bottom to top and have built it several times over again, to make sure that I didn't forget to build a wall piece or door frame. The blue generator room with open roof is adjacent, so could that be the culprit?

Hope you guys can help. And @WillieSea: thanks for the inspiration!

[WillieSea]

An interior space can be broken for many reasons.

There is a 'post' stuck in one of your walls. Use the 'delete' tool to look for it. Press 'R' to cycle through the items in the cursor cell to see if a post is present.

Usually what I do in this case is start by destroying one whole side of walls. Then rebuild.

To build walls correctly, start building from the bottom and work upwards. If you build your wall from the top and build downwards a post is sometimes inserted into your wall causing the problem.

[Paulo2400]

Originally posted by WillieSea:

There is a 'post' stuck in one of your walls. Use the 'delete' tool to look for it. Press 'R' to cycle through the items in the cursor cell to see if a post is present.

Thanks, I'll check whenever my save gets unborked again.

[WillieSea]

I also use the build tool to make the floor, walls, and ceiling. Then if you need to use the debug brush tool, use it over the built area. Because I don't know if placing walls with the brush tool is the same as building a wall.

[Anna]

I fixed it couple times by spliting the room in half with additionall internal wall. It split the are to two rooms one will be "inside", another - "outside". Repeat the same with the "outside" room till all the rooms are "inside". Then - destroy all internal walls.

You don't need to build full walls, wall-frames should be enough.