How do you connect rooms together

[Tolomea]

I'm trying to build my first base and can't figure out how things are supposed to connect.
I have a basic corridor built and I want to add a cross corridor like this http://steamcommunity.com/sharedfiles/filedetails/?id=1283682645 but it won't let me.
However it is fine to let me place it a block higher or lower, just not connected
http://steamcommunity.com/sharedfiles/filedetails/?id=1283682723
http://steamcommunity.com/sharedfiles/filedetails/?id=1283682756
What am I missing?

[Amanoob105]

Do you have something built inside the left half (as show in your picture) on the one you built first, if so it is likely getting in the way.

[Gregarius]

You need to build Foundations - the very first structure in the list. You can build one structure without one, which is why you see green in the bottom two screenshots - the game thinks you're just building one structure. Build a foundation in order to connect a lot more.

[Demolition414]

yeah check that theres noting against or near that back wall, no lockers, fabricators or anything like that,

[KHAN]

no, you dont need an fondation to build on, but i thing the first section is to high up, thats why you cant contect a secont section, try and puild closer to the bottom

[Demolition414]

Originally posted by KHAN:

no, you dont need an fondation to build on, but i thing the first section is to high up, thats why you cant contect a secont section, try and puild closer to the bottom

it cant be the height if they showed they can place a section above it.

[Tolomea]

It'll be the damn lockers, thanks I will give that a try in the morning