Breaches in the structure of your base are a serious problem in Breathedge. You will find out how to prevent them below.
To stop Breaches from occurring in the base structure, you will need to craft Protective cover. It is a structural element (you'll find its blueprint in the Dispenser once it's been unlocked), which is built on the outer walls of the structure.
To find the necessary blueprint, float to the other end of the cave, bypassing the communications module.
Here you will see two wrecks. The second one, near the asteroid, is the one you want. Inside, you will find the protective cover blueprint. You will learn the blueprint by scanning the cover.
It's best to place the cover on the corners, where no other structures are located. You don't need much Cover, because it provides a large defensive boost. To build Protective cover, you will need 2 units of lead.
If breaches have already occurred, you will be notified about it remotely. There will be holes inside the base that you can repair. Use the Research table to discover chewing gum (components: resin x4), which can be used to fix the breach (later, chewing gum can be crafted with resin x1).