Problem with Holes in Meshes After Colliding

As I understand you’re using BSP brushes. If so then you can convert your brush to a static mesh or change the order of the vertical support.

296305-bsp.png

I took a simple geometry square and started building and shaping. I am not adding detail to my attic and putting meshes together and having them collide but doing this makes random holes come up in my meshes, how can I fix this?

Thank you so much! So simply and clear!

Question, I see that after I set the geometry to a static mesh, I can only select the mesh as a whole and I cant pick each side of the static mesh like I could if it was a BSP Brush, is there any way to give the static mesh the ability to add materials to each side of the static mesh and not just the whole mesh itself?