Sealing an outdoor map

[little wind]

First time ever working with Hammer, has certainly been a learning experience.

I have a small outdoor map with a few buildings, though the outside map stretches on for quite a bit.

I had an issue with vis when the map wasn't sealed, mainly seeing the outside while inside the buildings, but sealing it causes the environment light not to shine through it, making it basically completely black. Flipping the normals didn't work, but caused all kinds of weird lighting issues.

How would I go about sealing it off? How much of the map to cover and with what material/settings to get the light to come through?

[foggy prairie]

use toolsskybox to seal the sky (grenades will pass through)

[little wind]

The same issue is still present. Am I supposed to texture it with the skybox material or leave it as is? And normals should be inwards, correct?

[little wind]

And any particular properties I'd need to change?

[alpine shoal]

think you'd need to post screens of hammer to show what you mean

maps just need to be sealed with no solid faces facing out to the void