So I recently got back into map making and I forgotten a lot about using radiant so I'm trying to relearn it at the moment... so I have this problem where I made this texture blend in asset manager to make it transparent and mix in with the texture behind it. But for some reason it is going completely through and showing the outside of the map instead of blending in with the texture behind it. Why is this happening? How do I correct it?
Picture for reference...

Move it down 0.25 units on the absolute smallest grid so it is "infront" of the the roof but imperceptible to the eye that its not flush while people are busy shooting zombies, nobody will notice and it will look great. Show a picture from the same angle after you moved it down a tiny bit in radiant.

Your advice worked thank you  ! After not using radiant for about a year I became a newbie at it again, so I'm slowly relearning it all. Oh and I kinda gotta crop out the extra stuff on that texture's edges so I'll get to that. Thanks again!

Nice, looks like intended now! i usually hate messing around in asset manager & do everything to avoid it, including manually offsetting textures