so, i have an issues in my map where my grass texture brushes are allowing light to pass through them and you can also see any windows and glass in the back ground through i think it is also happening with water aswell .

i have an example of a garden hedge i made (dont ask but the best texture was a grass one)



any ideas on how to stop this and make the texture "solid" so no lihgt will pass through

The picture you uploaded is somewhat hard to see but I think the issue is you are using blend textures. In radiant there are a number of textures with a suffix of "_blend". These are used for alpha blending and when used in the way you are using it allow things like light and FX to shine through them. To correct the problem find the version of the texture you are using that does not have the "_blend" suffix.

thanks mate sorry for the quality of the picture.