Joining walls to roof

[dutch1]

Hi,

I am currently doing an MEP project and I am tidying up the model at present. 

I am having problems attaching the walls to the roofs. There could be a simple solution but I havent found it yet !!

I have tried attaching top base etc. but its not working. I only seem to be able to select one side of the roof when selecting where to attach the walls.

I have attached 3d pics showing the walls that are extruding & also one of the walls that I am trying to attach.

Any help is appreciated !!

[constantin.stroescu]

as I can see in your second screenshot the selected wall does not show  the small blue arrow pointing upwards in its upper side _it has only the arrow in the bottom pointing downwards. That means that the wall is already attached to another entity (could be a floor). Detach this first...when the upward arrow shows then you can Attach to roof

[dutch1]

thanks for your reply constantin.

When I highlight the wall, the blue arrows appear at the top & bottom of the wall & can be manipulated up and down. When I select the attach top base option it asks me to select an object(Roof in my case) to attach my walls to. I can only seem to select one side of the roof you can see in the drawing Im starting to think this could be the issue but the roofs seemed to be joined already,  AAAAAAAHHHHHHHH !!