how do i bridge the cavity for a new door threshold

[browfish]

I have built my extension blockwork and intend to install a coupld of sets of bifold doors. the walls are 2 skins of block work separated by a 90mm cavity. How do i bridge the cavity to create the threshold of the doorway? Obviously i can not jsut fill in the cavity and screed across.

I also have the same problem when i knock some of the old walls down to open up the extension. How do i bridge the cavity to create one continuous floor.

any help appreciated, thanks

 

[dann09]

Check out this post in the Building Forum:
"door threshold and cavity wall" ... sat sept 4 2010