ledger board bolted to brick wall

I recently pulled down the ceiling on the extension of my house to find that the roof (flat, joists perpendicular to wall) is built from 2X4's spaced 24" oc. I know this is not enough to support the roof. The boards are punctured right into the brick wall (it is solid double brick, no air space between layers) . I wish to fortify this structure.

Q1:
Can I use wedge anchors and anchor short ~2' long ledger boards between the existing 2X4s directly into the wall? I will then hang new joists off these ledger boards.

Q2:
The roof joists span 8.5'. If I wanted to put a deck on top of the extension some day, which sized joists should I use to ensure enough strength to hold the roof and a possible deck?

Thank you

 

It is fortunate you have an 8"+ solid masonry wall to carry the vertical load.

You roof support system (2x4s @ 24") is totally inadequte. Build a new roof with deeper, properly spaced 2xs. Attach these to a new continuous ledger attached to the brick wall. For your span, the loads are nothing compared to the vertical strength of the wall, but the connection is important.

Do whatever you can to provide some slope to the existing flat roof. Consider going higher by all means. If you go higher, look to see if it is possible to use through bolts for a ledger for stronger, more positive supplort. Through bolts are frequently used to provide strength/support/connections for walls in seismic areas.

This means a new roof for the extension, but few flat roof last long, so your may be near the end of its real life.

Dick