It's all very well for you to do your own work and have fun and confidence in doing it but Ray from what he has said doesn't know a joist from a jester.
He has a modern brick built garage with a tiled apex roof which will have a considerable amount of weight.
We don't know any more than that.
Neighbours objections, substrate, certification for resale etc all should be taken into account before saying shove a bit of wood through a hole and prop the roof up on that.
No good putting acrows directly onto clay and proping it up with a lump of architrave, not saying he would but lets have some prospective here.
Don't forget these are public forums.
