Flat roof addition - Joists connected to structure via legerboard??
We have a flat roof addition attached to our 40 year old house with a peaked roof (the addition was built before we purchased it). The addition has 3 exterior walls sitting on a cinderblock foundation, and one wall that is shared with the existing structure.
The flat roof is 16' wide, composed of 2x10 @ 16"oc. The roof of the addition is 2 feet lower than top of the existing wall is shares with the house, so the roof joists could not be positioned on top of the existing wall. Instead, they have been attached to the existing structure via a ledgerboard screwed to the brick wall, with joist hangers supporting the roof joists.
We have noticed some cracks in the drywall, and a large crack in the foundation (which has been repaired) My assumption is that this roof design provides no vertical support for the roof on one side, and it appears that the entire addition is slowly pulling away from the house, and taking a portion of the house with it!
We called our home inspector, who came out, had a look, and insisted that the ledgerboard is fine for connecting the roof joists to the existing wall, as long as lag bolts are used to secure it. Has anybody seen a legerboard used in this way before? Is it a suitable building practice?
Any thoughts would be greatly appriciated.