My contractor left a 1/8th inch gap between the cross-beams and support posts of the deck. The beams are only attached by bolts. He said he would remove the bolts and let the deck weight drop it down to the support posts. Should I be concerned that will torque pressure on the deck and house?
The answer to your question depends on two important factors:
1. What is the weight of the load being held up by the cross beam?
2. What size bolts did your contractor use?
For example, I wouldn't be overly concerned about a small deck load that was supported by several premium grade 5/8-inch carriage bolts and a couple of 1/8-inch steel "T" brackets, but I might be concerned about a significant amount of weight resting on just a few 3/8-inch lag bolts.
Backing out the existing bolts and letting the load settle would allow the cross beam to correctly rest on the top of the vertical post, but keep in mind that if you do this you may run the risk of tweaking some other portion of the structure. Of course, if your deck only needs to drop 1/8 of an inch, then perhaps there is enough give in the framing to let it settle? What you definitely don't want to happen is for the deck to drop so much that it compromises the connection between the deck and the house, or worse yet, the connection holds strong and transfers the deck movement to the wall of the house, which could crack the interior sheet rock or damage the wall framing.
One possible solution might be to use some shims to fill the existing gap between the post and the beam. This would allow the deck and bolts to remain in position, but would put in place some solid support where its needed. Using plastic shims would decrease the possibility of the shims compressing over time and if installed right they could help transfer the deck load to the underlying support posts.
If this gap is in a highly visible location and shims are not an acceptable solution for your problem, then you may have to just replace the existing post with a new one that fits. Although this fix is probably the most difficult and expensive, at least the post and beam connection would done correctly. Good luck with it!