Gaps during winter is a common occurrence. Do you know the humidity levels in your home? For a solid floor they should be between 30% and 50%.

They may close up, but then will reopen the same time next year. Gaps can be a problem with any wood floor, but the more extreme versions of it often occur because the flooring was not set out to acclimate to the humidity of the living space long enough before the install. If the area it's to be installed in has lower humidity than where the flooring was stored, the boards will shrink as the moisture goes down. Storing them in the living space, perhaps for several weeks will allow them to naturally shrink and any gaps that show up after the install will be less noticeable.

Wood is hygroscopic. It expands and contracts with moisture. Summer high humidity conditions cause expansion. Winter low humidity conditions cause contraction. That is normal behavior for wood.

Without an idea of the scope of work of the lroj ct, the timeline on your installation, recordings of the moisture content of wood and subfloor at install and now, and pictures of what you are dealing with, no one can tell you if what you have is normal or abnormal.

Where did you find your GC? Where did he find his wood specialist? What was the overall scope of the job? Square gootage of flooring involved? Price paid for the flooring portion?

Did the flooring sit in your house and acclimatize to the humidity levels? Basic flooring 101. If they didn't, your GC and flooring guy have a lot to answer for. If the gaps close (big if) they may open back up in the fall/winter. Tear out and do over. No floor should have a crack wide enough to put two quarters in. If they won't do anything, it's time to get out the social media and carpet bomb them.

You can start a small claims against him and see if you can put a lien on his property or business. Go after him on his and your facebook pages, as well as yelp and twitter. You gave the money to him so he's ultimately responsible.

Never, ever, ever go with a "friend of a friend" who you haven't vetted and gotten referrals for.

It’s your GC’s issue. Your GC needs to solve it. You’re going to lose that friendship if you insist on that, but it’s what you paid him to GC for.

Do you have a written contract for the flooring install, or was this done on a verbal agreement/handshake? If you have a written contract, you may have some legal actions you can take. If no contract, you're dependent on him pulling his head out of his arse.

If he doesn't have a real company, does he have a license? I'm not sure about all states, but here they need a license. Check with your state contractors license board. Here, you can sue unlicensed contractors and get a judgment to get all of the money back that you paid to them, just because they are not supposed to be working without a license. I don't know about where you live, but it's worth checking into, imo.

If you handed the cheque to the floor guy, you are responsible for his work. Even if the contractor found him, you paid him. That means you are his DIRECT supervisor/project manager.

To keep yourself in the clear, you need to pay the GC...and then the GC pays out the subs. That is the CLEAR PATH. The path you took meant the GC has NO NEED to do anything further. His hands are clean.

The person who PAYS THE SUBS is responsible for their work...regardless of who "found" whom. There is a REASON why your "GC" (sorry but he isn't a GC if he didn't pay the subs) did this. It absolved him of any/all FINANCIAL liability. Sigh.

I'm sorry but you've been caught out in a legal 'no man's land' on this one. No contract and NO GC to payout the subs = you became financially responsible for the subs...and their work.