If you got other estimates for the job before you hired him, look at those. Ask him for a detailed breakdown of his “mistakes” so that you can evaluate whether or not you think it’s reasonable or just a shakedown. If you got other estimates, you can use those as a negotiating point for any price change agreement. If you are otherwise happy with the quality of his work, you may want to be more flexible and even generous so that he will be likely to come back if you need him to in the future.
Get him to sign off on any agreement so that he can’t place a lien against your property.

So - you only had something that was clearly marked as an "estimate" - and not a contract that included a price + scope of work? If you had a contract with a set price + scope of work, if he made a mistake estimating his costs, that's on him.

FYI - contracts can be formed through an exchange of texts - it all depends upon the wording. Contracts can also be implied in certain situations. (I'm an attorney - just trying to see if I can help you figure this out).

I'm surprised that for a renovation that you wouldn't have a set price for the work.

I hate working with estimates, since they always go up, but with you providing all the supplies I'd expect his to be bang on. Do you have a contract to fall back on?

His miscalculation is his expense. He should be at about half what he's charging.

Thanks, all!

He worded his last email 'estimate.' I never signed a contract. He refuses line item breakdowns, claiming that information is 'proprietary' to his business.

He is now stating that his invoice doesn't include material from prior work as he hadn't been billed by the electrician and drywall subcontractors, yet none of that is listed on this invoice. Nada.

It was listed on the prior one, so it looks to me as though he's billing for that again, though he insists he isn't and just didn't communicate that well enough. That the work listed prior was part 1 of 2 on those items, though he admits he didn't word it that way.

Also, his subcontractors who did the drywall damaged my garage door. He insists that they didn't, though he replaced one of the rails. When I arrived, we found a bolt lying on the ground. It turns out it came from the garage door. When asked, he said that he had it repaired because the door broke while the drywall guys were here - a month earlier. He never bothered to tell me.

For the record, I bought this house and had it renovated before moving in last month. I know that the garage door was not broken, and it had zero issues.

Worse, he left my house completely unlocked to allow free access to subcontractors. When I called him on it, he got mad and threatened to walk off the job. I gladly would have had my ceiling not been torn apart at the moment. No other contractor wanted to come in behind that.

Now, he doesn't want to email any further and wants a face-to-face meeting. I suspect it's because he doesn't want an email trail.

I think he needs to be reported to the BBB and the state board. But I also think he's trying to rip us off for around $15k. Not sure how to handle that.