This will be a classic Judge Judy, won't it!
What will happen will be he tells his story based on his viewpoint - the goods were fine and paid for implying acceptance by the purchaser with no obvious issues with quality. He will no doubt say you were unreasonable or not cooperative. You will have the opinion that his work was defective and substandard, and perhaps you'll even use the completed work from contractor 2 to place the substandard claim into focus in a way a third party can form an opinion. With two radically different viewpoints you need an arbitrator.
Will your evidence, or his be seen as solid, or will it be a on the basis of probability? Who puts the most likely compelling case? Could those materials have been identified as substandard visually? If so, payment tends to wipe out that part of the claim. If the problems were invisible - maybe internally rotted timber, for example, the court could side with you. You might end up with a bit of both. As communications has broken down self-arbitration will be very difficult or impossible, so both sides will have to put their faith in the court process.
It's not really right or wrong, it's down to the evidence both sides have shifting the decision from him to you. They'll ask you what he did that made you decide to cancel the contract. Will it convince a third independent party? Is it an opinion or fact? Could he have reasonably known the products would weather badly - and what exactly constitutes 'weathering'. Some timber changes colour, some leaks sap and others go unusual colours, wanted or unwanted. If you have part of an email where you asked if the timber will go silver and the response is no - this wood will remain the same colour, then that's good for you. No doubt he will claim your payment for the supplies is an indication of satisfaction, and unforeseen issues are not his fault?
This is what makes me label it a Judge Judy case. Three people's opinions and just one counts, hers. You changed his faulty work. You will have to explain what exactly got changed. Work you had done that is outside of what was originally requested may also not be allowable. Did you give him the option to put it right? Did he refuse and say why? This will all come up in the court. He might maintain he did exactly what you asked for and you changed your mind? Best of luck with it, but unless he simply rolls over, and it sounds like he feels you were the customer from hell, then two people will have to simply let a third decide. I'd suggest you look hard at the evidence you have, and maybe try it on somebody you know who will be willing to give and impartial opinion? If this person struggles, so will the court.
Thanks for all of the above.
Its taken careful consideration for us to get this far, I would normally let something like this lie, however, based on the financial impact its had on us, we're finding it tough to take when we really aren't in the wrong.
Some of the work is still in the same state it was in when the original contractor left, this in particular is some composite decking, which is also the same part that we are currently not happy with the 'weathering' of. Its visibly changed colour and is advertised as 'UV protected' etc, its the reason we went with that and not timber decking, we have photographs of its appearance during installation and now 1 year later, obviously in agreement that this isn't his fault, but his responsibility to resolve.
Furthermore, we signed off on the decking at the time, since then we've had multiple contractors within the industry come and look at it and they all agree that the work is not to standard, as-well as the fact that the materials are defective.
Regarding the rest of the work that we had rectified by a superseding contractor, we have lots of photo's and video's of the work in the final state that it was in when he was taken off the job, and in parallel, photos and videos of the work now in the state that we are happy with.
In addition to all of this, further evidence that could help our case, we had skips dropped directly on our drive (no pallets or runners) without consulting us, these have damaged the driveway, furthermore, he damaged some exterior to our property and on more than one occasion, when entrusted with a key whilst we were at work, failed to lock the property when leaving. All of that could be considered hearsay, however, we have conversations with him that we have screenshots of to back that up.
My view of all of it is that, he's out of pocket RE not being paid labour and this is solely his fault, I'm out of his pocket due to having to purchase materials twice and that's also his fault.