Template for Letter of termination of contract

[creamcheeseandlox]

We are get getting to the point where we may need to terminate/fire our builder. He is 5 weeks overrunning on a job which shouldeasily taken 6-7 weeks, won't finish the work we have paid him for and has not stopped responding to our messages/calls. It's a long story which I don't particularly want to go into but does anyone have/know where I can find a template for a letter terminating the contract.

Do you actually want to terminate the contract? - could it come back and bite you. What do you want to achieve - action from him, money back, freedom to appoint someone else?
Rather than firing him, would it be better to write the letter firmly putting the blame on him and pointing out the fact that he has voided the contract. Use the terminology of the contract to write the letter for you ("you failed to do xxx in accordance with section 5b, so under clause 14c we hereby blah blah")
Don't forget to include time scales ("if we have had no response within 14 days then ...")

Sorry I meant a letter stating a deadline and if the works not completed by x date etc.

Wasn't sure if there were any examples I could look at.