Building contract for extension? needed or not

Building extension to house, approx 45k, is there a need to sign some sort of legal contract for this, I know I did when I built the house but obviously that was a much bigger build. Is it sufficient to get a detailed quotation? If not is there a specific type of contract for extensions and do you have to go through solicitor to do this. Appreciate any advice available.

definately, to ensure all matters relating to cost/vat are in writing, no to mention date of completion, method/stages of payment etc etc

Thanks. Is it something that has to be done through a solicitor or is there a standard form that you can get somewhere?

I'd say there is no need to get a contract signed. I would say it in writing to your builder that the contract is to be carried out under the terms and conditions of the RIAI without quantities contract when asking for their price. There is no real need to sign a contract then, if it were to go to court then the terms of the RIAI contract would apply. I would get your builder to give you breakdown on price prior to starting and also a programme.