I would like him to acknowledge that there are elements of the contract that have not been fulfilled therefore there must be some off setting between works not completed and extras charged for particularly as no prices foe extras were forthcoming before he undertook the work, in itself a breach of the JCT
Thanks. If you have not agreed to extra works the builder is demanding then there is no liability to pay for the same.
You will wish to consdier giving the builder written notice of his breaches of contract by way of a schedule of defects and reference to which stage of the contract the defect relates to; if there is provision in the contract for obtaining interim architects or inspectors certificates you can also refer to failure to obtain such interim certificates and putting him to strict proof in relation to your agreement in respect of those "extras". The burden of proof is upon him to demonstrate that you agreed to any extra work for which he is attempting to charge.
You may consider inviting him to undertake to you that the work will recommence and a timescale for completion. If you have on you may wish to have the architects support and assistance in preparing a schedule of outstanding works if you do not already have this. You may remind the builder of any verbal dates that were given for completion and failing which remind him that the Supply of Goods and Services Act provides that in default of a date being agreed between you the Act provides that work must be completed in a reasonable time.
If the builder ignores the above or does not satisfy you with his proposals you can issue a notice indicating that you are dissatisifed with the work as it is not of statisfactory quality by particular reference to the above schedule of defects nor is being completed in a reasonable time or in accordance with the timescales verbally agreed. You can advise him that you are making time of the essence and that unless he contacts you within 7 days with improved proposals you will instruct a third party to quote to complete the contract and look to him for any difference between his costs and the cost of completion as provided by a replacement contractor.
If he continues to ignore this then you may go ahead and obtain quotes as above. From there you can either go ahead with the most cost effective quote and then claim against the original builder after work is complete or pursue a claim against the original builder before instructing the third party.
It is important that you keep correspondence you send to the builder as it will be required to demonstrate that you both tried to resolve your dispute and to demonstrate that you gave him the opportunity to complete the works before you instructed a third party.
You can either use the dispute resolution provided for in the contract. RICS also offer a dispute resolution service if the builder will agree to the same:
Alternatively you can resolve the matter in the county court for which you may need an experts report - e.g. your architect or a surveyor. THe simplest way to issue proceedings is by using www.moneyclaim.gov.uk
Is there anything above I can clarify for you?