Extending a flat needs freeholder’s agreement on paper
Firstly, you will need to tell the freeholder that a new lease by way of surrender and re-grant is required incorporating a plan to Land Registry acceptable scale.
Ordinarily, a freeholder would charge a consideration payment for this new lease as the additional accommodation will add considerably to the value of your property.
However, as the freeholders have agreed to the loft conversion which has been carried out and are relatives, I assume they may forego such payment.
An accurate plan detailing the loft accommodation will need to be prepared by a surveyor to a Land Registry acceptable scale, usually 1:100. This forms the basis of the new lease and will be referred to in that document replacing the plan to the original lease.
The new lease will detail the parties being the freeholders and yourself and any coowner. It will detail the existing lease. The description of the accommodation describing the flat will be altered from the original one level to include both levels and loft conversion rooms. If it is desired to also extend the term of the original lease, for example if it only has a relatively short term left to run, usually less than 70 years, a new term can be granted within the body of the new lease.
Again, the freeholders would usually charge for the granting of a new term as it adds value to and increases the saleability of the flat.
This new lease will need to be prepared by the freeholders’ solicitors and I would consider it only fair that you agree to pay the legal fees for this.
After all, you are obtaining a financial benefit of not having to pay a consideration for the new lease.
Once approved and signed, the new lease will form part of the contract package produced by your conveyancer to send to the eventual buyers’ conveyance. If your flat is subject to a mortgage the new lease can be legally completed contemporaneous with the sale of your flat avoiding the necessity of obtaining your lenders’ consent to it.
However, to avoid any delays it is important the plan is prepared, the new lease drafted and agreed and hopefully what could have been a major expense to you will be simply be an administrative legal exercise.