Our house had a detached garage originally.
Many years ago, the previous owner decided to join it onto the house and add two bedrooms above.
We were given permission to build a larger and wider garage directly to the front of the original one, which is now a single bedroom.
This was entirely satisfactory when we had three sons living at home and well worth the effort and expense.
I now plan on using some of the new garage space as a utility room with 8m2 to play with of the old garage.
I see this as straightforward except that when the original house was built, the drainage inspection chamber was moved into the garage. If I go ahead and knock through to the house, the floor level will be raised and I need advice on how to deal with this inspection chamber.
It is not a branch but turns toward the external sewer. If possible, it would be preferable to seal it completely.