Can We Insist on a Gap Between our Neighbour’s Conservatory and our Wall?

Question

We live in a link detached property where our neighbour’s garage links to the side of our house with a space behind their garage.

They have written to us using the party wall act saying that they would like to utalise this space and build a conservatory behind their garage which would mean that one side of the conservatory was one side of the remaining part of our house and the other being their house.

We have signed to say we are in agreement subject to further information, however now reading further into this, is this really a party wall or does this stop where their garage ends.  My main concern is that we bought the property as a link detached property but would this then be classed as a semi-detached and in effect de-value ours.  Can we stop them doing this?  Or can we insist that a gap is build between the conservatory and our wall and if so how much gap should be provided based on ensuring damp proofing etc.

Answer

From your description it would appear that the part of the side wall of your property which your neighbour’s garage encloses is a Type B party wall (see this article for the 2 types of party wall). The rest of the wall would not be party and as such your neighbours will not have a right to build up against it without your consent.