What are the Implications of Allowing the Side Wall of our Extension to be Enclosed?

by: The Party Wall Surveyor


My neighbour tells me they want to build a conservatory which will be across the whole width of their house and length of our existing extension.

They propose to use our extension wall as one side wall – plastering their side.

What would be the implications of allowing them to do this?  Their builder has suggested they need to get permission from us.

They mentioned that they could build a wall against the side of ours but this would have access implications.

Would this create a Type B Party wall?  And what do I need to wacth for if it does?


Assuming that the side wall of your extension is your wall and not a party wall your neighbour would need to get your consent to enclose it. You are also correct to say that a ‘Type B’ party wall would be created if you allow that to happen.

Most Adjoining Owners would expect compensation for allowing a neighbour to use their wall – after all you paid for it in the first place. Although the Party Wall Act doesn’t apply as there is no right to enclose most neighbours would use the provisions of 11(11) as a basis for calculating the amount of compensation i.e. half the current day cost of building the wall and its foundations.


Is there a clear document somewhere that details the ongoing implications of becoming a type b party wall?  I am more concerned about this than about financial compensation for the wall – it has been built for many years.  I want to ensure I can maintain good relationships in the future with neighbour and don’t end up stuck with an issue further down the line.


The only document is the Party wall Act. Once the wall is designated as a party wall then your neighbour will have rights over it. The rights are set out in Section 2(2) of the Act.