My Neighbours Have knocked a Hole in the Party Wall for their Fireplace

Question

I live in an old house (Victorian). At some point in the past (before I bought my property) a house was built onto the side of my property, thus changing what was a semi-detached house into a terraced house. 

When the house was built onto the side of my property, the builders did not put up an extra wall, they merely used the exterior wall of my property as the interior wall of the new property, to which they added plaster and wallpaper etc….  

It has come to my attention that recent owners of the house have knocked a hole through this ‘party’ wall from their front room into my chimney (without informing me) in order to install a decorative fireplace into their front room. These owners then sold the house to my current neighbours. 

My questions are

a) were they entitled to knock a hole into my wall and join their fireplace to my chimney?

b) I have noticed that my chimney is no longer drawing as well as it used to and smoke comes back into my living room if I light a fire – could this be caused by the hole in the chimney wall?

c) will the hole have weakened the wall which is very high (3 storeys) and has a chimney stack on the top ?

d) can I oblige my current neighbours to block up the hole? (they never use the fireplace). 

I hope this is clear and I hope you are able to provide some advice as this is a very irritating problem and I am worried that the wall may have been weakened as a result of the hole that has been created.

Answer

When the new property was added on to the side of yours the developer would have been required to serve notice that they wished to make use of your wall and an appropriate amount of compensation should have been agreed. Once the property was built the area of wall that was enclosed became ‘party’ and the owners of the new property would have acquired rights over it. It is unlikely that they would have gained any rights over your chimney breast.   

Your neighbours would not have had a right to knock a hole in the party wall nor your chimney breast for the insertion of a decorative fireplace. It would be impossible to tell if the problems you are experiencing with you fire are related to your neighbour’s alteration without a thorough inspection. 

If the brickwork above the hole was not properly supported with a suitable lintel then it would have weakened the wall – an alteration to a structural wall would have required Building Regulation consent.  

Whether you can force you neighbours to block up the hole depends on a number questions – how long has it been there? Is it making the wall unsafe? etc but as they are not using it they are unlikely to object.

Follow-up

Thank you for your rapid reply. The house next door was I believe built in the 1920s or 30s and having looked at some photographs I suspect the hole into the party wall was put in at the same time, so I assume they got permission. I am not sure what action to take but I will give it further consideration.