Wall to Kitchen Extension became a Party Wall when Neighbours did the same. What to do Regarding Subsequent Damp Issues.

by: The Party Wall Surveyor


I built a wall on my land to create a kitchen conservatory extension. My neighbours then decided they would like to have something similar and I agreed to letting them use my wall and it becoming a party wall, and they paid me £1200 as a 50% contribution to the cost of the wall.
Now, 5 years later, the wall is damp and the new owners next door want to get it fixed (most of the damp is on his side, although there’s a tiny bit on mine). It seems that the glass roof was not put on at the correct angle and the guttering itself may not be wide enough.
The cost is potentially £8k to fix. This seemed excessive to me, and I said, let’s just try changing the gutter, to something wider, at a lot lower cost and see if that sorts out the damp before spending that sort of money.
He has appointed an MRICS surveyor and they want to know if I want to appoint a separate one to represent me.
And, thinking about how this has all come about it seems ‘fair’ that all of the costs to correct should, in fact, be his after all! Before the works by his predecessor, the wall was fine – then the work that they did caused the problem.
There was a Notice of Agreement to the side return extension, which I signed with the previous owner stating that ‘work… has been completed with no damage or consequence to your property’ and that going forward that we ‘will equally share future associated responsibility’. But clearly I could not have known that their builder had not completed the works in a satisfactory way, so as to cause damp at this later point. Your thoughts on whether he is likely to actually have to cover all of the costs would be appreciated.

Also, is his appointed surveyor really independent? Is there any recourse for me, should the surveyor not do an appropriate and professional job?


In order for your neighbour to have appointed a surveyor under the Party Wall Act he must have first served notice and you must have dissented to that notice – either by indicating your dissent in writing or by your failure to respond. If that has not been done then the surveyor is simply advising him. If he is simply being advised by a surveyor then it is up to the 2 of you to negotiate over who should pay the repair costs and you may want to employ a surveyor to help you with that.

If notice was served and you have dissented then you are deemed to be in dispute and surveyors must be appointed to settle that dispute in the form of a party wall award. From your description of the problem notice should have been served under section 2(2)(b) of the Act.

The Act allows for the 2 of you to appoint the same surveyor and any appointed surveyor is obliged to be impartial. While the fact that the surveyor is a member of the Royal Institution of Chartered Surveyors (MRICS) is reassuring it would be the fact that he was appointed under the Act that should ensure his impartiality.

Once surveyor(s) are appointed it would be his/their duty to determine responsibility for the defect and the costs should be apportioned to reflect that assessment, as set out in Section 11(5) of the Act (reproduced below).

Where work is carried out in exercise of the right mentioned in section 2(2)(b) the expenses shall be defrayed by the building owner and the adjoining owner in such proportion as has regard to—

(a) the use which the owners respectively make or may make of the structure or wall concerned; and

(b) responsibility for the defect or want of repair concerned, if more than one owner makes use of the structure or wall concerned.

The surveyor(s) decision will be set out in an award which is served on the 2 owners – either owner can appeal the award with 14 days but there would have to be a good reason to take that action.


In (b) below – ‘want of repair concerned’ – means if he wants the repair, but I don’t (as I don’t have the same need) – then just based on that element it would mean that he would bear a much higher proportion of the cost?


‘Want of repair’ in that context means ‘necessity for repair’ – in other words which owner caused, or allowed the defect to occur?