Is Leak Caused by my Neighbour’s Works

by The Party Wall Surveyor


My neighbour recently undertook some works and at about the same time I noticed a leak to my conservatory roof. I cannot find where the water is coming in from but it’s too much of a coincidence for it not to be related to the works. Is it my neighbour’s responsibility to investigate? He doesn’t seem to think so.  


If you believe the leak to be related to party wall works (I should stress that is the work covered by the Party Wall Act rather than the general works) and your neighbour is denying responsibility you have the option to refer the matter to the appointed surveyors for determination. The risk with this course of action is that the surveyors determine that there is no link and that you not only end up paying to make good the damage caused by the leak but also the surveyors’ fees. 

Referring a dispute to surveyors can be time-consuming so the priority should be to resolve the leak thereby removing the risk of further damage and mitigating your losses. With that in mind, I would suggest organising the repair yourself but recommend that you ask the contractor to write a brief report providing their opinion on the cause (and take photos if inaccessible). This needn’t be anything comprehensive, just a couple of lines written on the invoice. 

The contractor’s opinion will help you decide whether the defect is actually related to the party wall works and, if so, will be an important piece of evidence that should be passed to the surveyors (it may even encourage the building owner to accept responsibility and avoid the need for surveyors’ involvement at all).

Calculating a Loss When a Crack Widens

by The Party Wall Surveyor


I consented to my neighbour’s works on the understanding that I should not suffer as a consequence. Many of the existing cracks have widened but my neighbour is saying because they are existing they are not his responsibility. Can this be correct?


Certain rights under the Act, such as cutting in to a party wall, come with an obligation to make good damage, while others, such as excavating close to a neighbour’s property do not. However, the building owner (the party undertaking the works) is responsible for any loss or damage caused by their works. The distinction may appear technical but it’s relevant to your query. 

If a crack has widened as a result of the works it is unquestionably damage and as such the building owner has a duty to make good. Importantly, it also follows that you, as an adjoining owner, can elect to receive a payment in lieu of making good (see section 11(8) of the Act). 

If there is no duty on the building owner to make good they will only be responsible for the loss suffered as a result of the works. The ‘loss’ when an existing crack widens slightly is always difficult to assess – it does not cost any more to make it good so the more relevant point is whether, as a result of the crack widening, it has become more urgent to make it good and redecorate. 


My neighbours are extending in to their basement. Recently the drilling work has intensified and I’ve noticed a crack in the hallway. Should they be using a lower level of force in the drilling i.e. so the house is not shaking and creating cracks as they go?


You don’t say whether there is a party wall award in place but if there is the appointed surveyor(s) should have considered ways in which they could reduce the risk of damage. A typical safeguard would be to prohibit the use of percussive tools (such as hammer drills, kangos etc.) on works directly affecting the party wall. Vibration can carry from works on other parts of the property, over which the party wall surveyors have no control, to the party wall and cause vibration but that would be less intense than work directly to the party wall.

Even if you consented to the works and there’s no party wall award you may want to suggest this safeguard – it is in the building owner’s interest to avoid damage.

The Act gives you the option of either allowing the building owner (or their contractor) to make good the damage or receiving a payment in lieu. This applies whether or not there is a party wall award and if there is a dispute relating to that damage you have the right to appoint a surveyor.  If the heavy work is ongoing it may be best to deal with this later in case there is further damage.

If there is a party wall award in place which prohibits the use of percussive tools but it is being ignored it is more a matter of enforcement – I would suggest that you raise it via your appointed surveyor in the first instance but if that doesn’t work the only remedy is an injunction (although I would recommend you seek legal advice before going down that route).

Shared Chimneys in a State of Disrepair

by The Party Wall Surveyor


I have been reading your article on repairing/removing shared chimney stacks on your website which has been very helpful.  You mention that a Party Wall Notice is not required when removing a chimney, but is required for the remedial work when removing part of the shared chimney. Is a Party Wall Notice required when rebuilding the head of a chimney, and repairing the mid feathers? (There are a few courses in the mid feather missing, and some remaining bricks overhanging.) 


The same principle applies to both parts of your question – the repair works are only be notifiable under the Act if they affect the wall dividing your flues from your neighbour’s flues. If you wanted to rebuild the whole of the head that could only be done in agreement with your neighbour. Looking at the condition of the head of the stack, re-building it jointly with your neighbour would be the best option.


Just so I know, what exactly does the party wall award grant that is different from the schedule of condition and our assurance that if our work caused any new issues then we would rectify it? 


A schedule of condition is a written record (usually supported by photographs) of the parts of an adjoining property that are likely to be impacted upon should anything go wrong with a building owner’s works.  It can be referred back either during or following the works should there be a claim for damages against the building owner (in a similar way to how a dilapidations claim is assessed on a commercial property). 

A party wall award is the document that is produced by appointed surveyors to resolve a dispute between owners where there has been a dissent to the party wall notice(s). An award will generally include a schedule of condition which may be why the two things are sometimes confused. 

Where an adjoining owner consents to a party wall notice they will sometimes do so on condition that the building owner pays a surveyor to schedule the condition of their property. The building owner will generally be happy with such a response as the costs of having one surveyor record a schedule of condition is considerably less that two surveyors agreeing an award.  

This article gives a succinct overview of party wall procedures.


We are planning to serve notices on the adjoining owners.  However, on the Land registry website the recorded owner of the property has passed away and detail of ownership has not been updated.  Who should we address and send the appropriate notices to?  Who will therefore act on the adjoining owner’s behalf in order to respond to the notices?


Where there is uncertainty over the ownership of an adjoining property it would be best to address the notices to ‘The Owner(s)’ in accordance with section 15 of the Act.  Do bear in mind that notices addressed to ‘The Owner(s)’ must be either handed to a person on the premises or fixed to a conspicuous part of the premises. You can read more about the methods of service here.


At the rear of two buildings there is a very old boundary wall which acts as a party wall and is shared between the two buildings.  There are no records of where the boundary lies so we assume it runs down the middle of this wall.

On one side of this wall, there is Neighbour One’s garden.  On the other side of the wall, there is a single storey storeroom created in the 1960s by roofing over the garden of Neighbour Two.  So the storeroom belongs to Neighbour Two.  There is probably some tanking or a void between the storeroom and the boundary wall, but the boundary wall does support the roof of the storeroom.

Thus, it will be noted that the shared boundary wall has to be used for two purposes – to act as a garden wall for Neighbour One and to act as part of a flat-roofed building for Neighbour Two. The only access to this wall is through Neighbour One’s garden.  There is no opening from the storeroom into Neighbour One’s garden – the wall is blank.

If the two neighbours differ in their view as to how to maintain the wall, how could this be resolved, preferably without recourse to party wall surveyors and serving formal notices?  And does the Access to Neighbouring Land Act apply here, even though the boundary wall is agreed to be a shared party wall and Neighbour Two cannot prove or claim full ownership?


Original walls dividing rear gardens will tend to be built equally astride the boundary and if both neighbours agree it’s probably best to proceed on the basis that it is a party fence wall.

If the wall is defective or in want of repair, one of the parties will need to take the lead (they would become known as the ‘building owner’) and serve a Party Structure Notice. The notice should set out what is proposed and how they think the costs should be apportioned. If the recipient of the notice (known as the ‘adjoining owner’) agrees with what is proposed they should consent to the notices and pay their contribution when presented with an invoice upon completion of the works.

If the adjoining owner does not agree with what is proposed they they can dissent to the notice and trigger a dispute – both owners would then have to appoint surveyors (or a single surveyor) to determine that dispute. Section 11(5) of the Act sets out how the costs of the works should be defrayed between the owners i.e. according to the use which the owners respectively make of the wall concerned and responsibility for the defect or want of repair concerned.



My neighbours have permission not only to build onto, but also to increase the height of, the wall at the end of my garden.  Neither their builder or surveyor was aware that the level of our garden is higher than the plot and that the walls they are building onto will be effectively below ground or that they also bordered another garden.  I have no building experience and so I am not sure whether their construction method is correct.  Do I just have to accept their opinion that the wall will be fine with more weight added and holes dug nearby?  2 years ago the adjoining garden wall collapsed – it had no foundations.  It was ridiculously expensive and disruptive.  Can I ask to see who has insurance in case someone makes a mistake?   

The surveyor has emailed to say a Party Wall Notice is coming in the post and done some updated plans.  I think we need advice about the Party Wall Notice but also the boundary generally.  If we enter into a Party Wall Agreement are we conceding that we do not own the wall without any further investigation? 

Finally over the summer the owner was with the surveyor as I passed and they mentioned that they would like access to my garden to erect scaffolding.  I asked at the time and subsequently in writing that they let me have details in good time for me to consider but I have no further information.  Were we to agree to scaffolding I guess we would need an agreement in place for that.

Were we to instruct a surveyor would we be responsible for fees relating to advice on construction method etc?


Assuming that the wall at the end of the garden is built astride the boundary it will be a party fence wall. That being the case, any works that directly affect that wall or any adjacent excavation will be notifiable to you under the Party Wall Act. Upon receipt of those notices you will have the right to dissent and appoint a surveyor of your choice and, in all normal circumstances, that surveyor’s reasonable fee will be paid by the building owner (being the party benefiting from the works). The building owner will also need to appoint a surveyor although you can both concur in the appointment of a single surveyor (known as the ‘Agreed Surveyor’).

Section 2(2)(a) of the Act confirms an owner’s right to increase the height of a party fence wall so you can’t prevent the building owners from doing that.  However, the appointed surveyor(s) will determine the time and manner of executing any work and that would include the method of construction insofar as it effects the party fence wall. 

If there are significant engineering issues to be agreed, such as the design of a retaining wall, your surveyor can argue that he/requires input from an advising engineer (at the expense of the building owner) and that would normally be considered reasonable.

The Act provides a right of access where it is necessary to undertake notified works and where that is the case the details will be agreed by the surveyor(s) and confirmed in the document that they serve on the owners (known as a ‘party wall award’)

Insurance is not a matter for the appointed surveyors but the building owner is responsible for any damage caused by the notified works and you have the right to request security for expenses.

Party wall surveyors do not determine boundaries but nothing that they agree will affect the current status of the wall.    


Our neighbours have served a notice on us stating their intention to build a kitchen extension up to the boundary line between our properties. Within our side of the boundary is a brick garden wall about 12ft long, the rest being wooden fencing, which lies on the boundary along the remaining  length of the garden.  On our side of the wall and fence is an established border with mature plants and fruit trees.  Our neighbour informs us that the brick wall will have to be demolished, the wooden fence taken down, and the border removed and paved as we would not be allowed to breach the new damp proof course to his extension.

We just want to know whether (a) he has the right to destroy our brick wall, and (b) has the right to tell us that we can no longer have a planted border as it would breach his damp proof course?  We don’t really object to the extension, but we do object to our garden being destroyed. 


If the wall is on your land (as you say below) your neighbours do not have the right to remove it. The Party Wall Act gives them the right to underpin it if that is necessary to keep it stable during the works. 

If your wall remains the question in respect of bridging the damp-proof course does not arise.   

If you allowed your wall to be removed (to be neighbourly) that would be as part of an overall agreement to reinstate your planter in a way that did not bridge the damp-proof course e.g. with a low level wall to the rear of the planter and either a gap or some gravel fill behind that. All of the necessary work, including incidental costs such as potting up and reinstating plants as necessary, would be at your neighbours’ expense. The exact details would be agreed either between the owners or the appointed surveyor(s) should you choose to dissent to the notice.


We are planning to repoint the wall in our cellar/basement using lime mortar as the current cement pointing seems to be having a corrosive effect. 

In this case do you think we need a formal Party Wall agreement? 


I think what you’re asking is ‘do we need to serve notice’? A party wall agreement is only required if the notice is dissented to

The Act includes general descriptions of the type of work that is covered but unfortunately does not cite examples. The clause that potentially covers re-pointing a party wall is found in section 2(2)(f): 

to cut into a party structure for any purpose (which may be or include the purpose of inserting a damp proof course); 

The Government Explanatory Booklet to the Act (page 13) gives some examples of work that might be considered too minor to be notifiable including ‘cutting into a party wall to add or replace recessed electric wiring and sockets’ which to me poses a greater risk of damage than re-pointing. 

So, in summary, I don’t think re-pointing is notifiable but that is just an opinion and other surveyors may disagree.