Party Wall Agreement for a Loft Conversion: Notice and Costs

When a loft conversion needs a party wall agreement

The Party Wall etc. Act 1996 lets an owner cut into a party wall to take the bearing of a beam, and GOV.UK’s explanatory booklet gives a loft conversion as the example. GOV.UK’s guidance lists the kinds of work the Act covers.

• Building a new wall on or at the boundary
• Cutting into a party wall
• Making a party wall taller, shorter or deeper
• Removing chimney breasts from a party wall
• Knocking down and rebuilding a party wall
• Digging below the foundation level of a neighbour’s property

The Act is separate from planning and building regulations control, GOV.UK’s booklet says, so having planning permission for the conversion or building regulations approval does not remove the need to go through the Act’s procedures with your neighbour.

Party wall notice periods for a loft conversion

Notice of work on an existing party wall goes to your neighbour at least two months before the planned start date, GOV.UK’s booklet says. Building a new wall at the boundary, or excavating, needs at least one month’s notice.

From the notice to the party wall award, the formal document surveyors draw up when there is a dispute, the booklet sets these steps for work on an existing party wall.

Step	When	What happens
Notice served	At least two months before the planned start	Your neighbour is told about the work to the party wall
Your neighbour replies	Within 14 days	They consent in writing, refuse or do nothing
Dispute deemed	14 days after the notice is served, if they have done nothing	The dispute procedure applies
Surveyors appointed	Once a dispute arises	One agreed surveyor, or a surveyor each
Third surveyor	If the two surveyors cannot agree	The third surveyor, selected by the two, is called in
Award made	When the surveyors settle the matter	The award sets out the work and when and how it is carried out

What your neighbour can do with the notice

A neighbour who receives the notice can give consent in writing, refuse to consent, or do nothing, GOV.UK’s booklet says. If they have done nothing 14 days after the notice is served, a dispute is deemed to have arisen.

If your neighbour consents and no dispute arises, the Act does not require you to appoint a surveyor, the booklet says. Consent does not remove your duties under the Act, such as avoiding unnecessary inconvenience and providing temporary protection for the neighbouring property where necessary, and a difference that comes up later, over damage for example, goes to the dispute procedure.

When you first raise the notice with your neighbour, give them the facts the Act turns on: the work to the wall, the start date, the 14 days and what happens if they do not agree.

Party wall surveyors when your neighbour does not agree

If there is a dispute, you and your neighbour can agree on one surveyor, which the Act calls an agreed surveyor, or each appoint a surveyor, GOV.UK’s booklet says. The two appointed surveyors select a third, who is called in if they cannot agree. A party wall surveyor acts impartially, even when one surveyor serves both owners, Checkatrade says.

The booklet says the award sets out the work, when and how it is carried out, any additional work such as protection against damage, and access for the surveyors to inspect the work, and it often records the condition of your neighbour’s property before work begins.

Party wall surveyor cost for a loft conversion

Checkatrade’s loft conversion cost guide lists party wall agreements among the hidden costs of a loft conversion, alongside architect drawings at £1,000 to £2,000 and structural engineer calculations.

A party wall surveyor for a loft conversion costs £1,575 on average, on Checkatrade’s party wall surveyor figures. Checkatrade puts a party wall award at £1,000 on average and a surveyor’s hourly rate at £200 on average, in a range of £90 to £450, with the fee depending on the time the work takes.

One agreed surveyor or a surveyor each

For a loft conversion, Checkatrade’s figures put one agreed surveyor at half the cost of a surveyor each, and a third surveyor, if the two cannot agree, can push the total higher still.

Route	One agreed surveyor	A surveyor each
Who appoints	You and your neighbour agree on one	You and your neighbour appoint one each
Cost for a loft conversion	£900 to £1,200	£1,800 to £2,400
Who draws up the award	The agreed surveyor	The two surveyors together

Usually the building owner pays all the costs of drawing up the award, including the neighbour’s surveyor’s fees, if the work is solely for the building owner’s benefit, GOV.UK’s booklet says. So if the conversion is solely for your benefit and your neighbour appoints their own surveyor, budget for both fees.

What the surveyor’s fee depends on

Besides the number of surveyors, Checkatrade says the fee depends on the size of the property, the quality and completeness of the architectural designs, how complex the work is, such as whether a structural engineer is needed, the risk of damage to your neighbour’s property and the negotiation involved. Among the Nottingham loft conversion companies we rank, Roof Rooms supplies full working plans and structural calculations.