Basement Excavations
The defining local project. Digging below and close to neighbouring foundations almost always triggers the Act, usually with more than one notice.
Section 6Party Wall Services. Handled by Professional Surveyors.
Planning works on a Marylebone home, or just received a Party Wall Notice from a neighbour? LENIO Party Wall Surveyors handles the whole process for you.
Looking for a party wall surveyor in Marylebone? LENIO Party Wall Surveyors works across Marylebone Village, Dorset Square, Montagu Square and Baker Street, on both sides of the wall.
This is part of our Central London coverage, and a demanding party wall area of townhouses and mansion blocks. Most basements, underpinning and extensions here engage the Party Wall etc. Act 1996.
Most homeowners here ask this before a basement, underpinning or extension, usually when an architect or engineer raises it. Whether you need a notice depends on the works and how close they sit to your neighbour.
This guide sets out exactly which works are notifiable, how proximity to the boundary matters, and what to do if you are uncertain.
On these townhouses and mansion blocks, works usually affect a shared wall or dig close to a neighbour's foundations. That is why most projects are notifiable, and the party wall notice Marylebone projects require is the first formal step. Our guide on whether you need a Party Wall Notice covers it in full.
Marylebone is Central London at its grandest. Georgian townhouses and red-brick mansion blocks line the streets around Marylebone Village, Dorset Square and Montagu Square. Most homes are valuable and tightly packed.
With little room to extend outward, owners go down. Basements and underpinning are the defining projects, and both put real pressure on neighbouring foundations.
In the mansion blocks, cutting into a shared wall is notifiable, often with several owners to serve. That makes excavation and party structure work the central concern in Marylebone.
Most Marylebone projects engage the Act through one of four works. Each triggers a different notice.
The defining local project. Digging below and close to neighbouring foundations almost always triggers the Act, usually with more than one notice.
Section 6Strengthening an older townhouse's foundations is notifiable work to a party structure, especially where it adjoins a neighbour.
Section 2In a mansion block or townhouse, cutting into, thickening or altering a shared wall is notifiable work to a party structure.
Sections 2 & 3New foundations near the neighbour, or building to the boundary, bring the Act into play under the excavation and boundary provisions.
Sections 1 & 6The most common mistake we see in Marylebone is beginning the works once notice has been served, but before the Award is agreed. Owners treat the served notice as the green light.
It is not. If your neighbour dissents, or does not consent in writing, notifiable works cannot start until the Party Wall Award is settled and served. Serving notice is only the first step.
Starting before the Award is in place risks an injunction that halts the site. We move the Award along quickly, so the wait is short and the start date holds.
No matter what stage your project has reached, LENIO Party Wall Surveyors can take it on for Marylebone owners. The services below cover the process end to end, for both Building Owners and Adjoining Owners.
The first formal step for any Marylebone project: identifying which notice applies and serving it on every Adjoining Owner it needs to reach.
Explore Party Wall Notices →
A thorough photographic record of the neighbouring property, taken before work starts. It is the evidence both sides rely on if damage is ever alleged.
Explore Schedule of Condition →
If a neighbour dissents, we produce the Party Wall Award needed to move forward, setting out working hours, access, and the condition survey.
Explore Party Wall Awards →
Acting for the person carrying out the works, we serve the notices and manage the process so a Marylebone project runs to schedule.
Explore Building Owner Surveyor →
Acting for the neighbour who has been served, we safeguard their property and rights, usually with fees met by the Building Owner.
Explore Adjoining Owner Surveyor →
When both owners would rather appoint one surveyor than two, LENIO can act as that Agreed Surveyor, resolving matters faster after a dissent.
Explore Agreed Surveyor →Three terms Marylebone homeowners ask about most, and what each one actually means for your project.
A Party Wall Award is the document surveyors prepare when a neighbour dissents to your notice. It sets out how the works are carried out, the working hours, access arrangements and a Schedule of Condition. You only need one if your neighbour dissents, or does not respond within 14 days. If they consent in writing, the works proceed on the notice alone.
Many homeowners say party wall agreement when they mean either written consent or the Award that follows a dissent. A verbal yes gives no protection. If your neighbour consents in writing, that written consent is the agreement Marylebone owners rely on. If they dissent, the Award becomes the formal agreement that governs the works.
Before works begin, a party wall survey records the condition of the neighbouring property in photographs and notes. On these townhouses and mansion blocks, where the dig sits close to next door, that baseline is what settles any later question about damage. Both owners hold the same record, so neither side can argue about what the property looked like before the works.
A brief look at your drawings is usually all it takes to confirm whether a notice is needed, which one, the rough timescales, and the next step. LENIO Party Wall Surveyors gives that advice free of charge, and there is no obligation afterwards. For Marylebone, that usually starts with a look at how your basement excavations sits relative to the boundary.
A party wall surveyor Marylebone homeowners trust does more than send a letter. The job is to confirm which notices your project needs and serve them on every qualifying owner. It also means resolving any dispute so the works can begin on time.
LENIO Party Wall Surveyors is a specialist practice, led by a Chartered Civil Engineer and Member of the Institution of Civil Engineers (ICE). The lead surveyor is also a Chartered Building Engineer and Member of the Chartered Association of Building Engineers (CABE). On Marylebone basements, underpinning and mansion blocks, that mix of engineering and party wall knowledge is exactly what the job needs.
LENIO knows the local townhouses and mansion blocks well, and handles the process end to end. We keep your neighbour relationship calm while the works go ahead. LENIO is the party wall surveyor Marylebone homeowners call first.
Chartered Civil Engineer, Member of the ICE
Chartered Building Engineer, Member of the CABE
LENIO is based in central London and covers Marylebone and the wider Central London area in person. We attend for the party wall survey and the Schedule of Condition, so wherever your project sits in Marylebone, a chartered surveyor comes to you.
Call LENIO TodayA party wall matter is rarely about conflict. It is about doing the works properly while protecting the property next door, and keeping a neighbour you will see again on side. A specialist party wall surveyor in Marylebone handles it quietly and correctly, so the project does not stall. Here that most often means basement excavations, so it is usually the first thing we ask about.
The risks of getting it wrong are real. An invalid notice restarts the clock and delays the build. A missing Schedule of Condition leaves you exposed to a damage claim that is hard to defend, especially on older properties. A neighbour who feels ignored is far more likely to dissent.
LENIO Party Wall Surveyors leads with reassurance, not alarm. The first conversation is free, and a clear quote follows once the drawings have been reviewed.
Still working through a party wall question? These guides answer the most common ones in full. Start with the one closest to your situation, or explore the full library.
Which works are notifiable, how proximity to the boundary matters, and what to do if you are uncertain.
Explore The Guide →If your neighbour dissents, your project is not blocked. The surveyor route, the Award, and how long a dissent adds.
Explore The Guide →What each one is, when each applies, and how a notice can lead to an Award, so you know which applies to you.
Explore The Guide →The timeline stage by stage, what makes it longer or shorter, and how serving notice early keeps you on schedule.
Explore The Guide →Typical fee ranges for notices and Awards, who pays, and how to keep your party wall costs down.
Explore The Guide →What it includes, when you need one, what it costs, and how it protects both sides if damage is alleged.
Explore The Guide →Yes. LENIO works across the whole of Marylebone, from the Village and Marylebone High Street to Dorset Square, Montagu Square and Baker Street. If your street is not named on this page, a quick call confirms that we cover it.
We travel to you for the party wall survey and the Schedule of Condition, as part of our Central London coverage.
Not always. If your neighbour consents in writing, you can proceed. If they dissent, or do not respond, you must wait until the Party Wall Award is agreed and served.
Starting before the Award is in place risks an injunction. We move the Award along quickly so your start date holds.
Yes, almost always. A basement digs below and close to neighbouring foundations, which triggers the Act, usually under more than one notice. Basements are the most common notifiable work here.
Because basements carry real structural risk, the Award goes further than for a simpler job, and a surveyor who reads the structure is worth having.
Usually, yes. Underpinning that strengthens or adjoins a party wall is notifiable work to a party structure. It often sits alongside a basement on these older homes.
We confirm the position from your engineer's drawings and serve the right notice.
There is no single price, because the cost depends on how your neighbour responds and how many owners are involved. A consented notice sits at the low end, while a party wall award in Marylebone, after a dissent, costs more.
LENIO gives free initial advice and a clear quote after reviewing your drawings. You will know the cost before any work begins.
Whether you are the one planning the works or you have just received a notice from next door, LENIO Party Wall Surveyors operates across Marylebone and Central London. Reach out for free initial advice and a clear, project-specific quote. Basement Excavations is the project we see most often here, so we usually know the ground before we start.