Buying Into Older North London Mansion Blocks: A Real Example of the Risks to Consider

Tollington Surveyors
6 days ago
4 min read

Buying Into Older North London Mansion Blocks: A Real Example of the Risks to Consider

We wanted to share another real example of the kind of situation we are seeing more often. Many buyers focus on the flat itself and the assumption that a simple internal refurbishment will be sufficient.

With older North London blocks, the wider building often carries the more significant risk.

In this example, the flat presented reasonably on inspection. This is typical of the 1920s and 1930s mansion blocks found across Highgate, Hampstead, Muswell Hill and Crouch End. These buildings remain highly sought after for their generous layouts, high ceilings, landscaped grounds, porterage and attractive Art Deco detailing. Original Crittall-style steel windows and characteristic façades add to the appeal. The location is excellent and the architecture distinctive.

Many buyers also assume that flats are easier to own than Victorian houses — particularly in Highgate, where Victorian properties are often smaller per sq m, more expensive to maintain and require a greater degree of individual responsibility. By contrast, flats can feel simpler: you pay a service charge and expect the building to be looked after. In reality, older mansion blocks often carry far greater long-term collective liabilities than people anticipate.

Underlying Risks in Older Blocks

However, with buildings of this age, the long-term liabilities sit within the structure and the communal areas rather than the individual flat. These blocks were constructed long before modern regulation and modern fire standards.Common findings include:

Flat entrance doors and communal doors that are not fire-rated
Service risers and cupboards lacking proper fire-stopping
Older electrical and heating risers that provide limited compartmentation
Unsealed service penetrations throughout communal areas

Fire Safety and Regulatory

Bringing a block of this scale up to a modern standard typically requires coordinated, building-wide upgrades, and these works can be substantial in both cost and disruption. Where a building has no reserve fund, no planned maintenance programme or inconsistent management, these works often arise suddenly, placing considerable financial pressure on leaseholders. This now intersects directly with the requirements of the Fire Safety Act, which place a legal duty on freeholders and managing agents to ensure:

Compliance of flat and communal entrance doors
Adequate fire-stopping to risers and penetrations
Safe and protected evacuation routes
Demonstrable management of fire-related risks

Practical Complexities

For older mansion blocks, achieving compliance is rarely straightforward. These buildings were never designed with modern fire separation in mind. Historically, compartmentation between floors is often poor, allowing smoke and fire to travel vertically more easily than current standards permit.

Many 1930s blocks also include dual-access service risers or utility cupboards opening into both communal hallways and individual flats. These typically house electrical meters, gas pipework, telecom cabling and heating distribution, and in their original form provide little fire resistance.

Electrical infrastructure adds another layer of difficulty. These buildings often have limited capacity for modern electrical loads. Running new cabling in a compliant and visually acceptable manner can be extremely challenging, requiring work to risers, historic finishes or surface-mounted containment. Concealing this work within the structure is often costly and complex.

Original Crittall windows, historic timber panelling, unsealed risers and outdated service cupboards cannot simply be patched. They often require intrusive works, coordinated access into flats and building-wide improvement programmes. Preserving the architectural character of an Art Deco block while carrying out such upgrades adds further complication.

Leasehold Challenges

Cooperation between leaseholders is essential, yet not always easy. Works may be delayed where:

• Leaseholders dispute the necessity or timing of upgrades• Payments are withheld or challenged• Access into flats is refused or delayed• The freeholder or managing agent fails to act promptly. In the meantime, the building may remain non-compliant, insurance premiums may rise and deterioration can continue. Marketability can also be affected, as mortgage approval may be restricted and a future buyer’s surveyor will flag the same issues.

Conservation and Planning Constraints

Externally, age-related deterioration should also be expected. Crittall windows often require full refurbishment or replacement. Flat roofs, balcony upstands, parapets, concrete elements and drainage systems may be reaching the end of their serviceable life. Without a reserve fund or structured maintenance programme, these costs often appear suddenly. Remember that most of these blocks in Highgate and Hampstead sit within Conservation Areas, and many are listed or locally listed, which adds further time, cost and complexity to any compliance or repair project.

Our Role as Local Surveyors

As local surveyors, we understand these buildings and know what to look for, based on years of inspecting similar blocks across North London. In this case, we advised the buyer clearly on the block’s wider risks, the scale of likely future works and the financial exposure that may follow. No survey can predict with certainty what a freeholder or managing agent will do in the future — those decisions sit outside the scope of a RICS pre-purchase inspection. Our role is to assess condition, highlight foreseeable risks and ensure buyers understand the likely implications before they commit. A clean, well-maintained property with proper management is often the more affordable and more stable choice in the long run.

Key Points to Consider

Fire safety compliance is often historic rather than modern
Service risers and unsealed penetrations can present major liabilities
Electrical capacity is frequently limited and upgrades can be expensive
Windows, roofs, balconies and drainage systems may be near end of life
Reserve funds are often inadequate, leading to sudden cost demands
Disagreement between leaseholders can delay essential works
Conservation Area and listing restrictions add time and cost
Non-compliant buildings face insurance, mortgage and marketability issues

If you are buying in North London and want clear, grounded advice, we would be pleased to help. At Tollington Surveyors, we are a genuinely local firm — based here, working here and familiar with the buildings, roads and communities that make this part of London so distinctive. We cover Highgate, Hampstead, Finsbury Park, Crouch End, Tottenham, Muswell Hill, Islington, Clissold Park, Haringey, Camden and the surrounding neighbourhoods. Our local knowledge means our guidance is relevant, practical and tailored to the homes we see every day.

Contact us today to arrange a RICS HomeBuyer or Building Survey — our process is straightforward, our advice is independent, and you will always deal directly with a qualified local surveyor.