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Renovating a Period Mansion Block: Everything You Need to Know

A substantial portion of Central London property is made up of mansion blocks. These pose specific challenges and requirements along with the expected idiosyncrasies of a period property. Huntsmore have completed a number of projects in these buildings; below are our insights.

Licence to Alter

A license to alter is permission from the Landlord for the leaseholder to make alterations to their property. Check your lease for clauses dealing with the situation where you want to make alterations to your flat.

Typically works which require a license to alter are:

  • altering the structure
  • installing or moving sanitary ware items
  • new heating and service installations
  • breaking through an external wall
  • removing any wall (solid or partition)
  • changing windows
  • scaffolding and significant rewiring/plumbing.
  • Please note this list is not exhaustive, and influenced by the lease criteria*

Applications can be comprehensive, often taking 6-8 weeks for approval from submission, and usually need the following information:

  • description and program of the works
  • drawings showing existing and proposed layouts
  • structural drawings and calculations
  • building services drawings
  • specifications
  • risk assessments and method statements
  • asbestos survey
  • a copy of your F10
  • evidence of insurance
  • evidence of necessary planning, building regulation permissions, any other statutory approvals and proof of compliance with the Party Wall Act

Not completing and complying with the license to alter can lead to enforcement action. Or difficulties in selling your property if you have unregulated changes and may be complicated and costly to seek retrospective consent.

Consider mansion block’s access point

Most mansion blocks have designated access points; the accessibility of these varies from site to site. Some are on double yellow lines on a busy main road and others have allocated parking. Access setup, distance and route to your flat will have a demonstrable impact on the planning of your project. Timing of deliveries will need thought; do the items fit in the lift or stairwell? (maybe you need a crane). Extra time will need accounting if it’s a convoluted, and slow route from the access point to your flat.

Consider the logistics and parking

A lottery at the best of times, many flats have parking allocated and some none at all. Vehicle size might be restricted as underground car parks have height limits. There will not be enough parking for everyone accessing site, so alternatives will need arranging.

Keeping your neighbours informed

Whether you’ve just moved in, or a long term tenant, you want positive relations with your neighbours. Most people are understanding, and the key to keeping them onside is communication and diplomacy. Our approach is to treat others as we’d like to be. We always write a letter before the project starts and keep tenants informed. Disruptive and noisy works are communicated well in advance and organised to minimise the impact.

Do you need to alter the main services?

Any alterations to main supplies (water, gas, electric, data, waste) which are outside your demise or form part of the shared infrastructure will most likely need coordinating with the Landlord. For example; older buildings may have communal heating systems which need fully draining before work commences. Or any changes needed to the electricity mains head would need organising by the Landlord with the supplier.

Party Wall Agreement

A party wall is a shared wall between two properties and governed by the Party Wall etc, Act 1996. ‘An Act to make provision in respect of party walls, and excavation and construction in proximity to certain buildings or structures; and for connected purposes’. It seeks to protect the interest of adjoining owners from adverse works and provides a mandatory dispute resolution procedure.

There are several scenarios which require a party wall agreement. Within a mansion block, these would generally be works on party structures; such as party walls, floor and partitions. On the ground floor this would also apply to a fence line should you have a garden. You don’t need to inform your neighbour about minor changes, e.g. plastering, adding or replacing electrical wiring or sockets, or drilling to put up shelves or cabinets.

You must give your neighbour notice between two months and a year before buildings work to start.

The agreement usually includes:

  • The party wall award: guidelines governing how the works should progress.
  • A schedule of condition of the adjacent property, possibly with photos.
  • Drawings and details of the proposed works.
  • Details of the contractor’s public liability insurance.
  • Neighbour’s surveyor’s fee.
  • Indemnities by the building owner in favour of the neighbour.
  • Both addresses.
  • Surveyors’ details and access arrangements for them.
  • Working hours and the time limit for work starting (usually one year).

If an agreement is not reached, you’ll need to appoint a surveyor to arrange a Party Wall Award. With luck your neighbour will use the same surveyor – an ‘agreed surveyor’ and only incur a single set of fees. Or, your neighbour can appoint their own surveyor at your expense.

Remember that each boundary your completing works requires an agreement with the relevant neighbour. While failing to follow the act is not an offence; your neighbours can take civil action and issue an injunction. This will create project delays and is likely to increase costs. The builder may demand compensation or move to another project. Neighbours may seek compensation if a loss is suffered as a result of the work and could result in removal of the work. This also applies if you have a party wall agreement with your neighbours but do not observe the terms agreed.

Communal Areas

Communal areas are shared spaces such as lifts and corridors. As you would expect, these need to be protected and repaired should damage occur. If left damaged, the Landlord could charge for repairs. A Dilapidation Survey might be needed, which establishes a condition date baseline. The subsequent survey will provide a detailed report of the works required to restore the property to its original condition.

Working hours & Rubbish removal

These vary dramatically from block to block. Almost all have working hours from nine to five, Monday to Friday. However, some impose specific measures such as noisy works from ten to twelve and two to four or maybe a one-hour lunch break for all activity. Project planning will need to allow for these nuances. For example, if noisy hours are limited to four, this will reduce activity; that time would be for maximum output of noisy work and the rest for clearing/quiet work. You’d also have to plan rubbish clearance and deliveries around these times. Whatever the rules, you must obey or run the risk of being thrown off the site.


If scaffolding is needed for internal work, as highlighted in the sections above, careful planning will be needed to gain access and install. The scaffolding plan should be included in the license to alter program of works. If scaffolding is needed externally, permission will be required from the freeholder, should the structure land on the pavement or road outside your property your builder or scaffolder must get a licence from your local council. It is up to them to obtain the licence, but it is your responsibility to check that they have the appropriate paperwork.

Sanitary Ware

Testing of mains water pressure, at peak usage time (i.e. mornings when people are getting ready for the day) might be required to determine the specification of sanitary ware items. This is important as some shower heads for example require high levels of water pressure, if you test during the day the pressure might be OK, however at peak times the pressure will drop due to the increased demand for water and the shower head might not be compatible.

Are you looking to renovate your period property?

The best policy is prudence, to always check your lease, discuss works with your freeholder and be sensitive to neighbours before embarking on a project. Engaging an experienced client-side project manager like Huntsmore would relieve you of the hassle whilst saving time and money. If you have a specific project in mind, we invite you to book a complimentary consultation with one of our experienced renovation experts who will advise you on how to turn your ideas into reality.