PROJECT CELLAR CONVERSIONS

FAR LEFT, LEFT AND BELOW This listed house in Highbury, north London, had a dark and hard-to- access basementlevel kitchen and dining room. With a budget of £250,000, Appleton Weiner gained consent to alter the interior layout and build a side extension. (appletonweiner.co.uk)

Abiding by the rules

Converting an existing cellar or basement may be covered under permitted development (PD), in which case it won’t need planning permission. But consent will be needed in certain circumstances, such as when the conversion signals a change of use, or the addition of a lightwell alters the building’s appearance. Listed buildings and those in a greenbelt or conservation areas also need permission. ‘Basement conversions are often regarded positively in protected areas,’ says Ben Lee of Vita Architecture (vitaarchitecture.com). ‘But always check with your local authority, as some areas have removed PD to prevent further development.’

Seek guidance from your local planning authority in advance of any work. If you want to be certain that your proposal does not require planning permission, apply for a lawful development certificate (LDC). Visit the Planning Portal for further information (planningportal.co.uk).

The work needs to follow Building Regulations and the new space must comply with strict ventilation, access and dampproofing criteria. Terraced and semi-detached homes need a party wall agreement with any neighbouring properties affected by the work. ‘Search the surveyor database on the Royal Institute Of Chartered Surveyors website (rics.org) to find a local professional who can issue the correct notices,’ advises architect Stephen Butt of Lendel Stephens (lendelstephens.com).

‘Basement conversions are often regarded positively in protected areas, but always check with your local authority’

Construction matters

When there is insufficient headroom in the basement, the floor must be excavated to create more height. This can be a very slow process and involves structural work such as underpinning, which is where concrete reinforcements are inserted beneath the existing walls.

‘Underpinning provides support for the structure of the house while the floor is being dug out,’ says Robert Wood, director of Simply Basement (simplybasement.co.uk). If the ground floor above is retained, steelwork, new structural slabs or foundations may be needed. Whether or not they are required depends on the scale of the conversion, the age of the house and the existing foundations.

The spaces must also be protected from water ingress. This can be done in three ways: by creating a barrier, through structural integrity, or with a cavity drainage system that diverts water from the house. ‘A specialist waterproofing contractor can design and install the appropriate solution, but always seek an insurance-backed guarantee,’ says Stephen Butt.

For the project to meet Building Regulations, insulation, ventilation and heating will also need to be addressed.

RIGHT AND BELOW This five-bedroom Victorian townhouse in Primrose Hill, north London, has a utility room and kitchen-diner on the lower level. Architectural practice Zulufish increased the ceiling height to create a bright, open space that leads out to a secluded courtyard. The conversion costs took up £600,000 of the £1.2 million project budget. (zulufish.co.uk)

Is it affordable?

Budget from around £2,000 per sqm for the project. ‘Basement conversions are expensive, but in areas where property costs are high, bringing a cellar into use can be financially viable,’ says David Appleton of Appleton Weiner (appletonweiner.co.uk).

Excavation work can lead to an increase in costs. If you live in the middle of a terrace, digging beneath the building and transporting the soil and rock from the site is more challenging than with a detached house. This slows down the project – and more days on site will result in a higher bill.

Removing contaminated soil is also expensive. ‘Mixed waste or brownfill must be disposed of correctly,’ says Robert Wood. ‘To avoid unexpected expense, have a trial hole dug to determine the type of soil beneath your home.’

Ground investigations are crucial to avoiding other nasty surprises. ‘Sometimes manholes, soil pipes or inspection chambers must be moved or built around,’ Robert adds. ‘Costs vary depending on what needs to be relocated. Unless the ground is uncovered, or a CCTV survey carried out, it’s hard to gauge how much work is required.

‘Basement conversions are expensive, but in areas where property costs are high, bringing a cellar into use can be financially viable’

RIGHT, FAR RIGHT AND BELOW Both the lower ground floor and basement of this Victorian house were excavated to increase the ceiling height. EMR Architecture completely transformed the family home, which is in a conservation area of Chelsea, west London, at a cost of £1.5 million. (emrarchitecture.com)

PHOTOGR APHY ADAM SCOTT, LYNDON DOUGLAS

GOING IN AND OUT

Advice on staircases and means of escape from Rosie Caley, design director, OLBC Group (olbc.co.uk) ● Cellar staircases tend to be steep, with limited headroom. Building Regulations demand a 2m distance from the centre of each tread to the ceiling. As a result, it’s likely that your steps will need a longer run to get the required height. You may need to reconfigure your space at ground-floor level by removing a toilet or utility space, for example. ● If you’re short on space, having the basement staircase beneath the main flight above will save you room. ● Replicating the spindles and handrail style of the main staircase in the basement balustrade ensures a co-ordinated look. ● Glass balustrading allows light in and increases the sense of space. ● Building Regulations are very clear. You must protect against the threat of fire and smoke by providing either a secondary means of escape or a protected means of escape. The former is usually a staircase or ship’s ladder in a front lightwell, allowing you to get away from both the building and the grounds. Escaping to an enclosed garden is not sufficient. ● A protected means of escape entails fitting suppression devices such as misting systems or fire curtains. The latter are released from the ceiling to create a protective corridor. Either can be triggered by a smoke-detection system. ● When it comes to external access, lightwells often include steps up to the garden, which helps meet Building Regulations around access.

P I O N E E R I N G B R I LLI A N C E

Sheerline’s S1 roof lantern represents the next generation of aluminium designs

Having a good level of natural light in our homes can make us happier and boost our moods. This is one reason why homeowners throughout the UK choose to incorporate roof lanterns when extending or modernising their properties.

The S1 aluminium roof lantern from Sheerline is a pioneering design, with slim sightlines that let in the maximum amount of light. Yet it is also extremely secure. Its innovative design eliminates the security weaknesses found in traditional lanterns. Unique features such as anti-tamper screws, enclosed anti-tamper glazing, security tape and Sheerline’s patent-pending glass lock ensure there isn’t an easy way to enter your home. All these innovative features combine to make Sheerline’s S1 the UK’s most secure aluminium roof lantern*.

Made with UK-sourced aluminium, the S1 is manufactured in Derbyshire at Sheerline’s state-of-the-art facility. Its Thermlock technology delivers exceptional thermal performance. Closed-cell, insulating chambers work in conjunction with high-performance glazing to create class-leading thermal results that alleviate cold bridging problems. In addition, a unique coextruded perimeter ensures draughts and rain are kept out, insulating your home against the worst of the UK weather.

Slim 50mm sightlines ensure the maximum amount of light is allowed in, while from the outside, ultra-low line glazing bars create a refined architectural look. The S1 is available in a range of colours, with dual colours as standard, plus a bespoke colour service. LED light strips can also be installed to light up your room by night.

TOP A Sheerline S1 roof lantern helps to flood this kitchen with light, creating a calming interior space ABOVE Pictured in anthracite grey, the S1 features ultra-low line glazing bars for a sleek appearance

● To discover more about the S1 or explore Sheerline’s windows and doors, visit s h e e r l i n e . co m /b a l a n ce

Enjoy comfort for two on the Stella 2.5-seat sofa, from £3,309 in leather BELOW Go retro with the Metro high back recliner and stool, from £2,249 in leather

For the past 50 years the Stressless chair has been a byword for comfort. Launched in 1971, the globally renowned recliner has always adhered to the principle that form should follow function.

Comfort is king

With its patented systems, Stressless has developed the best resting positions for every part of the body. The Stressless Glide system makes it possible to shift seating positions using body weight alone. The Plus system adjusts to the correct head, neck and lumbar positions. These systems are cleverly hidden within the sleek design of the furniture.

A rich heritage

The company is rooted in the Scandinavian furniture tradition, featuring simple designs with leather and wooden accents. Each day 1,150 recliner chairs, 250 sofas and 300 dining chairs leave the Stressless factory in the small village of Ikornnes near Alesund on the Norwegian west coast. In the past decade the company has expanded its portfolio of products to include sofas, home office chairs and a dining range with the same emphasis on comfort. Beautiful and smart

Recently Stressless has designed and launched a range of powered recliner chairs and power sofas. Scott is an elegant-looking recliner with a multitude of functions available at the touch of a button via the control pad. The back and seat are slightly curved, and you can adjust the footrest, the tilt of the backrest and the neck support for the perfect seated position while you sink into the supple upholstery. In a first for the company, there are also additional heating and massage options.

Strong eco credentials

Sustainability is a value that is deeply ingrained in the company’s DNA. Its wood-treatment production line uses environmentally friendly products such as water-based stains and varnish. And in 2021 its Norwegian factory became completely powered by clean hydropower energy. The high quality of Stressless products means that customers are investing in furniture which is built to last, and which will have less environmental impact.

Honouring the past

In its 50th anniversary year Stressless is pairing the iconic base from the Original, its first chair from 1971, with modern models Metro, London and Tokyo. The base is a lightweight and elegantly curved steel design in a matt black or chrome finish, lending the result a distinctive retro look.

● For more information, visit st r e s s l e s s . co m