27 Jul 2016

Considerations for your loft conversion


A loft conversion can offer an extra bedroom, bathroom or a home office. However, there could be height and access issues alongside planning and Building Regulations that need resolving. Even so, a loft conversion can be life changing and a cost-effective solution to moving. Here, Ian Harvey, Director of Harvey Norman Architects, offers a brief overview of what to examine when considering a loft conversion.


• Internal: The most cost-effective solution that involves little alteration i.e. windows in the existing roof slope, insulation and floor strengthening.

• Dormers: These are added to increase volume of the space, while providing full head height.

• Roof off: This is a complete new build structure, and it is the most expensive solution.

Will it work?

• Access: The position of the loft staircase is everything.

• Head height: The minimum is 2.2m (7.5ft). Lowering the downstairs ceiling can give more headroom, but the additional costs may outweigh the benefits.

• Structure: Cut roof will be straightforward. However, post-1960s homes were built using ‘W’ trusses, which converting can be complicated.


Permitted development laws have made it easier, so very often you shouldn’t need planning permission. You must however, comply with Building Regulations.

Fire safety is a crucial – the loft storey must be protected by half an hour’s worth of fire resistance from the house, which means fire doors. Escape must be via a protected corridor and stairs can’t lead straight down into an open-plan area.

Lastly, if any work affects the wall and floor or ceiling of the adjoining property, a party wall notice will be needed.


Since every house and conversion is different, alongside the type, it’s hard to generalise on costs. However, I would recommend keeping an eye on the price guides in most magazines.


Split level conversion on Muswell Hill:

This £34,000 Econoloft loft conversion on an Edwardian property in London’s Muswell Hill took advantage of the fact the property is built on a slope with the front higher than the back. Econoloft developed a split level room comprising a sleeping area at the top and a study-cum-sitting room area at the bottom, where natural light floods in through two sash windows, in-keeping with the rest of the house. The conversion also features an en-suite shower room and a nifty storage area with clothes rails and shelves.


The double dormer:

Here, Simply Loft has provided an expansive loft conversion creating two new double bedrooms, each with an en-suite bathroom. Acurate use of the apex roof allowed Simply Loft to also incorporate a snug screening room on the client’s request. A bank of four skylights bathe the snug area in natural light while rows of spotlights, embedded into the floor panels, illuminate the space at night.


Bright and spacious

Converting a loft is one of the easiest ways to increase floor space in a property. However, one of the main challenges of a loft conversion is ensuring it looks spacious, light and bright. Here, VELUX offers some top-tips for brightening up a loft space with windows.

Top-hung roof windows are perfect for lofts, where low, sloping ceilings can make a room appear smaller and darker. Installing roof windows, particularly ones that are top-hung operated, can dramatically increase the flow of daylight into the loft space and really brighten the room.

For example, VELUX top-hung roof windows can be installed on a roof pitch of between 15 and 55° and open to a 45° angle, allowing for the maximum flow of fresh air into a property. These windows open outwards offering more headroom and uninterrupted views.

To increase the brightness within your loft for a more modern living space, VELUX recommends a white painted finish. This allows for even more light to be reflected into the loft you’re converting and is a perfect match to a contemporary interior.



Phil Rigby, Product Manager at Knauf Insulation, explains what to consider when installing insulation in roofs at ceiling level.

It is possible to achieve very high levels of insulation in pitched roofs, where the insulation is positioned at ceiling level, as the thickness is largely unrestricted by construction considerations.

When insulation is installed in roofs at ceiling level, there is a risk that condensation will form on the cold side of the insulation in the loft space. Condensation is most likely to occur when warm, moisture-laden air (water vapour) is able to pass through to the cold loft space, but is prevented from dissipating to the atmosphere by the roof structure.

There are a couple of key steps that can be taken to prevent condensation:

• Restrict the passage of warm air and water vapour by ensuring that the ceiling is well sealed.

• Ensure the loft space is sufficiently well ventilated at the eaves or roof ridge to allow water vapour to disperse through its structure and dispel into the atmosphere.

Once one of the above factors, or both, has been completed, the first bottom layer of loft roll, such as Earthwool loft roll, should be laid tightly in between and to the same depth of the ceiling joists (usually 100mm) and overlaid at right angles with a thicker top layer or layers, with all edges tightly butted. This helps to minimise thermal bridging through the ceiling joists and guarantees compliance with Building Regulations.


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