A Guide to Loft Conversions

When you are considering an extension, the best way forward is probably to investigate the possibility of a loft conversion. Not only is this the most cost effective way of expanding your living space and add value to your property, but it will also obviate having to lose outside space for the building of a new extension.

Kennet Design are experts at making the most out of loft conversions. Our team of architectural planners know exactly how to maximise the available space and headroom, incorporate the features required for whatever purpose you have in mind for the loft room, and make sure your new room has plenty of light.

Once we’ve designed your loft extension to your satisfaction, we’re happy to recommend a tried and trusted contractor and put our project management team to work on your behalf, to see the build through to the end.

You’ll probably have plenty of questions to ask when considering a loft conversion, so we’ve tried to anticipate these and put together this basic guide to loft conversions:


Generally not, unless you live in a listed building or conservation area. Loft Conversions are usually deemed “Permitted Development” because they do not change the existing footprint of the building.

When we draw up plans for a loft conversion we check with the local planning office on the permissions required.

We also provide technical drawings for the Local Authority building inspectors.


Things to take into account are the height of the loft space and the pitch of the roof. There are structural considerations too and things like water tanks or chimneys have to be taken into account.

The Building Regulations don’t impose a minimum ceiling height for habitable rooms, but a room without sufficient headroom would be awkward, and there are regulations about the amount of headroom at the top of stairs. Generally you need to have at least 2.3m available at the highest pitch point of the loft to accommodate a conversion.

The higher the pitch angle of the roof the more height you’ll have. If the pitch doesn’t leave much room to manoeuvre, dormer windows can always be added.

A structural engineer will need to assess the form of roof construction used in your roof, to make sure it is strong enough or perhaps needs added support to accommodate a conversion.

If your loft does not immediately appear suitable for conversion, all is not lost. Kennet Design has various solutions available that make it possible to plan a conversion of almost any loft space, for example altering the roof itself or dropping the ceiling of the room below.

If in doubt, contact us for a consultation and we’ll happily talk you through our suggestions.


There is no definitive answer to this question, because there are so many variables involved such as whether there will need to be changes to the roof structure, dormer windows installed and the kind of insulation used.

When Kennet Design plans your bespoke loft conversion, you will be given detailed specifications to source quotations from a contractor before deciding to proceed with the build.

Roughly you can expect a very basic loft conversion to cost between £15,000 and £20,000.


If you’re converting a loft to add a bedroom, it’s a good idea to put in an en suite bathroom too. Fitting in a bathroom (or preferably, to save space, a shower, toilet and basin) is down to good planning and design. A shower needs full head height and the position of the existing waste water and supply pipes in the house need to be considered.

Our experienced design team at Kennet Design are able to site an en suite correctly in a loft space so as to simplify the plumbing required for successful operation, saving money on the build, and ensuring there is adequate ventilation to prevent condensation.

More questions? We’ll be very happy to answer them! If you’re considering a loft conversion contact Kennet Design for a no-obligation consultation at your convenience.


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Areas covered: Wiltshire, Oxfordshire, Bath, Bristol, Avon & Somerset, Dorset & Gloucestershire
Phone : 0345 548 0000
Email : info@kennetdesign.co.uk
Address : 4 Scotchel Green, Pewsey, Wiltshire SN9 5AU


Areas covered: Oxfordshire, Berkshire, Buckinghamshire, Gloucestershire
Phone: 0345 548 0000
Email: info@kennetdesign.co.uk
Address: 41 Hendred Street, Oxford OX4 2EE


Areas covered: Hampshire, Berkshire, Surrey, East & West Sussex
Phone : 0345 548 0000
Email : info@kennetdesign.co.uk
Address : Landmark House, Station Road, Hook, Hampshire RG27 9HA