Adding an extra bedroom is a reliable way to increase the value of your home – from converting a loft to building a garden room. 

OBA Elmsdown garage conversion into bedroom

Image: Garage conversion project by OB Architecture. Photography: Martin Gardner

Whether you've got a new arrival in the family to make room for, or you're just looking for space for guests to stay in when they visit, an extra bedroom can completely change how your home functions. 

If you're considering re-configuring your home's layout or extending to create another bedroom, the good news is that it will likely pay dividends when it comes to increasing the value of your property. 

Recent research from Safestore shows that the addition of an extra bedroom can have varied effects depending on your location in the UK. For example, in Manchester, increasing from a 1 bedroom to a 2 bedroom will increase value by 13%, while between 3 and 4 bedroom, the value increases by 67%; yet in Cardiff the difference between a 1 bedroom and 2 bedroom house is nearly 50%. 

Consult your local estate agent and you'll soon have an idea of the budget you have to play around with in order to recoup your cost outlays. 

Loft conversion 

Browning Architects quarry road loft extension - grand designs

Image: A flat-roofed design for this loft allowed for a ‘floating’ opening with wall-to-wall glazing. Designed by Browning Architects, it cost £3,500 per sqm. 

Loft conversions can be pretty straightforward projects and yield one of the best returns on investment when it comes to adding an extra bedroom.

Expect to pay £20,000+ for a good-quality conversion depending on size and where you live, but with lots of companies doing them, prices are competitive. Many lofts can be converted under permitted development, but rules apply, especially if it alters the appearance of the exterior of the property. If you’re attached to a neighbouring property, then you’ll need to issue a party wall notice to its owners.

Other key considerations include head height of the loft, as you'll need to achieve around 2.3 metres to make a conversion space work, and you'll also need to consider where the access staircase will sit on the lower floor. 

Elmwood Road conibere phillips roof extension - grand designs

Image: Re-working a building previously divided into flats to create a family home, Conibere Phillips Architects added a roof extension, creating space for an extra bedroom elsewhere in the house. The architects also united it with the neighbours' existing extension to create one striking timber clad structure. 

If you don't have the space for a loft conversion, why not consider a roof extension? These are more costly, and will require planning permission.

Other key considerations that rule whether a loft extension is on the cards include head height of the loft, as you'll need to achieve around 2.3 metres to make a conversion space work, and where the access staircase will sit on the lower floor.

Use the garage

OBA Elmsdown garage conversion into bedroom - grand designs

Image: OB Architecture rebuilt the garage of this home to add in a bedroom, moving its facade forward to give more floor space and installing a dormer window. 

Garages are often single-skin brickwork, and will need to be brought up to spec to comply with building regulations. This will involve insulating the walls and roof, but also the floor, as the bedroom will be located above an unheated room. 

A simple addition above the garage will likely cost in the region of £1,000 per sqm.

A garage conversion may fall under permitted development, so long as the changes are internal and you're not extending the size of the building. However, you'll need to check with your local authority, as in certain areas, permitted development on garages has been revoked where it may affect the capacity of on-road parking. 

Garden guest room

Mulroy Architects Ormond Road garden room bedroom - grand designs

Image: This space in north London by Mulroy Architects is used as a home office and piano room, but also contains a sofa bed and bathroom to make for an occasional guest room. They required planning permission to enlarge the height to 3.5m. 

While a timber frame garden room beig enough for a bedroom is likely to cost around £10,000, costs are likely to be much larger to make a habitable bedroom space, including glazing, heating and insulation. 

While some garden rooms are not subject to building regulations, if you're looking to create an extra bedroom in yours with sleeping accomodation, you will need to ensure the structure does conform to them. 

To build a garden room under permitted development, they can’t be self-contained accommodation or used as primary living space. In essence, you can add a bathroom or kitchen providing it is only for incidental use and you might have to demonstrate this if you apply for a certificate of lawfulness to the council. Permitted development also only extends to a building up to 2.5m in height. 

Mezzanine level

6 Scandinavian Loft mezzanine bedroom

Image: This project by Scandinavian Loft has made the most of every inch, with a platform bed accessed by stairs that double up as storage

A mezzanine is a clever idea if you’re lucky enough to have some double-height space. It can be left open to maintain a light and airy connection with the room below, but for a bedroom, enclosing it may be better for privacy. 

Mezzanine are required to meet building regulations, but won't need planning permission unless it's a listed building. If your mezzanine forms
a bedroom that is in effect a third storey, or is part of other major works, you must comply with building regulations that relate to fire safety. The floor area of a mezzanine must be no greater than 50 per cent of the floor area of the room below for this reason. 

Extend out 

le humaine home extended with cantilevered box for extra bedroom - grand designs

Image: The renovation of this family home in Montreal, Canada by Nature Humaine saw an extra bedroom added with a cantilevered upper storey extension to make space for a new baby – an alternative to a double storey extension. 

Extending your home to create another bedroom largely means looking at a two-storey extension to avoid it being located on the ground floor. It may be possible to build two storey extensions under permitted development, but at present, the design parameters are limited. However, this could soon change under a proposed relaxation of the rules around double storey extension under permitted development

Find out more about planning an extension


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