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Bungalow Loft Conversions: A Cost-Effective Way to Add Extra Space

Bungalow Loft Conversions small timber frame extension ideas
(Image credit: Simon Maxwell)

Bungalow loft conversions are increasing in popularity thanks to how easily they can often be extended and their stylish finish. 

Adding an extra bedroom, office space or home cinema room has never been easier thanks to how convenient it is to extend a bungalow upwards. Most have oodles of headroom and readily lend themselves to the addition of stairs and roof windows. 

The average bungalow in Britain has heaps of potential and better still, it’s often possible to add extra loft rooms for a budget price.

Do I Need Planning Permission for a Bungalow Loft Conversion?

Most bungalow loft conversions don’t require planning permission and come under Permitted Development (PD) as long as they meet some key conditions.

If your design doesn’t comply, then a planning application will need to be made, as it will for bungalows in Conservation Areas or Areas of Outstanding Natural Beauty and National Parks.

One potential restriction on PD conversions is the total volume that’s allowed for new additions such as dormer windows or hip-to-gable conversions which must not exceed 50m3 (or 40m3 for terraces). 

However this refers to new space added to the existing loft, so unless you’re sticking something the size of a blue whale on your roof it shouldn’t be an issue (although any previous roof extensions count towards this limit).

The other key planning permission rules:

  • You’re not allowed to raise the height of the roof 
  • On the main elevation facing the highway (normally the front) you’re not allowed to construct dormers or anything that projects out from the roof, although you can install roof windows 
  • Any dormers or other roof extensions should be set back minimum 200mm from the original eaves 
  • Any new side-facing windows must be obscure-glazed and the opening casements must be at least 1700mm above the floor.  This is especially important in homes where with a gable wall facing the front because all roof windows will be side facing 
  • No balconies or raised platforms are permitted
  • Materials must be similar in appearance to the existing bungalow  

Bungalow Loft Conversion Guide

(Image credit: Getty Images)

Even where a design ticks all the right boxes it’s still advisable to check with your Local Planning Authority before starting work because in some cases PD rights might have been removed. 

This could be because the original planning permission when the bungalow was built had a condition preventing further enlargement. Or the council may have imposed an Article 4 Direction on the local area withdrawing PD rights.

(MORE: A Guide to Building in Designated Areas

Bungalow Loft Conversion Guide

(Image credit: Getty Images)

How Much Does a Bungalow Loft Conversion Cost?

One of the big attractions of converting bungalows is that the costs are generally lower than for loft conversions in equivalent houses. 

In many cases, only a single lift of scaffolding is required, and not having to pay for extensive fire protection measures is also a bonus. 

But the biggest savings are likely to arise where you’ve already got a very spacious loft which doesn’t require the addition of bulky dormer windows, just some rooflights fitted flush with the roof. 

This sort of simple conversion would be likely to cost around £20k to £25k for a straightforward double bedroom design.  

Adding large dormer windows and an en suite bathroom can raise the total to around £40k. Most expensive of all, a full rebuild with a totally new roof could set you back as much as £65k.  

(MORE: Loft Conversion Costs)

What Factors Affect the Costs?

Much of course depends on the specification and the desired quality of fittings and finishes. 

These sums also assume that the existing foundations are sufficient with no requirement for further foundations or structural support. 

In terms of timescales, a typical bungalow loft conversion can be expected to take about six to eight weeks, although where a planning application is required or Party Wall Agreements have to be factored in you will need to add at least another couple of months to the overall programme. 

Is the Loft of my Bungalow Suitable for Conversion?

You typically need a minimum 2.5 metre clear space under the ridge to convert a loft

Bungalow Loft Conversion Guide

(Image credit: Getty Images)

A key test when assessing whether lofts are suitable for conversion is whether you can comfortably stand up and wave your arms around.

But some bungalows were built with shallow roofs which can make conversion unfeasible. 

Here are two possible ways round the problem:

Add new ceilings

First, it may be possible to ‘borrow’ some spare headroom from the existing ground floor rooms if the ceiling heights are particularly generous. 

This involves demolishing and rebuilding new ceilings at a lower level to form the new loft floor

Rebuild the roof

So an alternative solution may be to take the bull by the horns and completely rebuild the roof at a steeper pitch.  

Raising the height of the roof will however require planning permission and tends to be contentious, even with detached bungalows. 

It’s also the most expensive option although the likely superior quality of the end result can often justify the higher costs. 

If you do opt for this approach then it might be worth going the whole hog and re-designing the bungalow as a house. 

In other words, extending the existing walls by an extra storey with a new roof constructed on top. 

Designs of this type often employ lightweight timber frame or structural insulated panel construction. And recent changes to PD mean there should now be a better chance of getting planning consent for extra storeys. 

Supporting the New Floor  

Probably the biggest question at the design stage is how to support the new floor, which will depend on the type of construction. 

Most bungalows built up until the late 1960s had traditional ‘cut timber’ roof structures supported partially by internal load-bearing walls. 

These were later superseded by modern prefabricated roof trusses spanning across the main walls without any intermediate support. 

Whilst load-bearing internal walls can potentially be utilised for supporting new floor joists, the plain fact is, foundations in all types of bungalows were not designed to support additional loft rooms. 

So a structural engineer will need to provide calculations at the design stage to confirm how the new loadings can be safely accommodated. In some cases this might require investigations with trial pits excavated to confirm the adequacy of the foundations. 

Bungalow Loft Conversion Guide

(Image credit: Getty Images)

In a typical conversion, new floor joists are placed alongside the existing ceiling joists in the loft and are supported each end by large steel beams positioned close to the eaves. The correct size of joists and steels must be determined by a structural engineer.

In recent years a simpler solution has been developed which entirely dispenses with the need for manoeuvring enormously heavy steel beams in confined spaces and cutting into party walls.

Instead a series of lightweight telescopic aluminium joists are placed alongside the existing ceiling joists. 

Known as Telebeams these also have the advantage of being able to provide support to modified roof structures without disturbing party walls.

(MORE: Party Wall Act)

Chartered surveyor Ian is the author of eight popular Haynes House Manuals and is a director of He is also in the process of adding a large extension to his home.