Loft conversions: troubleshooting and finance

From finance to planning permission, find out how to overcome the most common problems when dealing with loft conversions

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If you are considering adding a loft conversion to your home, either to add space or value, there are a few things that you are going to have to consider before you begin. Loft conversions are potentially the easiest and most popular way of extending a home.

Converting a loft is usually more cost effective than an external extension, but finance is still something that you need to think about. You will also have to look into your planning permission and building regulation requirements to find out if a loft conversion is possible in your property.


Related articles: The beginner’s guide to converting your loft | Planning and costing your loft conversion | How to design a loft conversion | 10 great ways to use a loft conversion


How to pay for your loft conversion

Average loft conversions costs £20,000-40,000 and most conversion companies don’t offer finance (unlike kitchen firms). But financing can be an expensive option, so a mortgage or personal loan would, in my opinion, be a better option,’

Mortgaging a loft conversion

If you are mortgage-free, this will be straightforward. Contact your bank or building society to see what it can offer. If you currently have a mortgage, though, remortgaging will be the cheapest way. Check first that you won’t have to pay a penalty to do so.

If you are on a fixed-rate deal that’s not due to end for another year or more, you may be better off waiting because otherwise you will face fees. Even if you are on a fixed rate, however, some banks may let you take out a new mortgage that runs with your current deal. It is always worth asking.

A personal loan

If you cannot remortgage and want to start your loft conversion now, a personal loan is another option – but these are more expensive. Most comparison websites show loans start at 7.5 per cent and in practice it’s hard to get one for under 11 per cent, even with a good credit rating.

Compare this to mortgages, with interest rates ranging 2-6 per cent at the time of writing. Also, you can only take out a personal loan for up to £25,000. If you need more money, you can look at a secured loan, but these are best avoided as interest rates start at 12 per cent.

Plan your loft conversion payments

‘The average cost of loft conversions is roughly £28,000, with most of our customers using a mortgage or savings to cover the expense,’ says Nigel Brown from NK Lofts. ‘Based on that total, this payment plan can be used as a guide to when and how much you will typically need to pay, which can help with the decision of whether to use savings, a loan or a new mortgage to cover each stage:

  • Before the start date: a 5 per cent deposit = £1,400. This will guarantee commencement of the work.
  • Week 1: on the start date, pay 25 per cent = £7,000 to cover materials and part of the labour upfront.
  • Week 3: plasterboard stage. Pay a further 50 per cent = £14,000, to cover labour and further materials.
  • Weeks 5-6: final payment. The remainder = £5,600 — but only pay after all the work is completed satisfactorily.

‘Choose a company that will give you insurance,’ advises Nigel. ‘Reputable firms will be members of the Federation of Master Builders (FMB), The Guild of Master Craftsmen etc. If they can’t offer insurance, avoid them. A ten-year guarantee is also normal, but the homeowner should ensure they receive the relevant certificates — for example, electrical and Building Regs approval. Without these, it will be hard to sell the property in the future.’

Common loft conversion problems

Converting your loft is possibly one of the easiest and most popular ways of adding valuable space to your home. However, there are a few common hurdles that you will have to overcome if you want your conversion to be a success.

Insufficient headroom

If standing room is an issue in the loft space, you need the thinnest insulation materials possible. You could try using multi-layer reflective foil insulation materials, but you will have to first make sure your local authority building control department is happy with this. You can also pinch a little extra headroom where you need it above the stairs or a WC by positioning a rooflight – these will, typically, give you an extra 15cm of clearance.

The header tank is in the way

Header tanks for central heating and the cold-water supply can be relocated elsewhere in the loft, or eliminated by switching to an unvented plumbing system. This is provided you live in an area with a local water pressure of at least 1.5 bar, as these systems use the mains pressure (rather than gravity). This can result in more powerful showers, too.

Difficult neighbours

If you live in a terraced or semi-detached house, your neighbours can’t prevent you from converting your loft space, even if you need to cross onto their property for access. You will need to give them notice under the Party Wall Act (England and Wales), however. For more information, go to

Leasehold restrictions

If you live in a flat, you will have to get planning permission for a loft conversion as there are no PD rights with flats or maisonettes. You will also need to check who owns the loft itself if your home is leased. If only your property has access to the space, you may be able to negotiate with the freeholder to buy the space so that you can convert it.

No soil pipe for a bathroom

If you want to add a WC in your new loft, but there is no suitably located existing soil stack, you will need to add a new one or, if this is too expensive, you can install a pumped macerator system (try Saniflo).


Planning permission and building regulations

Converting your loft does not usually require permission, but increasing the volume of your roof does constitute an extension and so consent may be required. The good news for anyone in England is that most homeowners can add a significant extension to their loft without having to make a planning application — under Permitted Development (PD) rights. This applies even if you have extended your home already, as long as you haven’t used up all of your PD rights. (Log on to for more information.)

You can add roof extensions at the back or side of a detached or semi-detached house up to 50m³ in volume, or up to 40m³ to a terraced house, provided you do not go any higher than the existing ridge height of the roof.

For dormer loft conversions, where a large flat-roofed box is added to increase the loft space, the guidance is that the dormer must be set back at least 20cm from the edges of the roof (the verges and eaves). If, however, you are building a hip-to-gable or gable-togable loft extension, it is allowed to go the full width of your house. (See the best designs for loft conversions for the design options.)

Planning permission will be required, however, on properties in a designated Conservation Area or Area of Outstanding Natural Beauty. Listed buildings require special consent as well, and you must check that PD rights have not been removed for any reason from your home. Scotland, Wales and Northern Ireland have their own rules for PD and modest loft conversions can often be undertaken here without the need for an application.

A guide to loft conversion building regulations

  • Although some loft conversions do not require planning permission, the work must comply with the Building Regs and the local authority must be notified, so that a building control officer can inspect the work.
  • Insulation and ventilation must meet energy-efficiency requirements, so all new windows and rooflights will most likely need to be double glazed.
  • The floor structure and roof are likely to have to be strengthened to take the additional load. Details of all these alterations will require approval.
  • If the conversion is to a two-storey house, the staircase from the loft to a final exit must be fully enclosed – unless you have installed sprinklers – and upgraded to ensure 30 minutes’ fire resistance, providing a safe means of escape.
  • This will usually mean doubling up plasterboard on ceilings and any timber stud walls, and upgrading to FD20 20-minute fire-resistant doors on all habitable rooms opening onto the stairway. Closing mechanisms are no longer required on fire doors, however (since 2007).
  • The stairway must not pass through any other room and a fixed staircase with handrails must be fitted. The maximum pitch angle is 42 degrees; the minimum headroom 2m overall, 1.9m in the centre.
  • Loft conversions to a bungalow don’t require an enclosed staircase, but each habitable room must have its own fire-escape window – a dormer window or rooflight – with a clear opening area for exit of at least 45x45cm. These windows can have locks to prevent the risk of children falling out of them.
  • If a conventional staircase won’t fit, a space-saver alternating-tread design or a fixed loft ladder can be used, providing it serves only a single room.
  • Linked smoke alarms must be fitted to provide an early warning in the event of fire.
  • For listed buildings where the historic fabric makes meeting all the special regulations difficult, there is scope to relax them at the discretion of your local authority’s building control officer.