We’ve written an article before about the types of loft conversions. There we briefly tackled the issue of cost, but largely skirted around the issue. As with all these things, costs can vary wildly depending on the structure we’re working with and the finish required.

Having said that, one of the most common things we get asked for is a ‘rough cost’ for things like loft conversions. Many people, quite rightly, think about loft conversions when considering ways to increase living space within their home, or to potentially add value. But a big deciding factor in whether it’s worth pursuing is cost. People don’t know whether to expect £5,000 or £50,000! So we’re tackling the issue again, this time with a bit more meat on the bones…

What costs are involved in a loft conversion?

Firstly, here are some of the things you might need to factor into the cost of your loft conversion:

  • Professional fees (architect, structural engineer):
  • Planning permission (may be required, depending on the work)
  • Building control fees
  • Steel joists
  • Timber
  • Floorboards and cladding
  • Insulation
  • Plasterboard and plastering
  • Scaffold hire
  • Windows or roof lights
  • Staircase
  • Electrical fittings
  • Plumbing fittings and radiators
  • Doors, skirting, fittings
  • Paint, carpets and other finishing touches
  • Labour, including builders, electrician, plumber, maybe more depending on the level of finish you require.

Depending on the structure of your build you might also need to factor in costs for building one or more dormers, and roofing, fascias and guttering associated with that. And if you’re including an en-suite, there’s the cost of the suite and additional plumbing work.

So that’s a lot of things to think about, each with a cost associated with it.

What factors affect the cost of a loft conversion?

  • What type of conversion you need. This will depend on your roof structure.
  • Whether any alterations are needed to the floor below to accommodate the staircase
  • Whether the hot water tank needs moving
  • How much plumbing you need – is it just for heating, or will there be a bathroom up there too?
  • The finish you’re after.

How much does a loft conversion cost?

We’ve spilt costs across three of the main types of conversions (find out more about these in our previous article) to give you the best guide we can. Please note, these costs don’t include decorating and furnishing your loft conversion.

Velux, or roof light, loft conversion

This basically involves working within the existing loft space and is the cheapest option.

As basic conversion, without a bathroom, could start at around £20,000. It would be safer to assume a cost of around £25,000 (net of VAT).

Dormer conversion

A starting cost for a conversion where you’re adding two dormers would be around £25,000.

However, a better figure to work to would be up to £40,000. This would allow for a bathroom as well.

Hip to gable or mansard loft conversions, involving changing the roof structure:

Where more extensive work in involved in changing the roof structure, cost shoots up accordingly. A starting cost for this type of conversion would be around £40,000, going up from there.

How can I save money on my loft conversion?

It’s a very good idea to get some professional help with a loft conversion project. However, once you’ve had a specialist carry out the structural bits of the conversion for you, you might be able to take care of many aspects yourself. Installing insulation, floor boards, partition walls and plasterboarding are all perfectly achievable for a competent DIY-er. Taking these jobs on yourself could save you some money.

The most expensive parts of a regular loft conversion project tend to be the structural aspects, dormers and the bathroom/shower room. If you can avoid either of these, you’ll make a saving. As soon as work involves significant structural work to the roof, costs can go up.

But you must remember that all loft conversions must comply with current building regulations if you want to add the maximum value to your property.

Sometimes, the best course of action is to accept that a loft conversion just isn’t the right option. Costs may outweigh the return. When it comes to making this decision, it could be time to research your local property market. Try to see what your home might be worth with the conversion and see if that outweighs the costs of taking on the work.