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The cost of a loft conversion

The cost of loft conversions can vary depending on the type of loft conversion you want, along with the size of your home. When it comes to conversions, lofts are not always simple and as straightforward as many believe.

Many conversions will have to be done according to building regulations, structural work that may need to be done, etc.

The most common types of loft conversions include:

  • Dormer loft conversion: this is the most common type of loft conversion, which include an extension of the roof, adding walls (building out) from the roof to increase space, etc. A dormer loft conversion works with most types of homes.
  • Mansard roof conversion: this type of loft conversion is quite extensive, as it deals with changing the roof’s structure. While this type of conversion adds the most space, it does greatly alter the exterior of your home.
  • Hip to gable conversions: this is a great option for semi-detached and detached homes. A hipped roof is a roof with a sloping side, in addition to the front and back slopes. In this type of setting, the current loft space is usually small. In order to create a larger loft, you’ll need to add on to your property. This is done by replacing the sloping roof with a vertical wall (also called a gable). This provides the extra space needed to make the loft space usable.
  • Adding a loft room: this is one of the easiest conversions. If the space is already the correct height (2.2 m or more), then all you have to do is add stairs, windows, skylights, insulation and reinforce the floor.

Typical Prices for a Loft Conversion

The cost will greatly depend on the type of loft conversion you choose. Let’s take a look:

  • Room in loft: this is the easiest conversion and the least expensive. The cost is usually between £20,000 and £28,000 for a standard sized house. Prices tend to be higher in London and the south east, as tradespeople are in higher demand.
  • Dormer loft: this option is also an easier choice and they’re also inexpensive. A dormer loft conversion tends to run from £31,000 to £58,000 depending on the loft size, etc. The average cost for this type of conversion runs about £45,000.
  • Mansard loft: this conversion is generally more complex and one of the more expensive. It can run anywhere from £45,000 to about £70,000. The average cost runs around £58,000.
  • Hip to gable loft: these are often a more expensive choice, as this type of conversion is more complex. Prices for this type of loft conversion start at £42,000 and can run up to £64,000. The average cost is £54,000.
  • Bungalow loft: any of the three types of loft conversions can be done to a bungalow, with costs generally starting at £30,000 and running up to £70,000.

Loft Conversion Stages

As with any building project, a loft conversion will go through various stages. Calculating the cost of each stage can be challenging. Builders generally don’t separate the costs for each stage of the build. However, some builders will accept being paid in stages as each one is finished.

1). Conversion plans: it’s best to hire an architect who will draw up the plans for your loft conversion. They’re professionals who are trained to figure out exactly what needs to happen with the build. An architect will also be able to include cost calculations for the conversion. The price will vary, but an architect will generally run about £1,00 plus VAT.

2). Planning permission: most loft conversions don’t require planning permission, as these are usually known as permitted developments. However, there are times when it will be necessary to obtain planning permission, where you’ll need to apply for a permit, which costs £172 in England.

3). Building regulation: the loft conversion will need to be inspected by the building regulations department in your locale. This is because the building needs to be constructed according to the rules, which include fire safety, floor strength, etc. Submitting plans for inspection and having on-site inspections generally costs about £400 and £800.

If your property adjoins another, you’ll have to obtain a Party Wall Agreement. These generally run into about several thousand pounds, depending on the complexity of your plans.

One more cost, is a bat survey. Yes, we mean the squeaky flying mammals that eat bad insects. This isn’t always needed, but if you have bats in your belfry (loft), then you’ll need to have it checked. This can cost around £400.

4). Loft building: most of the expense of the loft conversion will be found here. These costs will involve all aspects of the build itself, involving everything from external work and scaffolding, to interior walls and flooring, electrical wiring, etc. The cost will vary depending on the type and extent of conversion you’ve decided on.

5). Other conversion costs: will involve everything from finishing off the loft, such as whether or not you’re adding a bedroom plus a bathroom, which is more expensive than just adding a bedroom. Other factors will include the number of windows & skylights, the type of roofing material, reinforcement of trusses, etc.

Timeframe for Loft Conversion

Building the loft conversion can take anywhere from six to eight weeks. It will depend on how complex the plans are. Other factors that may extend the time include gaining planning permission, working through a Party Wall Agreement, which will need to be negotiated.

Fortunately, in most cases, you should be able to stay in your home during the conversion process.

Keep Loft Conversion Costs Down

There are ways to keep the cost down on your loft conversion including:

  • Hiring specialists for each role in the process.
  • Hiring reliable, experienced builders who can manage the project, including any complications.
  • Ensuring plans for any plumbing need in the conversion is over plumbing that currently exists in your home.

The calculations included in this article are current as of 2020. We hope the guide helps you to estimate what your loft conversion could cost.

Written By
ecoTrus Manager
May 10, 2023