How Much Does a Loft Conversion Cost?

A loft conversion costs $7,000 to $67,600, averaging about $20,000. This translates into $50 to $150 per square foot. You’ll pay $9,000 to $34,500 to build a loft from scratch and $14,300 to $67,600 to turn an existing one into a bedroom with an en suite bathroom.

If you have an existing loft, you may be able to increase your property value and usable living space by converting it into a room. Keep these cost factors in mind as you research this project.

Average Cost to Convert a Loft Into a Bedroom

Converting a loft into a bedroom costs between $10,000 to $22,000 on average. Although this project isn’t as expensive as a full addition, it usually requires many of the same services, including new plumbing and electrical work.

Average Cost of Loft Conversion With En Suite

Converting a loft into a bedroom with an en suite bathroom ranges from $14,000 to $67,000. This includes the cost to enclose the bedroom and the price to install a bathroom, which is $5,000 to $35,000 on average.

This range may not include running a new plumbing line up to the bathroom space. The cost to install plumbing ranges from $400 to $1,900.

Cost of Converting a Loft Into Another Room

Loft conversion costs $7,000 to $25,000, depending on the type of room you’re turning your loft into. For example, transforming a loft into a storage space will be less expensive than turning one into a bedroom that needs additional electrical outlets, wiring, and possibly plumbing.

For home office loft renovations, add built-in shelving and resilient flooring for high traffic. If you're using the space for storage, skip the window and put in a skylight to maximize wall space and save on costs. If you're renovating a loft into a gym, install more light fixtures and hardwood flooring for high-impact workouts.

Dormer Loft Conversion Cost

The cost of flat-roof dormer loft conversion ranges from $12,000 to $56,000. Since these types of homes often have roofs with no pitches, you’ll need to ensure that your setup has sufficient drainage to maintain the integrity of your structure. Installing gutters and downspouts costs $600 to $1,600 on average. A flat-roof dormer is appropriate when you have to maximize every inch of available height for the loft.

Loft Conversion Cost Breakdown

Because converting a loft is similar to building a house in many ways, it also requires a lot of similar projects and related expenses. These can include anything from adding new flooring to installing new electricity. In the table below, find out what you can expect to pay for the most common aspects of a loft conversion.

Framing and Building Walls

The cost to frame and build new interior walls ranges from $1,400 to $6,000 and is roughly $4,000 on average. Most contractors charge $4 to $10 per square foot for labor, and materials cost an additional $3 to $6 per square foot. 

Ducts and Vents

The cost to install ducts and vents in a loft conversion ranges from $500 to $2,000.This breaks down to an overall price of $10 to $20per linear foot for labor and materials. 

Ceiling

The cost to install a new ceiling in a converted loft ranges from $900 to $2,600. The style of ceiling you choose will have the biggest impact on price, with simple drywall builds costing as little as $1 to $3 per square foot and elaborate coffered ceilings costing as much as $20 to $30 per square foot. 

Paint

The cost to paint a room ranges from $1,000 to $3,000 on average, though you can save on costs by doing a project like this yourself. Pros charge $20 to $50 per hour, but paint supplies typically cost between $3 and $200, so it’s worth it to consider going the DIY route on this one. 

Flooring

The cost to install flooring in a converted loft ranges from $1,500 to $4,500. Materials cost between $3 and $22 per square foot, and pros charge $60 to $120 per hour for labor.

Egress Window

The cost to install an egress window ranges from $2,500 to $5,400. Windows typically cost $100 to $700 on average, and the type of window you choose can also impact the price. For example, prefabricated egress windows cost less than custom ones.  

Stairs

The cost to install stairs leading up to a converted loft ranges from $1,000 to $3,100. Factors like the location of the new stairs, the materials, and whether you have to excavate or clear the area beforehand all impact how much you’ll pay. 

Lighting

The cost to run new electrical wiring for lighting in a converted loft ranges from $500 to $2,300. Fortunately, this is about half of what it costs to rewire because it’s cheaper to add new wiring than to repair old wiring. 

Plumbing

The cost to install plumbing ranges from $400 to $2,000. What you pay depends on the piping material you choose and the project's scope. 

Structural Engineer and Architect

Hiring a structural engineer costs$400 to $800. This price covers a basic inspection and consultation to confirm that the structure can support a loft. The cost to hire an architect ranges from $2,000 to $9,500. This usually includes the project plans and drawings, but pros may also charge an additional percentage of the total project in their fees. They’re more likely to do this if you’re hiring them to supervise the project.

Raising a Roof

The price to raise a roof ranges from $15,000 to $125,000. You might need to reconsider this project if your existing structure can’t provide at least 7 feet between the loft floor and ceiling.

Loft Renovation Cost Factors

Though the overall price of a loft conversion depends mostly on the size and features of the room, the type of house can also impact how much you’ll pay. 

• Average Cost of a Loft Conversion in a Terraced House: If you want to convert a loft in a two-bedroom terraced house, there are a few additional steps you may need to take. First, check with your HOA to see if you must follow specific rules. You may need to pay extra for building permits, for example. 

• Cost of a Loft Conversion in a Bungalow: The cost of a loft conversion in a bungalow depends on the position and pitch of the ceiling and whether there’s room for a staircase. A bungalow often has high, vaulted ceilings but a smaller footprint. To make the loft conversion work, you may need to lower the ceiling or make space for a permanent staircase.

• Semi-Detached Loft Conversion: Cost factors for a loft conversion in a three-bed, semi-detached house depend on the layout. If you have to install a dormer to provide adequate standing room, you may have to get approval from your HOA. Plus, you’ll need to budget for the additional cost of installing a new dormer. 

• Victorian House: Converting a loft in a Victorian house usually involves dormer installation or other work on the ceiling. Homes from this period often have a high roof pitch of 12-to-12 or greater—compared to the standard 4-to-12—so the odds are high that you’ll need to lower the ceiling first.

DIY Loft Conversion vs. Hiring a Pro Near You

A loft conversion is a complicated project that can significantly affect your home’s safety and structure. This job is better left to a local general contractor. Remember to read reviews and request estimates from at least three contractors when you're ready to start.

FAQs

What is a loft conversion?

A loft conversion is the process of converting a loft (or sometimes an attic space) into a fully functional room, complete with walls, ceilings, lighting, and sometimes plumbing. 

What’s the difference between a loft and an attic?

A loft usually has partial walls on at least two sides and is about the size of one or a few rooms. Meanwhile, an attic is separate from the rest of the house and usually spans an entire floor.

Do I need planning permission to convert a loft?

Converting a loft usually requires a building permit. This is because it’s a larger project that also changes the structure.

How long does a loft conversion take?

A loft conversion can take a few days to several weeks. It depends on the size of the room, the current layout, and features that take more time, like a bathroom.