A loft conversion is a popular home renovation that adds value and space to your property for less time and money than building an extension. But exactly how long does a loft conversion take to build? 

How Long Does a Loft Conversion Take?

In general, a loft conversion takes 8-12 weeks. The exact time will depend on the type of conversion, the amount of structural work required, how you plan to use the space and whether you need planning permission. As a rule, the more complex the conversion, the longer the time and the higher the cost.   

In order of complexity, the most common types of loft conversion are rooflight, dormer, L-shaped, hip-to-gable and Mansard. 

How Long Does a Rooflight Loft Conversion Take?

A straightforward rooflight loft conversion takes 6-8 weeks and costs anywhere from £16,000-£22,000. This is the simplest type of attic conversion: assuming you have sufficient head height, you can just add windows in the roof and convert the interior for living.

Rooflight loft conversions don’t usually require planning permission as long as you don’t extend the internal space. However, features like en-suite bathrooms will add to costs and timelines. 

How Long Does a Dormer Loft Conversion Take?

A dormer loft conversion takes 12-16 weeks and costs £50,000-£80,000 depending on the size and the number of dormer windows you install.

These come in all shapes and sizes, some almost as long as the roof. It’s a great way to gain space, light and headroom without too much complex structural work. And, as long as the dormers aren’t on the front of the house, you shouldn’t need planning permission. 

How Long Does an L-shaped Loft Conversion Take?

An L-shaped loft conversion takes 10 to 16 weeks and costs £40,000 - £80,000. It’s similar to a dormer but runs the length of both wings on an L-shaped house.

Connecting up the wings in this way opens up almost the equivalent of another floor. If your house is large enough you may even be able to partition the space into multiple rooms. 

How Long Does a Hip-to-Gable Loft Conversion Take?

A hip-to-gable loft conversion takes 8 to 12 weeks and costs  £35,000 - £50,000. It involves replacing one ‘hip’ end of a sloping roof with a vertical ‘gable’ wall.

The style works on anything, from detached homes to bungalows and can even be used to extend a previous rooflight or dormer loft conversion. However, you usually need planning permission to alter the roof shape in this way.   

How Long Does a Mansard Loft Conversion Take?

A Mansard loft conversion takes 16 to 20 weeks and costs £40,000-£80,000. This is the most complex type of attic conversion as it involves replacing an entire length of the roof with a flat roof and almost vertical wall.

Mansards tend to suit a wide range of homes, even mid-terraces, and are normally installed on the back of a property. It’s a major alteration, though, so you need planning permission.  

What Can Cause Time Delays on Loft Conversions?

As well as the factors above, there are some other considerations when calculating how long a loft conversion takes overall. All conversions involve some outdoor work so if the weather is bad and the days short it will take longer. If possible, plan for a spring start to avoid delays.  

Like all home renovations, how long a loft conversion takes also depends on whether you are living in the house at the time. Loft conversions aren’t as disruptive as other types of home renovation so it’s not as big an issue as, say, renovating your only bathroom. However, work always progresses faster on an empty house as builders can work longer hours and don’t have to clean up at the end of each day. If you’re planning a loft conversion as part of a whole-house renovation, consider moving out for the duration to save time and money overall. 

Finally, how long a loft conversion takes depends on whether you need planning permission. This takes anywhere from 10-16 weeks to obtain, so apply well in advance to avoid delays. 

To discuss in more detail how long a loft conversion takes, get in touch and we’ll be happy to advise.