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Replacing a window with French doors can completely change how a room feels. You’ll gain more natural light, easier access to the garden and a stronger connection between your indoor and outdoor space.

The overall cost depends on the doors you choose and how much work is needed to adapt the existing opening.

A straightforward conversion is very different from one that involves widening a load-bearing wall, fitting a new lintel and making good inside and out.

This guide explains the typical costs involved in replacing a window with French doors, what affects the price and what to check before comparing quotes.

How much does it cost to replace a window with French doors?

The average cost to replace an existing window with French doors is around £1,700, including materials and labour.

For a straightforward conversion, supply and installation typically costs between £1,400–£2,200. The final figure will depend on the size and material of the doors, the amount of structural work needed and any finishing work afterwards.

The doors themselves usually account for a large part of the budget, with supply-only prices typically sitting around £1,000.

If the existing opening needs widening or strengthening, structural work will increase the overall cost.

Get a quote to replace a window with French doors

The easiest way to understand what your project is likely to cost is to compare a selection of quotes from checked French door installers working in your area.

It helps to include the size of the existing window, your preferred door material and whether you think the opening may need widening.

What affects the cost of replacing a window with French doors?

The biggest difference between one quote and another is usually the amount of work needed to create the new opening.

The main cost factors include:

• Size and style of the doors

• Door material

• Whether the opening needs widening

• Whether a new lintel is required

• The condition of the surrounding wall

• Glazing specification

• Your location within the UK

• Any decorating, steps or decking needed afterwards

A standard set of French doors is usually around 1.2m wide and 2.1m tall. Bespoke sizes tend to cost more because both the doors and the structural opening need to be made to suit.

uPVC is usually the most affordable material. Aluminium offers slimmer frames and a more contemporary look, while timber suits many period homes but generally needs more maintenance.

If you’re comparing glazing specifications, our double glazing cost guide provides a broader breakdown.

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Additional costs to replace a window with French doors

It’s easy to focus on the doors and installation, then overlook the work needed around them.

Some of the possible extra costs you may face include:

New lintel or structural work

If the opening needs widening, a builder may need to install a new lintel to support the wall above.

Lintel replacement typically costs around £650–£1,000, depending on the size, material and complexity of the work.

Skip hire

Removing brickwork and the old window creates rubble and waste. Skip hire typically costs around £300, although the final price will depend on the skip size and your location.

Steps or decking

If the garden is lower than the internal floor level, you may need steps or decking outside the doors.

This can cost around £1,000–£5,000, depending on the size, material and amount of groundwork needed.

Decorating and making good

The wall around the new doors will usually need plastering, filling or redecorating once the installation is complete.

A painter and decorator typically charges around £32 per hour.

Labour costs to replace a window with French doors

A French door installer typically charges around £175 per day, while a labourer costs around £100 per day.

A straightforward conversion often takes one to two days, although structural work or difficult access can extend the timeframe.

Quotes may include labour, removal of the old window and making good, or these may be charged separately. Ask for an itemised quotation so you can compare like for like.

How long does it take to replace a window with French doors?

Most straightforward window-to-French-door conversions take around one to two days.

A simple installation may be completed in a day. If the opening needs widening, a lintel has to be fitted or significant brickwork is involved, allow closer to two days, followed by drying time before decorating.

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Do you need planning permission to replace a window with French doors?

Planning permission isn’t usually needed because the work often falls under permitted development rights.

However, you may need approval if:

• Your home is listed

• The property is in a conservation area

• Permitted development rights have been removed

• The new doors face a highway

• The work significantly alters the appearance of the building

If you’re unsure, it's best to check with your local planning authority before work begins.

Benefits of replacing a window with French doors

Replacing a window with French doors isn't just about changing the look of your home. It can also make the space feel brighter, more practical and better connected to your garden.

Some of the main benefits include:

• Bringing more natural light into the room

• Creating easier access to your garden or patio

• Making smaller rooms feel larger and more open

• Improving ventilation during warmer months

• Potentially increasing your home's appeal to future buyers

Many homeowners choose this type of project as part of a wider renovation, particularly when updating kitchens, dining rooms or rear living spaces.

Window to French doors cost calculator

The quickest way to estimate your budget is to think about:

• The size of the existing window

• The type of French doors you'd like

• Whether the opening needs widening

• Whether structural work, such as a new lintel, may be required

• Any finishing work, steps or decking needed afterwards

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This calculator provides a guide price only. For an accurate quotation, compare a selection of quotes from checked French door installers working in your area.

Window to French doors cost checklist

Before requesting quotes:

• Decide which style and material of French doors you'd like

• Measure the existing window opening, if possible

• Check whether the opening may need widening

• Think about any outside work, such as steps or decking

• Compare a selection of quotes from checked French door installers

• Check exactly what's included in each quotation

• Make sure your installer is FENSA or CERTASS registered so glazing work is notified to building control automatically

Every Checkatrade job is backed by our £1,000 guarantee

Up to £1000. Eligibility criteria and T&C’s apply.

Find a checked French door installer near you

Finding a checked French door installer through Checkatrade is straightforward.

When requesting quotes, it helps to include:

• The approximate size of the existing window

• Your preferred door material (uPVC, aluminium or timber)

• Whether you're replacing an existing window or enlarging the opening

• Whether you know if structural work is required

• Any photographs of the inside and outside of the wall

Providing as much information as possible helps installers prepare a more accurate quotation before visiting your home.

French door installation cost FAQs

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