There are a number of considerations when buying either French doors, patio doors or internal French doors. Firstly, it’s vital that you understand the differences and constraints of each design.

The term ‘patio doors‘, otherwise known traditionally as sliding doors, has morphed over time to cover all types of doors that open out either onto your garden/patio area, or in to your living area, or simply slide open/closed. These include French doors, folding sliding (bifold doors) and  of course sliding doors. All types operate differently and offer you certain different benefits. In this article we relate specifically to the difference between “French doors” and “sliding patio doors” and what to look for when buying them.

WHATS THE DIFFERENCE AND WHICH ONES SUIT YOUR REQUIREMENTS?

Both sliding patio doors and French doors come in a range of sizes, but the key differences are as follows:

French doors (or French windows) are traditionally hinged double doors which mainly open outwards, (or inwards by design). When the doors are open you have full access to the width of the opening into which they are installed. However, you are constrained by the maximum leaf size which is generally approx. 900mm/leaf. So a maximum opening width, with both doors open, is approximately 1800mm wide. Having access to the full width of the opening at smaller sizes is great for access particularly into smaller properties, or smaller gardens where space internally or externally is critical (size range 1200mm wide to 1800mm wide).

Sliding Patio doors give you availability of achieving much wider opening spaces with sliding doors going to standard general widths from 1600mm right up to 4200mm. The only problem with sliding doors is that only approximately 50% of the space can be open at any one time, as when the doors are open they are still in part blocking the opening space you have. Sliding doors can be beneficial with restricted space, either externally or internally, as they do not protrude from the line of you wall when open. This is a definite benefit in restricted areas!

However, over the years, sliding patio doors have declined significantly in popularity, with increasing volumes of folding sliding doors now being offered. These give the benefits of both French doors, opening up the full width of the available opening, with widths up to 4200mm similar to patio doors being completely open, but also keeping the amount of space taken up to a minimum.

SO WHICH ONES SHOULD YOU BUY – FRENCH DOORS OR PATIO DOORS?

There are lots of factors to consider

Cost – The cost varies, dependent on actual opening size you have. If you looked at cost per square metre of the opening, then sliding patio doors will work out around 10-20% cheaper at sizes bigger than 1800mm – as locking mechanisms and hardware generally together with manufacturing methods are all slightly more cost effective than French doors. At sizes above 1800mm, the cost of French doors can become restrictive as additional windows or sidelights are required to fill the opening.

Security – All types of exterior patio, or French or sliding doors come with security features, but here are some important features to look out for when buying:

Patio Doors (sliding). You need to ensure your doors have the following as a minimum

• Multipoint lock, with security hooks to prevent the doors being levered open
• Lockable drop bolts are a great addition on the sliding leaf
• Anti lift devices on the doors to prevent them being forced upwards and lifted off their sliding mechanism
• Lockable anti bump cylinder lock to prevent the barrel being forced
• The doors need to have toughened double glazing and ideally have Secure by Design approval – ie they have been tested to a standard approved by The Association of Chief Police Office (A.C.P.O)

French Doors – be on the look-out for these:

• Multi point locks are a must on French doors, with either 3 point or 5 point locks locking the doors and frames together when closed
• French doors should be supplied ideally with cover splines to cover the rebate gap between the doors where they meet. This is the weakest point on a French door
• All lock barrels should be supplied with “anti bump” cylinders for extra security
• Ideally the doors should be supplied with opening restrictors or if not, fit some yourself. This prevents damage caused by the doors being blown open in the wind – a common problem in the glorious British weather!

Perfomance – With both door systems you need to consider the thermal efficiency or U Value on offer (the lower the value, the better the performance). This is covered by Part L of the Building Regulations. You need to ensure that they are double glazed with toughened glass units that comply with BSE 12600 and 12150. Again these are a must for both safety and performance (look for the toughened glass mark usually in the corner of the glass unit).