Despite some pretty dismal summers and utterly freezing winters, here in the UK we seem ever optimistic about the weather, determined to do everything we can to ‘bring the outside in’ — and what better way to take advantage of any rare glimpses of sunny weather than with doors that allow you to open up an entire section of your home to the outdoors.

What are my options? French Doors

  • Perfect addition to period homes;
  • Usually provided by window suppliers so can easily be designed as part of a new window scheme.

Sliding Doors

  • Forget the 1960s problems — more modern, sleek designs have now been introduced, making the frames almost invisible;
  • They can be designed as ‘pocket doors’ that slide away into cavities within the wall;
  • A great option for large apertures as each panel can be far wider than the typical maximum width of 1.1m for a folding sliding door panel.

Folding Sliding Doors

  • Give a clean, sleek finish and usually run on tracks that lie flush with the floor. If your opening is relatively small (around 4m or less), folding sliding doors will not block much of the opening when open;
  • Bear in mind though that this style of door stacks – when open – at a 90° angle to the track, so there needs to be a clear area at one side of the opening (either inside or out) for them to sit.

What materials are available?

  • Aluminium is the perfect choice for contemporary homes, allowing for very slim frames on doors and comes in a range of finishes;
  • If you are considering French doors because you feel they will fit in with your traditional-style home, timber will be the best option. Softwood will be the cheaper option, but will require a little more upkeep to remain in good condition than those with hardwood frames;
  • Doors with aluminium exteriors and timber interiors offer the benefits of seeing the beauty of the timber inside, whilst the aluminium exterior has greater resistance against the elements.

How does glazing differ from one door to another?

With the trend towards minimal sightlines (as low as 60mm) the performance of the glazing becomes increasingly important. Any large expanse of glazing will mean potential heat loss and you will need to choose carefully. All new and replacement windows must comply with Part L of the Building Regulations, which states that any glazed doors must achieve a minimum U value of 1.6, but you can often pay for upgrades from the standard glazing offered — reducing U values much further (on triple-glazed models especially).

Standard double glazing is commonly 24mm or 28mm thick. It often has a low E-coating which improves energy efficiency and will be toughened or laminated safety glass that complies with Building Regulations.

How do level thresholds work?

A level threshold (where the floor track that the doors run on is flush with the floor and the internal and external floor levels are the same height) is perfect for those with mobility issues and also works well with young children, allowing them to run in and out without constantly tripping up.

However, to work successfully, the space must remain watertight and so good drainage must be incorporated into the design (try ACO’s Doorway Drain). The floor in front of the threshold should slope gently away so that water cannot pool in front of the doors.

Another option is to build up the external floor level with a timber deck, that gives the appearance of a level threshold without the risk of water ingress.

What will they cost?

Expect to pay from around £1,200 per linear metre, plus VAT. You will probably be asked to pay a deposit, with the full amount due on delivery.

How do I compare suppliers?

“The price range is very wide, but what a lot of clients don’t seem to realise is that the differences in quality are also very wide,” says Charlie Sharman, Managing Director at Cantifix (who supply Schuco doors). If you’re choosing aluminium, check that the frame has been designed to be thermally broken, which will combat heat loss and condensation problems. Kloeber’s range, for instance, is made up of extruded aluminium profiles insulated with a polyamide thermal break.

Track systems also vary. Ideally they should be stainless steel and the mounting on which they sit should be extruded aluminium. The robustness of the hinges is another differential between the better and not-so-good models. Some systems use a cast aluminium hinge, which will never last with regular use and are easy to break into. Hinges on the more desirable door systems are either extruded aluminium or stainless steel.

Door systems like this are a potential area of weakness from a security point of view, so you should ensure that the doors have at least a three-point (preferably five) stainless steel lock.

The gaskets between the doors are worth checking too. They should be tight enough to provide sufficient weather protection, but as the folding doors can be a trapping hazard, soft enough to prevent serious injury if anyone gets their finger stuck.

And while you’re there, you should compare the different weather ratings of the various systems, along with security standards and the running track system — smooth operation is a must.

Other key tips – according to Centor – include ensuring reliable operation by asking to see evidence of cycle testing (upwards of 25,000 actions). “Like a sail, the force placed on folding doors by prevailing weather conditions gets proportionally greater the larger the area,” says a spokesperson. Ask for pressure testing data — 1,200pa constant/1,800pa gusting pressure is a good standard.

One factor that the supplier can’t control is the opening in your wall — and as anyone with experience of building sites knows, there is a degree of room for error. So make sure that your door allows for more vertical and lateral adjustment — particularly useful for allowing for any movement over time.

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