Glazed doors cost guide
E Build It Estimating Service’s Adrian Wild compares the cost of the most popular types of glazed door configuration
Whether you prefer bifold, sliding or French doors, Adrian Wild gives you a starting point for your budget
Many self builders and renovators are keen to fit glazed doors to their project, in a bid to create a better connection between house and garden, as well as encourage more natural light into their homes. The first choice to make is between the different types of door on offer – namely French, sliding or bifold. You’ll also need to consider materials; should you go for PVCU, timber or aluminium?
Your final decision will be influenced by a wide range of factors, including your personal style preferences, budget, the size of the opening (if you need a load-bearing lintel, this will have a big impact on prices) and ongoing maintenance costs. Here’s what you need to know when specifying.
Sizing up
For smaller installations, bifold doors may not be the best choice. This configuration’s main selling point is that it allows you to create a clear opening (up to 90% of the width of the run) – but you won’t get the full effect on a small two-panel setup. What’s more, you can only include an independent access door if you have three panels or more. So for narrow runs, French or sliding units may be more appealing.
On medium-sized or large apertures (from around 2,200mm wide) bifolds and sliders come into their own. At this kind of size, the weight of the glass means you’re likely to need sidelights with a French configuration – automatically adding more framework and reducing the access. Sliding and bifold configurations can be specified for vast spans – in some cases as wide as 20m.
Aesthetics
If you want to bring the outside in, you can’t beat the uninterrupted views achievable with contemporary bifolds – when they’re open, that is. When these units are closed, the quantity of frame profiles actually breaks up the view compared to the larger expanses of glass possible with sliding doors; but with the latter, you can’t create such a clear opening. So whatever style you choose, the thinner the frame the better from an aesthetic point of view.
Bifolds and sliders can add an appealing contemporary twist to just about any project, whereas French doors tend to have a more traditional look – partly because they need a thick central mullion post for locking.
Thresholds
French doors are effectively regular doors, so they don’t tend to be flush to the ground. With sliders and bifolds, it is possible to achieve a flush floor track – which helps to create the outside-in effect. That said, you may want to specify a stepped threshold (which can still be very lowprofile) for maximum weather performance.
Practicalities
Each type of door has its own pros and cons. For instance, open bifolds may provide the best feeling of light, space and connectedness, but you need to account for how the panels concertina (if this is on the internal side, you’ll be limiting furniture positioning) and the fact they stack at one end.
Whichever opening configuration you prefer, be sure to scrutinise products carefully before making your selection. Are there any trip hazards from cills and lips, for instance, and how smooth and robust is the running mechanism? Be mindful of the strength and durability of hinges and tracking systems for security, and always go for multi-point locking.
Installation
Many glazed door specialists offer a supply-and-fit service for the units themselves, which can give you peace of mind that the installation will match your expectations. You’ll probably need to contract your own builders to form any new structural openings. Bear in mind that larger apertures will need a load-bearing lintel above, which will add extra materials and labour costs. Your architect or structural engineer can advise on the right size of lintel.
Frame options
There’s a lot to account for when choosing between the different frame materials for glazed doors, but here’s a quick-fire guide to the main considerations: PVCU is the cheapest upfront and is available in a wide choice of colours, but there’s a huge variance in prices depending on quality. It’s low maintenance, but not as durable as the alternatives; replacing rather than repairing is generally the norm, so lifespan costs may be higher. Timber Engineered softwood products can offer a very good service life and fantastic thermal performance, though they need more maintenance than PVCU and aluminium. Look for products that provide a lengthy warranty on the factory finish (six years is commonplace on stains; longer on paint) to reduce ongoing upkeep. Hardwood options are available, offering the benefit of excellent stability and durability, but are likely to cost anything from 25%-50% more than softwood versions. Aluminium offers strong, slim profiles. These products are ultra-low maintenance thanks to their corrosion resistant powder coatings (available in a wide range of colours), meaning the frame is easy to care for. The metal will not swell, crack, split or warp over time, ensuring an extended product life. Their growing popularity means they’ve become competitive price-wise.