Guide to Patio Door Types - part 2: Frames

from  ezine articles / Bee Primrose

Traditional or modern? Classic or contemporary? We continue the article describing types of patio doors, to provide an informative guide.

part 2: Frame Styles - timber, metal, pvc, composite, frameless, profiles and sight lines. 

Patio doors comprise an outer frame plus individual door frames. These can be made from wood (soft- and/or hard-wood), metal or alloys (usually aluminium), pvc (polyvinyl chloride, a thermo-plastic polymer - the 'u' stands for unplasticised) or a composite material, which may comprise any of the foregoing materials plus grp (glass reinforced polymer). There is also a style known as frameless, where the vertical sides of each door have no frames.

Generally, timber frames are considered more traditional and can look beautiful! Hard wood such as oak is, as the name suggests, far more hard-wearing than a soft wood such as pine. Weather, especially strong sun, can take its toll on timber frames which could need to be varnished or painted annually. Wooden frames can swell and shrink with humidity, therefore opening and closing doors can require force and gaps can allow draughts in colder temperatures.

Metal frames, usually aluminium, provide strength in compact form. As notoriously good conductors (which is a bad attribute for insulation), frames made from aluminium are thermally-broken, which is a good attribute. It means that the metals on the inside and outside of the door frames are not joined, preventing the temperatures from being transferred between them. A bare metal frame would look completely unattractive so it is powder-coated in a choice of over 100 standard colours, including a white that resembles pvc.

As with timber, the quality of pvc frames available can vary - and generally, you get what you pay for. The better ones will usually be reinforced with metal, internally, for greater strength but the cheaper options can be a nightmare to live with - sticking, twisting, splitting, discolouring, warping - often within a very short time. Most usually supplied as white, some manufacturers offer limited colour options or wood effect finishes.

Generally stronger than pvc, composite patio door frames vary with each manufacturer, offering a variety of finishes.

Whilst frameless doors have no side frames, the top and bottom of each door requires a mechanism, typically presented in aluminium, to allow it to slide within the top and bottom guides. Frameless glass doors have the best sight lines.

Sight lines is the term used to describe the interruptions in the view through the doors; in other words, the width of the vertical opaque areas between the glass when the doors are closed. On hinged doors, such as French doors and bi folding doors, timber and pvc frames generally have broad sight lines because, unlike aluminium, narrower frames would not be strong enough to be fit for purpose. As a guide to the width of two frames together, cheaper pvc door frames can exceed 200mm, aluminium frames are typically between 135mm and 160mm and frameless patio doors sight lines are under 40mm. Depending on the width of each door and number of doors to be installed, the difference in glass to frame ratio could be significant.

Door profiles - the width of the visible door edges when open - may be a consideration. Additionally, some door profiles are ugly, showing mullions or working parts that would be better hidden from view.

SunSeeker Doors is the only UK company to manufacture and install a choice of slide and pivot doors (including frameless glass doors), bi folding doors and French doors.

Article Source: Guide to Patio Door Types