Casement windows are the most popular type of uPVC windows installed in the UK and are fitted with one or more opening vents (or casements) which open outwards either from the side or from the top.
They are normally combined with fixed panes within the same window frame.
Tilt and Turn uPVC windows open inwards into the room and as the name suggests, can either be tilted inwards or swung (turned) inwards on the hinges, by operating the handle in a different position.
Tilt and turn opening vents can also be combined with fixed panes.
Sliding Sash uPVC windows replicate the traditional vertical sliding wooden windows often seen in Victorian style properties and are probably the most expensive of all uPVC windows.
Sliding sash windows can be fitted with an optional tilt facility to enable the windows to be cleaned from inside.
Bay windows consist of more than one window frame fixed together with reinforced bay poles between them, so that the bay window follows the shape of the supporting brickwork below.
The space created by the curved or rectangular shape of the bay is part of the internal room.
A Bow window, or a plant-on bow as it is properly referred to, also has more than one window frame and projects beyond the external brickwork without being supported by it.
A bow window can replace a flat window and provides a deep internal window sill whereas a bay window does not.
uPVC is the abbreviation of Un-plasticised Polyvinyl Chloride and is exactly the same product as PVCu. In day to day use the terms have become interchangeable but officially PVCu has been used since the late 1980’s, bringing the UK into line with the rest of Europe. This is simply because in most European languages the noun (PVC) is placed before the adjective (unplasticised).
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Polyvinyl Chloride (PVC) is a chemical compound of chlorine, carbon and hydrogen originating naturally from petroleum, natural gas and sodium chloride (common salt).
PVC is commonly used in plastic sports bags and some shoes after being modified by softening it with the addition of plasticisers. Un-plasticised Polyvinyl Chloride means that the product has not been modified and therefore not softened, but in its pure form it is still not entirely suitable for windows and doors.
Stabilisers and additives are required to improve its durability, and ensure that it is UV stable and does not discolour. The amount of these additives differs from one manufacturer to the next to form different compounds, though two common additives are acrylic to harden the compound and Titanium Dioxide to make it appear whiter.
As a result, uPVC Windows: –
• Do not biologically decompose or rot but can be recycled
• Are resistant to weathering
• Are low maintenance
• Are tough on impact
• Retain their shape in normal climate conditions
• uPVC can be reshaped and formed at high temperatures so can be extruded to form window and door profile and even bent to form arched windows
The term ‘uPVC profile’ refers to the cross section (shape or profile) of the various extrusions and there are hundreds of different types of extrusions for uPVC windows and doors.
The more common ones being manufactured by Deceuninck™, Duraflex™, Rehau™, Synseal™, Profile 22™, Network VEKA™, Plastmo™ and Kommerling™.
Each manufacturer has a number of different product ranges to serve both commercial and residential customers and within each range there are individually shaped profiles for uPVC windows and doors.
Breaking it down even further, different shaped extrusions are required for window and door outer frames, sashes, casement vents, door leaves, glazing beads, bay poles, sills, mullions and transoms.
uPVC windows are available in a wide range of colours including 6 different shades of white, woodgrain effects attempting to replicate, mahogany, oak and rosewood among others, and solid colours such as red, blue, black, green and cream. When specifying white uPVC windows it is important that the frames and sills are made from the same compound and therefore are the same shade of white.
O1 is the whitest shade of white but it would be unsatisfactory to fit it onto a creamy coloured white sill. The issue is highlighted when it comes to conservatories as many installers use conservatory roofs and frames from different manufacturers. This could result in the frames being a different colour white to the roof spars – and sometimes a different white again from the sills and trims.
Those uPVC extruders which manufacture their own uPVC profiles for the many types of window and door frame, conservatory roofs, trims and sills are therefore at a distinct advantage as they can offer a colour match across the full range of products.
Add to that all the different types of insulating glass sealed units that are available – clear and obscure, float, toughened and laminated, different thicknesses of glass and widths of sealed unit – and there are an infinite number of combinations, each being more suited to one application than another.
The many different types of decorative glass such as Georgian bar, leaded designs, coloured and bevelled glass add not only to the choice but also to the confusion.
The choice widens even further when conservatories are included in the equation as glass roofs can now include anti-sun and self-cleaning glass, and that doesn’t account for the many types, colours and thicknesses of polycarbonate sheets for conservatory roofs.
One of the many reasons for replacing your existing windows is the excellent safety and security features offered by the very latest advanced PVCu windows.
Old wooden windows generally have 3 mm single glazing fixed into the frame with either putty or an external quadrant bead held in with panel pins.
Even the early PVCu frames offered very little in the way of resistance to potential burglars, with externally glazed windows, poor locking systems and frames without reinforcement.
For the best in safety and security, the latest uPVC windows should all have: –
uPVC casement windows are the most popular type of window installed in homes in the UK.
They are fitted with one or more vents, known as casements, which open outwards either from the side or from the top, often together with fixed panes, all within the same window frame.
Normally, the larger the window and the more opening vents it has, the more expensive they will be.
PVCu casement windows in a woodgrain effect finish or ones with coloured window frames and decorative glass will be more expensive than plain white windows.
For the record, uPVC is the same as PVCu!
uPVC Casement windows – Friction stay hinges
Whether opening from the top or the side, uPVC casement windows are fitted with metal friction stay hinges which means that when the sash is fully open it dissects the opening in two, rather than being hinged from one side, like a door.
Different types of friction stay hinges can be fitted.
Some friction stay hinges on uPVC casement windows can provide almost full width fire escapes whilst others enable the outside of the window to be cleaned from inside. These are referred to as a fire egress stay and easy clean hinges.
uPVC casement windows – Key locking handles with night vents
Key locking handles generally include a night vent function, allowing the opening section of the window to be locked in a slightly open position.
A wide range of locking systems are available, including cockspur handles which are not very secure. Espagnolette handles however, are excellent, especially those fitted with multi-point locking in the form of shoot bolts and hook bolts.
uPVC Casement Windows – White or Woodgrain Effect or Coloured?
Although the vast majority of uPVC casement windows installed in homes in the UK have white frames inside and outside, they are available in a wide range of wood effect finishes and solid colours.
Coloured uPVC casement windows are available and include red, blue and green uPVC frames, often with white frames on the inside.
Woodgrain effect uPVC casement windows tend to have either woodgrain effect on both sides or on just the outside.
The advantage of having woodgrain effect windows which are white on the inside is to keep internal rooms brighter.
As the name suggests, uPVC tilt & turn windows can be tilted inwards or swung (turned) inwards on the hinges, by operating the handle in a different position. They were originally designed in Germany for high rise flats so that the windows could be cleaned from inside.
uPVC tilt & turn windows offer lots of ventilation and are ideal for conservatories, particularly if they are south or west facing and would otherwise get too hot inside.
uPVC tilt & turn windows do however have some disadvantages as they tend to have wider frames to accommodate the complex operating systems and locking mechanisms.
You also need to be aware that obstructions such as furniture and taps in a bathroom or kitchen can restrict their usage and the large openings can be dangerous in a child’s bedroom for example, although they do offer excellent fire escapes.
Benefits of uPVC Tilt & Turn Windows
uPVC tilt & turn windows are more expensive than uPVC casement windows because they take longer to manufacture, have more expensive operating systems & locking mechanisms and not least because the uPVC profile, being wider, is more expensive to produce.
Nevertheless, in conservatories they have some advantages over uPVC casement windows.
Firstly, they are stronger than casement windows due to their wider frames, tilt & turn windows can be manufactured in larger sizes than casement windows. Consequently, for a given size of conservatory you may need fewer (but larger) windows if you choose uPVC tilt & turn windows.
Also, since the expensive part of uPVC windows are the opening sections and they have much larger opening sections than uPVC casement windows. However, you will probably need fewer opening vents if you choose uPVC tilt & turn windows.
Another, major advantage they have, particularly when used in conservatories, is the lack of a transom bar (the one that is normally at eye level when you choose uPVC casement windows) which provides a better view out of the conservatory into your garden.
uPVC sliding sash windows which replicate the traditional vertical sliding wooden windows often seen in Victorian style properties are probably the most expensive of all PVCu windows.
They are also expensive to install, as any existing box sashes (containing the weights and cords which operated the original wooden sliding windows) normally have to be removed and the internal reveals made good.
Nevertheless, in the right sort of property there is no substitute.
uPVC sliding sash windows with a tilt facility
uPVC sliding sash windows can also be manufactured to incorporate a tilt facility.
This can apply to either one or both of the sliding sashes and allows cleaning of the outside of the windows from inside your home.
The tilt and slide action also provides an excellent fire escape.
As with all styles of uPVC windows however, the more sections of the window which open, the more expensive they will be.
uPVC sliding sash windows in Orangeries
Traditional orangeries are manufactured with hardwood frames and if fitted with timber sliding sash windows are generally of excellent quality, however with quality comes a hefty price.
uPVC orangeries becoming increasingly popular and where they are fitted with uPVC sliding sash windows they attempt replicate windows from the Victorian era.
uPVC orangeries are generally less expensive than hardwood orangeries but they can still be fitted with sliding sash windows.
uPVC sliding sash windows in listed buildings and conservation areas
uPVC sliding sash windows are only normally appropriate when replacing existing wooden sash windows, in order to maintain a similar appearance to the originals.
In some situations, such as listed buildings and in conservation areas, rules will not permit the use of uPVC and only timber windows can be installed. This has resulted in a market for the repair of old wooden sash windows where new sections of timber are spliced in to replace rotten parts and the replacement of worn out cords and weights.
However, modern uPVC sliding sash windows replicate early Victorian wooden versions so well that on occasion they are permitted to be installed in older properties.
Curved and rectangular uPVC bay & bow windows have reinforced poles between each individual window for strength and support. A curved uPVC bay or bow window would normally have round bay poles between the sections and a square or rectangular uPVC bay or bow would have a square bay post on the corners.
FENSA and Building Regulations rules apply to all replacement windows but in the case of uPVC bay & bow windows additional rules apply to the structural support which they must be fitted with and the way in which old bays and bows are removed to be replaced with new uPVC bay & bow windows.
Square or rectangular uPVC bay & bow windows are usually in three sections but they also can be made up of just a front and one side; this is referred to as a dog-leg bay.
uPVC Bay Windows
A uPVC bay window is generally one where the windows follow the shape of the supporting brickwork below and the space created by the curved or rectangular shape of the bay is part of the internal room.
Curved bay windows, generally in five sections, were originally built on Victorian properties as a sign of wealth.
uPVC bay windows are normally replacements of original wooden bay windows and the use of round bay poles allows several individual windows to be fixed together to form the bay.
One point for homeowners to be aware of is offers made by window companies for, say 5 windows for £????. A curved uPVC bay window with five sections will always count as five separate windows for the purposes of a quotation.
uPVC Bow Windows
A bow window or a plant-on bow window as it is properly referred to, projects beyond the external brickwork without being supported by it. A bow window generally provides a deep internal window sill whereas a bay window does not.
uPVC bay windows are often conversions from original flat windows, where the householder has decided to convert a flat window into something more visually appealing. If a flat window is converted to a bow window, the width of the original flat window will normally determine the number of sections the new bow window will have.
A flat window at 1.8 metres wide would normally be converted into a three part bow window and a flat window at 2.4 metres wide would normally be converted into a four part bow window.
When removing a flat window and installing a uPVC bay window it is important that the new roof and base of the bow window is properly insulated to conform with Building Regulations with regard to heat loss.
