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Theme: doors and windows

Maintenance and meeting Part L have driven the development of doors and windows in recent years. The quest for most materials is to mimic the timber they replace while pushing for greater demands for security and soundproofing There has been no fundamental change in doors and windows recently. There have, of course, been long-term changes, for instance from ply or hardboard-faced flush doors to PVCu, pressed composition board, steel and, if the pundits are correct, increasingly to GRP doors. Many of the domestic variants, even PVCu doors, have surface treatments that simulate timber - even though the ultimate for domestic timber doors has been to give them such a high-gloss smooth finish that they effectively resemble plastic. The trend in domestic windows is also in the direction of imitating timber. Here, until the introduction of powder coating, steel was the poor relation, aluminium deemed too industrial and PVCu was the crude white interloper. In the domestic world PVCu now seems to reign supreme, particularly since its profiles have diminished with the help of steel reinforcement and the introduction of simulated timber finishes.

On the commercial front, the trend to unitised walling systems incorporating integrated opening lights and ground-floor doors continues - especially in the citycentre locations where access is especially constrained and where speedy installation is a necessity. For other locations, many architects believe that stick-constructed curtain walling is somehow of a lesser quality than unitised. It is a view that seems to be based on theory rather than experience.

Even when a walling system has standard integrated doors and windows, it may be necessary to bring in specialists for specific needs - such as at the London IMAX cinema where doors had to cope with regular automatic opening and closing plus infrequent, short-time but massive use.

Unchanging change Two years ago the government introduced a rule that replacement windows and glazed doors had to be fitted by a registered installer or have formal building regulations approval and thus conform to the same standards as new building. That was to plug a regulatory loophole in the general move to reducing CO 2 emissions via construction.

Now looming larger for everyone are the mooted 2005 changes in Part L of the building regulations. Over the years, with every improvement in the standards enshrined in Part L, sections of the industry have wrung their hands and predicted the end of construction as they knew it. It is difficult to be sympathetic, because everybody knows it is national and Europe-wide policy to improve greatly the energy performance of buildings, and hence that the standards demanded of builders will always increase. And since changes are always heralded years before they are implemented, everybody has time to develop strategies whether in improving the inherent thermal performance of their products, or in working out combinations of materials that will satisfy the standards proposed for next year. Changes are promised not to occur for a further five years, but the next revision of Part L in 2010 will certainly represent a further tightening of standards.

Secured by Design (SBD) is not so much a standard but a very good idea. A not-forprofit company set up in 1999 by the various Associations of Chief Police Officers, it issues licences to companies whose products meet quite tough standards for security. A quick trawl thorough the list of current licensees suggests most are door and window manufacturers. So it looks as if the industry thinks it a good idea as well. SBD also gives awards for approved new housing developments.

Matching materials and maintenance The Holy Grail in construction is zero maintenance. More realistic is the hope of less maintenance. But that does not stop enterprising manufacturers from trying. PVCu seemed to offer low maintenance, but it had an early rough run with accusations of poor fabrication, yellowing of the predominantly white colour, and profiles that had to be heftier than timber for structural reasons.

This was especially noticeable when PVCu was used for replacement windows.

Now the old stigmas have faded. With steel reinforcement, the size of profiles can be brought down to much the same as for timber - so much so that a number of firms now offer PVCu windows with a simulated timber grain.

Born again timber A recent alternative to both PVCu and timber is Fibrex. It comes from Andersen Windows, which claims to be the biggest wood window manufacturer in the world.

Fibrex is a composite material made from reclaimed pine wood fibres bonded with a thermoplastic polymer. It has the strength, thermal and stability performances of timber, with a texture and appearance to match. But the polymer coating is resistant to flaking, blistering, cracking and peeling like PVCu, and offers the same white internal and timber external face. This comes in pine, oak and maple, plus a range of plain colours including a natural beige, an earth colour known as Terratone, and forest green.

Where it scores over PVCu windows, says Andersen, is that is has mortise and tenonstyle joints, not welded. If you can't find the size you want from the 99 standard designs Andersen offers in this Woodwright range, there is a made-to-measure service.

Mix not match Some 50 years since it first started out in business, Mumford & Wood has followed the current fashion for having one material outside and another inside, on its window.

Maybe it is something to do with the fact that there has to be some kind of thermal insulation between the inner and outer face that legitimises this modest deception.

Whereas wood outside and plain white inside is a common combination, Mumford & Wood has gone for wood with external aluminium beads and natural wood inside, and all-aluminium outside. It is called the Contemporary range and the timber options are pine, mahogany and oak. Exterior aluminium components are polyester powder coated in a choice of standard colours.

Window on tradition Crittall has been a name for Modernist architects to conjure with since the 1930s. True to its heritage, the company is still producing, among other things, steel windows. Now the Crittall Corporate 2000 range meets current Part L regulations with U-values of 1.9 for fixed lights and 2.2 for opening lights. The new range is a hot-rolled steel window that can take glazing systems up to 29mm thick in its overall 40mm front-to-back depth. At the same time, the company has launched the Homelight L, which has slender sightlines and good acoustic and thermal performance. Homelight L comes with a 4mm clear float glass outer pane, a 16mm argon-filled cavity and a 4mm Softcoat Low E float glass inner pane. The steel is hot-dipped galvanised and polyester powder coated.

On the slide During the past couple of decades, there has been a scarcity of horizontally sliding windows. Maybe it is fashion, maybe it is because of the need for sliding gear, maybe it is because early versions were not easy to keep weathertight or secure. Now Architectonics has added a new severe weather performance window/door with a variety of options for all-sliding panels fitting into an aperture up to 6.3m wide and 2.4m high.

The new windows have a polyamide thermal barrier and conform to the coming Part L standards. Gloss white and mill finish are the standard finishes, but a full range of metallic paints is available as are different inside-outside colours.

Tilting at giants A short trip down the Thames, up the Clyde or along any of our big city riversides reveals the prevalence and popularity of luxury apartments. Quite a number of them are luxury apartments with balconies. So Kawneer has added the not-easy-to-remember AA 603 Tilt Slide Door to its 600 Series window and door system. Apparently luxury owners want external access to their apartments and, also want to be able to lock doors from the outside, as well as inside. So the new 603 has a long lever handle that points downward when it is closed. A nice feature is a track filler that clips over the bottom track during building to stop debris from gumming up the sliding works The 'tilt' part of the name refers to the fact that the doors can tilt part open for ventilation. The sliding part is to do with the way they open: you can have them as single and double panels, either sliding or fixed. Other features prevent being locked out: spring-loaded buffers, multi-point locking, anti-slam devices and the like.

For lighter-weight glass doors, there is the MAB top-hung sliding glass door system. Its code number, SD 60-100, refers to the fact that the sliding glass doors can weigh between 60 and 100kg. Not so explicit is the fact that there is a maximum height of 3m - just right for upmarket houses (en suite and shower doors provide an obvious application) and most commercial settings involving glass partitioning. The sliding gear is simple and allows 10mm height adjustment. It will cope with glass (and of course any board) from between 8mm to 12mm thickness. Track profiles come pre-drilled, and there is a small number of accessories.

A similar aluminium sliding system has been designed by architect Allford Hall Monaghan Morris and manufactured by Yorkon for Technal. The latter has named it the GXi and has installed it on a Peabody Trust development in London's Stoke Newington. The double-glazed balcony slider has 41mm sight lines, a 9mm flush polyamide thermal break and the option of flat-faced or curved-face profiles. The GXi complements Technal's FXi46 range of windows, which can be used with curtain walling and with masonry walling.

Because sliding glass doors are supported along their base and only move in a guided single direction, there is a tendency to feel less comfortable with glass doors that swing.

It is an illusion, though, because tempering and toughening processes can make glass a very robust material. The James Price Group has developed Tuff-X frameless glass privacy doors. Made from 10mm thick toughened glass, the doors were heat-soaked, tested, screen printed, and given Manet stainless steel handles and pivots from Dorma. The company offers a full CAD service.

Natural comforts It is sometimes appropriate, in instances such as refurbishment work, to install reproduction period doors. In England that often means using fielded and panelled pine doors - which originally were usually grained to give them the appearance of more expensive timber. In some cases glass replaces the upper pair of panels. Now JB Kind has developed an ingenious system of slotting glass in from the top on one of its four panel ranges, the Premier Pine Collection. This means that the glass and its decorations may be changed around at will. The company also produces a heavy-duty internal plywood flush door with a slatted pine timber core.

Vicaima is a long-established Portuguese timber door manufacturer that has been selling its products in the UK since 1955.

There are three major ranges - the Essential, Classic and Exclusive - and most can be produced as fire-check doors . There are some slightly exotic styles in the Essential Natur and Exclusive Natur ranges, although the Essential Easyclean range is plain and flush.

Timber has its virtues for domestic front doors, but Irish firm New World Development has made doors from PVCu for some years. Now it also makes them from GRP with aluminium reinforcement and a polystyrene infill. There is a perceived market movement towards the use of GRP, fuelled, says the company, by a concern for heightened security and improved weatherability.

It reckons that within five years, 80 per cent of its output will be in GRP. The new Apeer door, as it is known, comes in eight styles and in door sets. Glazed doors have triple panes and original glass designs by the in-house team. Colours are the primaries, white, black, mahogany and light oak, and the texture of timber is embedded in the GRP - although the doors are billed as wood-free.

Therma-tru has been using GRP in the UK for the past 15 years. Currently it cites a recent Zurich Insurance report, which says that top of the list of reasons for calling back housebuilders, is badly fitted external doors.

Therma-tru argues that timber is nice but it warps and twists and expands and contracts, and that its own fibreglass doors are a better bet. It now makes and assembles door blanks made from GRP blanks made in the US.

Something special Most doors are rectangular slabs of wood, or steel or plastic, which sometimes slide but are mostly hinged on one side and fit into a doorframe. But in public buildings, doors often serve more than the simple function of closing off one cellular space from another.

At London's Imax cinema, a circular glass drum in the middle of a big traffic roundabout beside Waterloo Station, Brian Avery's practice specified large automatic entrance doors. Because the rest of the building was glass, the doors had to be as well. They also had to be capable of meeting disabled access rules and of dealing with the rush of people coming away from a performance. So Tormax produced a set of big automatic sliding doors made from curved glass to match the building's curve. They are of 12mm plate glass and each leaf weighs around 90kg. This weight calls for beefy opening mechanisms - the Tormax XTP operators.

Curtain walling Fenster is the German for window and MagHansen's Hansen Fenster is a Danish system that is claimed to take minimalist design to the limits of performance. The system has neat sightlines and comes in a variety of configurations and finishes. The manufacturer particularly prides itself on the standard vents which may tilt and turn, be top-, side- or bottom-hung and can, in the form of the Hansen Lightline, be a concealed, silicon bonded element integrated into fixed glazing.

Blanketing out sound Building regs are quite good on the issue of soundproofing the walls of bathrooms and WCs, but less good with doors. Now TDSL has launched a range of door sets with good acoustic, fire and mechanical performance.

Sound reductions are claimed to be between 28dB and 44dB - the latter performance being that of the 30 minute fire-resistant Audiospec 41 range. TDSL's existing Timbmet and Firespec ranges - and the Audiospec - are used in places such as Wolverhampton University and BBC Mailbox, Birmingham.

Interestingly, although you might want to see through a door, you don't want to hear through them, and all the doors in these ranges were tested in single- and double-leaf formats and as glazed assemblies.

Soft on the skin Window frames represent an interesting challenge because they are the complicated bit: how to create thermal breaks without compromising security and structural stability and the integrity of closure. Glass, these days always double paned, looks straightforward in comparison. Not quite so straightforward is the variety of coating technologies for improving the performance of glass. Andersen Windows has gone for soft-coated glazing. Its low emissivity argon-filled double glazed units are coated using a sputtering process rather than hardcoated using pyrolitic technology. Andersen claims this delivers lower solar gain than the hard technique, with the result that ultra violet light penetration is reduced and Uvalues get down to 1.4. Equally important for house owners is that this technology allows a high level of optical clarity because there is less likelihood of tinting, colour haze or the delightfully named pyjama striping which can come with conventional coatings.

Bright and layered Laminated glass is interesting in its specialist applications, but in the hands of Vanceva Design it becomes a vehicle for artwork. Architect Featherstone Associates has used it for a hairdresser in London's Soho. A simple pink all-glass shop front is punctuated by a floating mirror that serves as the shop's sign.

Will Alsop's team in Rotterdam has also used the material in its Media Markt building at the Almere entertainment centre. The practice spent a lot of time working out combinations of coloured interlayers, and ended up with a three-layer system. Vanceva's speciality is the intensity of its colours, and new colours have been launched, one a deep red, another a true vivid blue and several versions of white. The interlayers also come in metallic colours and in three textures: honeycomb, linen and sandstone. It is possible to combine all the colours, textures and patterns in the same composition.

Gumming up Fixing windows used to be a matter of wedges and mortar and some sealant. These days, window fitters establish the exact position of window frames in a wall and use fixing foam to provide a permanent seating. Fischer has introduced a two-part polyurethane foam in a 150ml cartridge. The company claims that just six foam dabs around the window, or doorframe are all that is needed - a drying time of 12 minutes allows final adjustments.

Shooting the breeze Trickle vents were introduced, it is said, as a consequence of the increasing airtightness of buildings due to better window design, manufacture and fitting. These may still be no more than long slots carved into the window frame and faced with a grille or a kind of escutcheon. More integrated and visually sophisticated solutions work on the crude principle of making sure the window doesn't entirely close shut at the top - usually by incorporating a permanent built-in slot in the window head. It is possible to specify particular vents before windows are fabricated, and Titon is offering a new range of vents in its Maxiglaze range, called Omniglaze. This is suitable for PVCu, timber and aluminium windows. One of its virtues is an external storm flap which can incorporate a secondary closure mechanism for weathertightness in exposed conditions.

Wagner offers a similar solution, with the 35mm-high vent fixed to the top of the window frame prior to installation.

Reminiscent of the legendary Hõfele catalogue is the 200-page thick Product Directory showcasing Wagner's 2004-2005 aluminium windows and doors. It includes locks, handles, hinges, window gear, vents and architectural ironmongery.

Finding out Window and door manufacturer Jeld-Wen UK now has a drag-and-drop library system of intelligent 3D images of the company's joinery products. It uses the AutoDesk I-drop system, which allows the specifier to browse, select the window or door on its website and drop it directly into their drawing where a gap has been created for it automatically in the AutoCAD drawing.

Just in case the message of double-glazing has failed to convince, the Energy Saving Trust (EST) guide Benefits of Best Practice, Windows outlines the economic and other benefits of double glazing. Other EST publications and programmes are devoted to reducing the effect of climate change by decreasing CO 2 produced by housing-related energy consumption in the UK.

READER ENQUIRIES Andersen Windows 1400 Apeer CD 1401 Architectonics 1402 Birtloy Building Products 1403 CAP 1404 Luform 1405 Crittall 1406 Dorma 1407 Energy Saving Trust 1408 Fischer 1409 Hõfele 1410 Hansen Fenster 1411 James Price Group 1412 JB Kind 1413 Jeld-Wen UK 1414 Kawneer 1415 LB Plastics 1416 MAB 1417 Mumford & Wood 1418 New World Development 1419 TDSL 1420 Technal 1421 The Real Door Company 1422 Therma-tru 1423 Titon 1424 Tormax 1425 Vanceva Design 1426 Vicaima 1427 Wagner 1428 Wright Joinery 1429 Enquire at www. ajplus. co. uk

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