There are 5 basic window types: Sliding, Top Hung, Side Hung, Double Hung, Bi-Fold and Louvre. Window and door units are generally called windows by manufacturers in Australia and are available in standard aluminium, architectural aluminium (thicker profile), timber, PVC and combinations (see our Composite Windows & Doors article for examples).
When selecting a window style, consideration should be given to:
- Which one looks best on the outside when opened
- Which opening mechanism works best for the situation i.e. sliding or winding
- How important is their fully opened surface area for ventilation
- The best shape and size considering the wall space
- How much they are exposed to violent weather how good is their weather proofing and are they able to meet Bushfire requirements in your local area - Level 1,2,3 or flame zone
Door hardwhere such as handles and locks usually come with external doors but not always, so check with your window and door supplier.
All aluminium window units are powder coated and will not warp, rot, or distort. They will not rust don't require painting, and will provide years of trouble free operation. However aluminium units being a standard 'Duraloy' powder coat finish will corrode if not maintained to local conditions. The highest powder coat finish is 'Duratech' and is the best suited finish for windows located in highly corrosive locations such as beach front and other highly corrosive environments. Duratech is far more expensive than Duraloy and if the wrong finish is chosen to reduce costs it could mean that the window units will need to be replaced sooner rather than later. Note, the duratech finish does not have the colour range of the Duraloy. See 'windows are not windows' blog
The common belief is that aluminium windows are maintenance free, this is not true. Window units will require hosing down to minimise corrosion damage from salt and corrosive environments and many manufacturers will void warranties if they can prove that windows have not been maintained as per warranty instructions.
While standard aluminium windows are the cheapest and most common style, they are generally the least attractive being too slender in profile. In fact, standard aluminium windows can completely destroy the look of a well designed and constructed house and can reduce its re-sale value accordingly. For that reason standard aluminium frames should be avoided on homes costing more than $500,000, that are architecturally designed or homes that are in a high scenic areas. More recently window and door manufactures are providing a commercial range for residential use the main deference being the window is more robust and has a 'chunkier' profile more like a timber window.
Aluminium windows have, as standard insect screen housing so screens are easy to fit. Screens can be fitted to the inside or outside of the window unit depending on use, window type and bush fire code requirements.
The best colour for frames is usually a mid-range to dark colour that compliments, or relates to the colour of the external cladding. If possible, avoid white standard aluminium frames as they will stand out emphasizing the flimsiness of the units.
Sliding windows & doors
Sliding aluminium window frames slide horizontally (see All Weather Windows for a size chart).
Timber framed horizontal sliding windows are available however they are rather bulky when insect screens are added.
Top Hung Awning Windows
These are hinged at the top and open out to to varying degrees depending on the manufacturer. They are pre-made to standard sizes or made to order, in both timber, and aluminium. Old format awnings provided poor ventilation and no opportuinty for hot air to rise up and out of the window. Todays boutique window unit manufactures are correcting this by designing awnings that allow four sides of the window to ventilate.
Timber framed windows are usually constructed of Western Red Cedar and come generally unfinished. Very few timber windows only doors come in pine core and are laminated with a western red cedar finish.
Top hung awning windows have one of the cleanest looks of all window types, due to the window being one piece of similar size to the sash.
While staining looks very good, natural timber frames need to be re-coated every 2 years. Painted frames require less maintenance.
Side Hung - Casement Windows
Casements can be singles or paired (which are double windows hinged on both vertical sides and open out to about 90 degrees). They ahve a timeless appeal to them and can be opened by a 'friction stay' or a winder and offer excellent ventilation. The old casement opening method used a perforated flat bar system, this old method does not meet current window manufacturing codes. Casements are made in both timber and aluminium.
Double Hung Windows
Double Hung Windows slide vertically up and down and both panels can move independently or just one can move and the other is fixed. They are manufactured in both timber, aluminium and also come in a sashless range www.britts.com.au/sashless.html allowing uninterupted view potential.
The old double hung windows had a great counterweight system that made opening and closing them easy; in addition to which they offered a long life span. New versions sold today generally use a hydraulic system which make the windows heavier in operation and often problematic. If you want the old counterweight windows you will need to shop around because they are not common and will probably be expensive (you may have to have them custom made).
Remember that double hung windows only allow half the window space to be open at one time so they only provide average ventilation.
Bi-fold windows are made in two or more parts and fold back on themselves (in a concertina manner) and stack at one end or both ends of the window frame. They allow the window frame to be completely open, allowing the inside space to connect more with outside spaces. They are great for long wide windows that have dramatic outlooks and can be used as a servery onto a deck area. In a servery situation the window will need to be bottom hung and purchased without a sill so the builder can fit a sill of granite, stone or whatever you think is appropriate for a weatherproof solution . When they are open, they are one of the best windows for ventilation (along with side hung casement windows), however because there is a wide open space, security may be an issue in some environments.
There are strict standards that all manufactures must adhere to when claiming that the windows are weatherproof but it is always recommended that a window overhang be incorporated into the waterproofing system so the unit can be fully utilised during all types of weather.
Louvre windows are available in steel, aluminium or timber and are all "purpose made". They are one of the more modern looking windows and great for ventilation and the blades can be of glass, aluminium or timber. They can be left open at an angle in light rain without an overhang being required.
While they look absolutely fabulous they are not fabulous to clean, in fact they are extreamly difficult and time consuming to maintain. This is amplified by the fact that they use different (laminated) glass than conventional windows which is much harder to clean.
All window and door manufactures have a standard size range in all window types but many manufactures make non-standard shapes and sizes, these cost around 10% more than the closest one in their standard range.
Positioning of windows
The position of windows is often influenced by the layout of the interior. How windows appear on the exterior is perhaps more important, especially for walls fronting the street, because window design and placement can radically affect the attractiveness of a house.
Window sills are generally located either 600mm or 900mm above the finished floor level. 600mm sills will allow optimum furniture arrangement and maximum sun penetration during colder months.
The head height of windows and doors are generally 2040mm above floor level and this is a comfortable standard for most people. If a window or door is too wide or too high it will look odd. Winodws need to work with the design, scale and bulk of the building. Large windows need large walls.
While an aspect of the house may entirely dictate window positions, the following general rules apply:
- Minimise windows and door openings to the west due to the hot afternoon sun and the cold westerly winter winds
- You can not go wrong with big windows on northern elevations with ample window overhangs (of no more than 1400mm). This allows for good all year round sun penetration. If trees are outside less of an otherhang maybe required.
- Favour the eastern side for big windows. The rooms with this aspect will be warm during every season and cool in the afternoons.
- Minimise southern windows because they get little sun penetration and lose a lot of heat during winter.
The Sash (outer) Frame
The Sash Frame consists of the two sides, called jams; the top called the head, and the bottom of the frame called the sill. The sill is often wider than the rest of the frame.
In timber or metal framed houses the windows are fixed into the wall frames and then a lightweight cladding is applied to the stud walls. Any future alterations are easier because the surrounding finish is only a lightweight timber architrave, which is easy to remove.
The brick veneer wall and other masonry claddings are built around the installed windows as well and any later changes will require the surounding brick work to be demolished and patching a brick wall involves more labour and motar is difficult to match.
For masonry houses, the sash frame is likely to be fixed into the masonry by the carpenters when they construct the roof frame.
In either case, when a window is built into the wall, flashing and storm moulds should be fitted into the sill jams and head of the window, and should be slightly exposed to be able to function well as a moisture barrier.
The Window (inner) Frame
Once the roof cladding is finished there is pressure now to get the building to "lock-up" stage, where it can be sealed for weather and security. That means installing windows and doors as soon as possible.
If you are using standard off-the-shelf window units then the installer ideally will need to ensure that the window frame opening has at least a 10mm tolerance (gap) to the stud work.
The quality of standard frames can vary. They are only as good as the corner fixing and this and the general quality of the windows should be checked when your windows arrive on-site. Do not let the truck leave until you have checked them after they have been unloaded. Then if any are damaged during manufacture or transport they can be immediately put back on the truck. If you don't tackle the issue there and then, the lead time on your replacement windows will drag on.
Later, when wall interior cladding is completed, an architrave is fixed. This is an ornamental moulding that is fixed at the sides of the windows (and doors) to cover the joints between the window and the wall lining. There are alternatives to architraves such as shadow lines (neatly plastered 10mm gaps between gyprock and timber door jambs).
For a full description of window and related terms see Stegbar's Glossary.
Glass and glazing
The type, quality and thickness of glass can make a huge difference to the price of windows. There are various types of glass such as reflective, laminated, toughened, double glazed and insulated that can be used in both windows and doors. Each has a different strength, thermal effect, saftey factor and privacy ability. Double glazing is worth considering for cold climates, high busfire areas and noisy environments. Try to stick with standard 6mm glazing where possible and only use non-standard glazing where absolutly nesessary.
The Building Code of Australia stipulates minimum glass thicknesses for different situations but the codes are not readily accessible to the public. Your local council has a copy as do most building professionals.