This article was updated on the 7th February 2019.
A number of common building elements are used in different types of buildings. Each aspect has areas that must demonstrate performance. These elements include framing, flooring, species selection, stairs, paneling, joinery, cabinetry, external cladding, decking, and pergolas.
Framing elements are structural members that form the shape of the building. They are generally hidden behind the internal and external cladding and would only be seen during construction. Framing is used for walls, ceilings, floors, roofs, partitions. They generally have small to medium spans and carry light loads. Framing typically employs a number of closely spaced parallel elements to support large areas of lining or cladding.
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- Rafter – supports the battens and ultimately the roofing, and acts as a beam
- Ceiling joist – supports the weight of the ceiling and serves as a beam
- Ceiling battens
- Hanging beam
- Top wall plate – carries roof loads to walls and acts as a beam
- Studs – carry roof loads in axial compression and lateral wind loads.
- Bottom wall plate – carries all loads to the floor
- Floor bearer – carries floor loads from flooring through the joists
- Floor joist - carries floor loads from flooring and acts as a beam
Floorings are primarily appearance graded products with a hardness requirement that many other timber components do not have. Timber flooring is also suitable in applications where cleanliness, weight, and resistance to high point or impact loads is a significant factor.
Timber floors are suitable for a broad range of applications, including shops, restaurants, offices, libraries, houses, sports halls, warehouses, and workshops. Their key features are the following:
- Aesthetically pleasing
- Low maintenance
- Readily available
- High strength to weight ration
- Good sub-floor for carpets and tiles
- Good in-place strength
There are a large number of species or species groups suitable for use in flooring applications. Obtaining accurate information on strength groups, densities, hardness, wearability, and the color is vital to ensure the correct selection of the most suitable species for the application.
Timber floors come in many forms, including solid tongue and groove, parquetry, plywood, floating floors, laminated floors, and a range of proprietary profiles and systems. They can be laid over concrete, particleboard and engineered timber products. Staples and adhesives are commonly-used for fixing.
Timber flooring is primarily an appearance graded product but has a hardness requirement that many other timber components do not have. This is to prevent scuffing, scratching, and gouging during regular use. During installation, it is essential that the moisture content of the timber matches with the anticipated service environment. Floorboards should be fixed to enable some swelling to take place without damage, and an appropriately flexible seal coat should be chosen.
To ensure that timber floors provide satisfactory long-term performance, it is essential that the right floor is selected. It should be installed, finished and maintained following best practice recommendations which could be acquired from manufacturers. Meanwhile, installation and finishing practices must be appropriately selected to accommodate changes in moisture content in the environment that may be caused by changing humidity, air conditioning, heating, exposure to sunlight, wind, rain, etc.
The manufacture of timber flooring is a complex and rigidly controlled process. Each stage of the production process—from the sawing, pre-seasoning, kiln drying, equalizing and reconditioning, profiling, end-matching, grading, and final packaging and storage - must be controlled. This process would usually take six months.
Timber Strip flooring
Timber flooring is a material that is sensitive to weather and environmental changes. These events would cause boards to shrink or swell. Therefore, the correct specification, handling, and installation of timber strip flooring are essential to ensure optimal product performance. In installing timber strip flooring, the following is substantial:
- Fix floors using the correct fixings and materials.
- Only use a professional floor sander and finisher.
- Allow future shrinkage or expansion during the time of installation.
- Ensure that floors are completely dry during installation.
These are structural members that must carry loads of people ascending, descending, leaning on rails, or sitting on rails. Because they are usually on display and are held, stairs often have specific visual and surface finish requirements.
Stairs have a nomenclature of their own, and often the timber selected for use in stairs and balconies has a number of different performance considerations.
- Timber stair treads that are used as fire exits may be required to utilize high-density timber for resistance to abrasion, fire resistance, and strength. They are structural members, and though the top is covered in carpet, the bottom of the stair treads is exposed.
- Stringers are larger members that support the stair treads and have requirements for surface finish and structural performance.
- The balustrade is the paneling underneath the handrails that must stop people from falling through. It must possess good appearance on both surfaces.
- Balusters are vertical members between the plywood paneling that support the handrail. Structural requirements include the ability to carry the weight of people leaning or falling against the balustrade. Straight-grained, furniture quality timber is often specified for these members.
- The handrail will also have to perform a structural function, and the curving of the timber required in the fabrication of the handrail will require it to have as straight a grain as possible.
Panels are used in lining walls or ceilings. These usually have no structural performance requirements. Paneling can be made from board-type products such as plywood, or tongue and groove or lapped timber pieces. Wood paneling may be used as wall or ceiling linings or for built-in features and furniture. A range of timber products can be assembled into walls or ceilings and may feature exposed timber linings.
In most cases, decorative board paneling that is used internally would not be structural. An internal grade would be more appropriate. Only one surface is exposed to view and must have appearance grading. In cases where enhanced acoustic performance is required, small holes can be drilled on a regular grid.
Decorative board paneling used externally is often exposed to varying weather conditions. The glues used must be weather-resistant, and an exterior grade of plywood must be specified. The protective coating on these panels must be much more robust than those used on the inside of the building. It will also require a much shorter maintenance cycle than timber used indoors.
Plywood paneling, particle boards, or OSB boards may be used in either application. With a veneered product, the timber grain and color can be preserved. The texture and appearance of particle boards or OSB can also be used as a feature.
Solid Wood Paneling
Sawn and dressed timber pieces can be laid horizontally, vertically, or diagonally to cover large surfaces. They can be nailed to a frame or glued directly to another surface.
It is also important to have adequate ventilation of the paneling in floor systems. In addition, moisture content must be in equilibrium with the installed environment prior to fixing. This is done to limit the damage caused by shrinkage or swelling in service.
This includes internal fittings such as doors and windows, and their frames, skirtings, or architraves. The joinery has always been a stronghold of timber, but now there are other materials commonly used in door frames and windows.
Timber joinery adds a particular finish to buildings. Generally, it is available in “paint grade” which may be a composite material such as MDF or glulam, or in “clear finish grade” which is generally more expensive and appearance graded products, with dimensional stability and surface finish requirements.
This includes cupboards, benches, and built-in furniture. Many of the same products used in joinery could also be used in cabinetry. Similar to a joiner, paint or clear finish grade materials may be utilized; however, whenever a clear finish is specified, the appearance and surface finish of timber is critical.
External cladding is an exterior grade material. The availability of a wide range of timber cladding products provides designers with many possibilities. For example, timber clad buildings may be designed to suit any environment and fit any site with minimal costing. Appropriate protective coating systems are required to prevent deterioration of timber surface from exposure to the weather. Cladding should be considered an integral part of the overall building design as it can contribute to aesthetics, comfort, and structural adequacy.
Modern finishes give a long lasting and attractive appearance to timber cladding. They could also be used to change the color and style of a timber-clad building. The natural resilience of timber gives built-in flexibility, which helps minimize damage under stresses and strains caused by foundation movement, windstorms, or seismic movement. Timber clad buildings offer excellent thermal performance all year round, and its natural sound damping properties also reduce noise transmission. Obtaining the best performance depends on good design, proper construction practice, and correct installation.
A wide variety of cladding products are available in the market, including solid timber boards in a range of profiles and species, timber shingles or shakes, and various types of plywood and exterior-grade hardboard in plane or surface-textured sheets or planks.
The following factors must be considered in selecting the most appropriate type of cladding:
- Appearance required to suit architectural style
- Availability and cost
- Ease of installation and maintenance
- Prevailing climate and thermal performance required
- Structural performance and strength requirements
- Local government regulations or statutory requirements
- Appropriate sarking, flashing and vapor barriers
Decking is a product with both appearance and structural performance requirements. Attention to detail during installation, initial protective coating systems, and maintenance is essential. It differs from flooring in that each decking board functions independently. Decking may have higher structural performance requirements than tongue and groove flooring that is used in the same application.
Timber decking is an attractive, economical and durable material that is popular for use in domestic, recreational, industrial and marine structures including outdoor decks or alfresco areas, marinas, wharves, bridges, footbridges, loading docks, commercial or industrial decks, grandstands, and tourist projects.
Decking is available for both unseasoned and seasoned timber in a wide range of species, grades, and sizes. External decks must be able to cope with wear and tear from use and to discharge rainwater effectively. A non-slip surface will also be necessary. Rounded corners (arrises) to the decking will help the water run-off. Meanwhile, spacing and ventilation between the decking will prevent water ponding on the deck, but in doing so, the joists that support the decking will require protection from the elements. This process can effectively be achieved by using a protective film over the top of the joists under the exposed decking.
Designers should also consider the following when specifying timber for decking products:
- Preservative treatment
- Moisture content
- Fasteners and joint detailing
- Maintenance requirements
Pergolas and horticultural timber are used in an exposed and often aggressive environment. Treated or naturally durable timber must be used in such a set-up. Wherever possible, ground contact should be minimized by using a steel bracket below ground and bolting to the pergola above ground. A minimum of H4 treatment is required when the timber is in ground contact. In addition, using light-colored surface coatings can lessen the degradation under sunlight and varying weather conditions.