The construction of a Timber structure is becoming increasingly popular as builders start to turn to more sustainable building methods.

It is important to know that, to sustain a large and growing timber frame construction market, Sustainable Forestry Practices are imperative. Thus, buying from a well-trusted, certified supplier ensures that you are buying from a company that acquires its wood from a sustainable source.

A timber structure has some great qualities that make them stand out above other alternatives such as their versatility and high levels of insulation. However, it all comes down to the building methods. In South Africa, a timber structure needs to be correctly designed according to the SANS 10082 regulations to ensure the structure, is safe, strong and durable.

5 Basic things to know about a timber structure

We have gathered some helpful tips about timber building materials used to build a solid timber structure.

1. Deciding on a timber structure type.

Firstly, you should decide what type of timber building type you want. The design process involves a deemed-to-satisfy approach or a rational design approach.  

A deemed-to-satisfy approach refers to the rules and regulations for building a standard timber building while a rational design approach refers to a custom timber building where a structural engineer needs to analyse and approve the design. These timber structures can be used to build either a single-story or multi-story structure.

There are three standard types namely:

Timber frame Buildings

Builders construct this structure entirely out of timber and add insulation between the open spaces of the wood structure. They also use other materials such as mortise and tenon joinery to hold the structure together.The methods and CCA structural timber used to build a timber frame make it solid and durable.

One of the oldest known building methods is timber framing because of the ease of construction and the sturdy and resilient qualities of timber.

Builders commonly use timber frame structures along the coastline because it is one of the main building materials allowed in these areas. It is important to note that all the timber used must undergo CCA treatment.

Log Home Buildings

It is a house built of logs. The logs are generally notched at the ends and laid one upon another to form the house. The spaces are filled with plaster, moss, mortar, mud, or dried manure. 

Log homes are well known for their superior insulating properties. They have a rugged and rustic look which makes them blend well with mother nature.

Cross-laminated Timber Buildings

It is a structure built using an engineered wood product consisting of layers of kiln-dried dimension timber, they are placed at right angles to one another and then glued to form structural panels. By gluing layers of wood at right angles, the panel delivers excellent structural rigidity in both directions. 

It can be used as an alternative to concrete to form the walls, roofs, floors, and ceilings of a building, and is particularly well-suited to multistory taller wood construction.

2. Building a secure foundation.

Before building a foundation, you must first evaluate the (ground) soil conditions. Always look for any weaker areas, and other factors, such as access restrictions, water flows, or other conditions that might impact the foundations.

The type of foundation you choose depends on the soil type, the size of the structure, the roof size and pitch, the cladding mass, and the geographic region.

There are many kinds of foundations, two main types of foundations used are:

A Strip Foundation – You can use this type of foundation is generally shallow and built on relatively flat sites or sites with a gentle slope. They are only suitable for low to medium-rise buildings, such as domestic residential projects, where the underlying ground conditions are very good.

A Planted Pole Foundation – This type of foundation is used on steep, sloping sites as well as on sandy coastal sites. You should not use poles with a diameter of less than 150mm and it must be CCA treated to Hazard class H4.  Before installing the poles, a pre-cast concrete footing with compactable substrate around the pole to stabilize it should be prepared. Do not plant the bottom end of a pole in wet concrete otherwise, it will create a moisture trap at the bottom of the pole where degradation will start.

3. Designing a sturdy floor

A timber floor must be able to handle a lot of traffic and weight without excessive deflection, vibration, and bounciness. To avoid the risk to the structure during periods of high wind load, the structural link between the foundation and the walls must be securely anchored to both the foundations and walls.

There are 2 main types of timber floors in a timber building namely:

Suspended wood floors – Generally, there is an open space between the floor and the foundation.  The main benefit of these floors is that it allows airflow and ventilation. This can prevent mould and dry rot that occur over damp ground.

Properly insulating the floor is highly important because airflow under the floor can cause draughts and cold in the house. For solid insulation, you can use Thermofloor panels.

Plank and Beam floors – This type of framing does not consist of any joists. It consists of widely spanned timber beams. The floor spaces are rectangular. A square layout will prevent many problems, especially in the laying of the finished floor.  Thus, it is important to check for squareness.

You can do this by using a long length measuring tape. The beams play a vital role in helping the bottom of the floor resist lateral loading from wind and other extreme forces.

CCA-treated flooring is mostly preferred by builders who build structures along the coastline. Other suited areas are where termites and moisture are a threat to timber structures.

4. Choosing the correct cladding for your walls.

Timber frames generally have a lower mass than masonry walls. The low mass together with the strength properties of wood is the main reason why timber frame houses often perform much better in earthquakes than other building types.

Cladding, also known as siding, plays an important role in the appearance of the building exterior. It also functions as extra protection from outside elements. you can use cladding for interior and exterior purposes.

You should only use Corrosive-resistant nails to secure the sidings. Examples are copper, brass, stainless steel, galvanized steel, or sherardized steel.

Timber cladding has different shapes, two main kinds of cladding use are:

Half Log Cladding

People generally use it for the exterior of a timber structure. Half log cladding has a curved profile on the front of the timber, which gives it the ‘log’ effect, and it is flat on the back.

You can add a finishing touch to your home by using exterior cladding, which undergoes treatment according to the H3 CCA Treatment Class. You can use it in various places around the house to create a sophisticated finish.

Tongue-and-groove Cladding

You can use interior cladding for interior ceiling. It has natural air pockets in the wood’s grain. Within its cellular structure which retains cold and heat. Furthermore, is has excellent soundproofing and insolation character. This is very important in creating that relaxing environment that timber homes generally offer.

5. Building a solid timber roof structure.

It is vital that you build a roof structure correctly and in accordance with the SABS (South African SANS Bureau of standards) regulations. This is to ensure that it is strong, durable, and safe.

Bracing and anchoring are critical in all roof systems. A roof comes in a triangular-shaped frame, formally known as a roof truss or a flat roof frame.

Designers use a truss to bridge space above a room and provide roof support by designing a structural framework.  By connecting ties and struts to form a structure, they create a large span beam. Trusses usually occur at rectangular intervals. They fix the ceiling to the roof trusses.

Secondary beams usually carry the vertical loads of a flat roof and transfer them to primary beams, which are in turn supported by columns.

For the horizontal wind bracing system, you can use wind bracing straps or timber boards to transfer the horizontal loads down to the foundation. It is crucial to ensure that all water drains off the roof without ponding.

3 important factors to observe in construction.

When designing a timber building, you should keep these 3 important factors in mind:

Moisture and water – Builders should always avoid areas where there is constant still water or build-up water. This is probably the biggest cause of the deterioration of untreated and treated wood.

Wood weathering – Weathering conditions, such as direct sunlight, frost, and moisture cause weathering of exterior wood. However, you can add additional protection to prolong the life of timber products. You can apply sealants or waxes, or building an overhang may also help.

Insulation – Poorly designed wall and flooring systems are often the biggest cause of poor insulation. Timber has great insulation qualities. According to The Woodapp, “…wood is 400 times better than steel and 10 times better than concrete (per volume) in resisting the flow of heat due to its low conductivity. “

 To prevent poor insulation, it is imperative that you build the timber frame the correct way. Thus, you need to design and build in accordance to the SANS 10082 regulations.

Are you ready to build a solid timber structure?

At Sabie Poles, we supply treated and untreated S5 Grade Construction Timber of various sizes. We also supply six different Timber Mouldings (namely Decking, Cladding, Ceiling, Flooring, Architrave, and Quarter-Rounds), and CCA-treated Poles of different lengths and diameters.