Self-Build & Timber Construction

Timber is one of the most sustainable mainstream construction materials currently available. It is also a relatively forgiving material,  making it a great choice for self-builders considering undertaking much of the construction work themselves. While the use of timber structures for houses appears to be increasing, it remains fairly limited within the residential sector.  This article  explores why and gives an overview of some types, advantages and disadvantages of timber construction. 

An interior with structural timber visible

Historically, timber was the material of choice for domestic construction in the UK. However, over time, the use of timber dwindled in favour of masonry. Elsewhere, timber remains the primary choice of material for residential structures – notably in North America. There, the ready supply of suitable timber means timber buildings can be constructed quickly and economically. The UK however, imports around 80% of its timber.

In England timber houses remain the minority in new build construction. In large part, this is due to limited mortgage options available for homes deemed to be “non-standard” construction. Never the less, the sustainability credentials alone make timber a material  considering for your build. Read on to learn more about some of the types of timber structure available and the advantages and disadvantages.

Types

There are a broad range of timber construction methods, most with long-established histories. Here we give an overview of some key variables.

Post and beam vs timber frame
Post and beam construction is a method that comprises vertical posts and horizontal beams that carry all of the loads. Walls are used to enclose the spaces but are not structural, making this method well suited to open plan spaces.

Timber frame construction refers to a panelised  system of structural walls and floors constructed from timber studs, typically clad with board products.

Soft wood vs hardwood
Hardwood comes from deciduous trees where as softwood comes from conifers. Deciduous trees tend to be slower growing, meaning the wood is usually denser. Consequently, hardwood is generally stronger than softwood. However, due to the length of time it takes for deciduous trees to meet maturity, the supply of hardwood from sustainable, well managed sources is becoming increasingly limited.

Traditionally, hardwoods were used in timber construction; primarily oak and elm. From the 18th century onwards, imported softwoods were increasingly used in timber frame systems. Today, the introduction of engineered products, such as glulam, mean softwood is also an option for post and beam construction.

On site vs off site
Timber systems can either be constructed completely on site, with every piece cut and fixed in-situ or; they can be manufactured off site, with preassembled components bought to site and slotted into place. Prefabricated systems tend to be higher precision and can allow a much quicker construction process on site.

Many timber based systems have been developed to cater to those who intend to undertake the construction of their homes themselves. These include systems intended to be constructed entirely in-situ (The Segal Method) as well as those that incorporate some prefabricated elements (WikiHouse, U-Build).

The Segal Method: 1-Foundations; 2-Structural frame; 3-Joists; 4-Roof; 5-Floor; 6-External walls; 7-Partitions; 8-Ceilings

Advantages

Speed
A prefabricated timber frame is, on average, 30% quicker to construct than block and brick construction. Speed can be of particular importance where you are relying on loans to finance your build. It is worth noting that other forms of timber structure may not benefit from the same construction time saving.

Sustainability
Responsibly sourced timber is incredibly sustainable and is the only mainstream construction material that can claim to be almost infinitely renewable.As well as being renewable, the manufacture of timber materials produces significantly less carbon than other construction materials.

Furthermore, trees absorb and store carbon dioxide, removing it from the atmosphere. Timber products sequester this carbon over the course of their lifetime, meaning some products could even be considered carbon negative.

Aesthetics
Timber homes can be constructed so that they are visually indistinguishable from more typical, masonry houses. However, many find timber aesthetically pleasing and it could be used in a way that brings character to your home.

Wellbeing
Biophilia refers to the innate human instinct to connect with the natural world. Research suggests that biophilic design of the built environment, which incorporates natural materials such as timber, can have measurable beneficial impacts on reducing stress and enhancing creativity.

Some key benefits of using a timber structure

Disadvantages

Cost
The cost of timber systems tends to be higher than other construction methods and this has been exacerbated by recent supply chain issues and material shortages. With prefabricated systems, there can be more cost certainty as costs tend to fluctuate less than on-site builds and the price is fixed once an order is placed.

Maintenance
Timber elements that are not well maintained can become susceptible to rot and beetle infestation. However, in general, if the frame is well protected and the building is properly heated, these conditions will not occur.

Finance
Although people have been building homes using timber frames for centuries, many lenders still consider timber to be “non-standard”construction. This can make obtaining a mortgage difficult, however it is possible. It is essential to establish how your project will be financed early in the design process, as mortgage providers are likely to have specific criteria that must be met.

Final Thoughts

Timber construction methods are long-established and well suited to domestic projects, representing one of the most sustainable construction methods available. However, cost, finance and current supply chain issues all impact the viability of timber frame construction for self-builders. In our view, these factors should not negate the use of timber - provided projects are thoroughly planned and costed. Increasing the use of natural materials in your home could contribute to a multitude of health and well-being benefits as well as minimising your carbon footprint. Great for you and great for the world.