The popularity of oak framed buildings has seen a steady increase, particularly for self builds, for over two decades. This upswing shows no sign of slowing and oak has shed its traditional image to become a truly modern material of choice. However, many potential users are put off due to lack of knowledge or misconceptions about how easy it is to use. Many are unsure of how long it takes to build a timber frame house or how to go about it. In this blog we will address the need to know basics for oak framed buildings to show how flexible and user friendly oak can be.
Ten points to consider when building with oak
1. Use an experienced designer
While this may sound obvious, many architects and builders are unaware of all the strengths and limitations of oak in building. Designing an oak frame building needs a specialist with experience and understanding of oak frame construction details. Most reputable suppliers of timber will be able to recommend a suitable designer or architect for your project. Many have their own in-house designers to help at this crucial stage to ensure a solid, long lasting build. Why use a premium material and skimp on design?
2. What services does your supplier offer?
Do you know how to build a timber frame house step by step? Can you complete the weatherproof encapsulation without assistance? Many embarking on a self build cannot and may need additional help from their supplier. While experienced builders need no more than the pre–built frames, many suppliers offer further construction services. These can range from simply delivering and erecting the frame to a full ‘turnkey’ service, where the complete build is provided. If your supplier cannot supply a service, they will be able to recommend a professional who can.
3. Offsite construction
Once a design is selected, the components are cut by the supplier and assembled into frames. Construction is carried out by experienced staff, giving a solid, securely jointed structure, ready for assembly. This can then be delivered to the construction site and quickly erected, often in less than a week. The structural element of the frame is then complete. To comply with building regulations, this must then be sealed in an airtight, insulated layer. This is known as encapsulation and is usually done with structural insulated panels (SIPs). These can be cut to size by the supplier at the same time as frame assembly, further simplifying and speeding up construction.
4. Cleaning the structure
Once an oak frame is erected, there may be marks or scuffs from the building process. There may also be water staining, black marks from the tannins in the timber or ‘blueing’ from contact with steel during construction. Cleaning should be carried out as soon as possible after construction, either with oxalic acid or by sandblasting. Sandblasting is a thorough cleaning process but can alter the appearance of the wood and erode detailing on the frame. It also requires professional equipment which can be inconvenient and costly. Oxalic acid is a gentler method, but, despite being derived from the rhubarb plant is toxic and should be handled carefully. Gloves and a breathing mask should be used and manufacturer’s instructions followed closely. This may need more than one application but will bleach stains without affecting the wood finish.
5. It may be cheaper than you think
While oak can be expensive in comparison to other timber, its strength and durability will save on repairs and replacement. Avoiding elaborate features such as complex truss designs will save on the amount of timber used. For rooms where neither the strength or decorative look of oak is a benefit, cheaper materials can be substituted. Even in these cases, decorative oak features can complement the overall look while keeping costs down. Consider using oak for the main frame but substituting other timber for less obvious secondary features. With thought and planning, oak can even suit a modest budget.
6. Consider incorporating steel
A combination of oak and steel is a feature of many contemporary oak framed houses. This can serve a number of aesthetic and structural purposes. Steel bolts can be used to strengthen joints in oak frames while keeping frame design simple without the need for braces. Flitch plates can be used to create especially long, strong beams where oak alone would be impractical. The juxtaposition of industrial and natural components can create an eye-catching design if steel components are left visible. Incorporating steel can allow designs that would be impossible for timber alone and reduce the need for huge, costly beams.
7. Traditional look / Modern solution
Traditionally, an oak frame would be constructed and the gaps between filled with wattle and daub or brick to complete the walls. However, this provided poor insulation and allowed ‘cold bridging’ where heat could leak through. This is why encapsulation is now used, but some homeowners still prefer visible beams on interior and exterior walls. There is a modern solution to this. Instead of encapsulating the whole frame, each section between the beams has a separate insulating panel. Perimeter trims provide a waterproof seal and the outer surface is rendered for a traditional look. This ensures compliance with modern building regulations while retaining the exposed frame.
8. Natural shrinkage
As oak frames for buildings are constructed from green oak that has not been seasoned (dried), they will shrink as they age and dry out. Most of this shrinkage will occur in the first two years after construction. This is a totally natural process and will not affect the integrity of the structure. As the shrinkage occurs across the width of the timber and not along its length, joints will not loosen or weaken. As it dries the timber becomes less flexible and therefore stronger and harder. The cracks and splits which naturally appear during shrinkage are cosmetic and will not weaken the timber. For this reason, green oak should not be used for door or window frames as shrinkage can cause sticking or broken glazing.
9. No need for finishing
As oak ages, its appearance will alter. Sunlight will cause external oak surfaces to silver with time, giving a naturally aged look. Internal oak surfaces will take on a golden hue from oxidation for a warm, homely look. Oak is extraordinarily water and weather resistant so will not need to be treated to resist their effects. It is naturally resistant to fungal and bacterial infection and actively poisonous to many insects. It is possible to use products such as wax oils to prevent the colour change in external oak fittings, but these will need to be reapplied annually. In humid rooms or areas where water may be splashed on oak fittings it may be advisable to oil the timber, but this is not vital. Once in place, oak is one of the lowest maintenance types of timber in existence.
10. Using oak for extensions
Oak extensions are extremely popular. Perhaps you are looking for the complete oak home when extending an existing structure. Alternatively, you could be looking for an eye-catching feature to add value to your home. Oak is the perfect material and suppliers usually have a range of extensions to choose from. An oak extension will require its own foundations, but once these are ready it is quick and easy to erect. It should not be joined directly to an existing structure as the shrinkage could place strain on the join. However, a flexible watertight joint should be incorporated between the two structures. Your timber supplier will be able to suggest the best materials for this.
At Hardwoods Group, we stock a wide range of oak framed building kits and offer a full bespoke oak frame service. Contact us today with any enquiries or to discuss your design. Whether you are planning a new build or the perfect addition to an existing oak home, we can help.