The Pros and Cons of Building with Timber Frame

Not sure if this structural system is right for your home build? Here's the information you need to make the right choice
by Chris Bates
8th April 2018

Offering a quick, cost-effective route to an energy efficient bespoke home, timber frame is rightly popular with self-builders – but it won’t suit everyone. Check out the tips and tricks below to find out whether it’s the best option for your project:

Who can design my timber frame home?

Panelised timber systems are right up there with masonry as a leading structural option. So any architect or house designer worth their salt should be familiar with conventional framing and capable of coming up with a viable scheme that takes advantage of its innate qualities.

That said, your kit supplier will need to translate the approved plans into a buildable reality – and will often take over responsibility for the structural design and engineering. So the process is fairly collaborative. Many framing companies can offer an in-house bespoke design service  for the entire scheme.

What kind of house can I build?

This is a truly flexible building method – allowing you to create a bespoke home in pretty much any style that’s totally tailored to your needs, design tastes, budget and the demands of your plot (or the whims of the planners).

You can even mix the panels with other structural materials, such as steel or glulam (an engineered, laminated timber beam), to deliver features that can’t be cost-effectively achieved with standard framing alone.

How is the frame made?

The overwhelming majority of shells are produced off-site in a factory – although the extent of prefabrication differs according to the complexity of the project and whether you opt for open or closed panel framing. Large parts of the process are computer-controlled, so you can expect accuracy and quality as standard.

The core part of a timber frame is the load-bearing, storey-height walls. These are lightweight engineered panels, each comprising a network of studs encased on either side with a wood-based sheathing, such as oriented strandboard (OSB).

When Elspeth Jones and Fiona Inglis looked at the approved plans for a new home on a stunning plot on the edge of the Lake District, they were delighted at what the saw
Lakeland Timber Frame supplied and erected the open panel frame for the contemporary cantilevered structure. Click the image to read the full story

The gaps between the studs are filled with insulation to create a highly-efficient structural panel – and excellent levels of energy performance can be achieved with relatively slim walls, which can help to optimise internal floorspace.

What will I get in the package?

In addition to the load-bearing wall panels, your frame supplier will manufacture the internal partitions, floor and ceiling joists, roof trusses etc. It will also provide all the components required to erect the shell and make it weathertight (such as breather membranes, sealing tape and – depending on the suite you’ve selected – insulation).

For this reason, many companies in the sector offer their frames as design and build packages – and a large number can even take care of follow-on parts of the project, right up to completion if you desire.

You can expect an eight to 12 week lead-time for your frame to be manufactured. Once ready, it will be delivered to site in lorry loads. Most suppliers offer a design and erect service, so you can use their team to take the shell to weathertight stage (or even through to later phases in the process, right up to completion). Alternatively, you can often select your own general builder to tackle the job.

Find timber frame suppliers and products in the Build It Directory

What isn’t included?

It’s extremely rare for timber frame suppliers – even the turnkey design and build firms – to offer groundworks and foundations as part of their packages. The most they’re likely to do is recommend a partner firm they’ve worked with in your area.

This is important, because it becomes your responsibility to get the foundations and floor slab perfectly square and level within the tolerances your frame manufacturer demands. If you don’t get it right, they won’t put up the shell – and you’ll face delays for remedial works.

Open or closed panel?

In terms of the house you’ll end up with, there’s little difference between these systems. Open panel timber frames are manufactured with the internal side of the walling element unsheathed – so insulation, service runs etc are all taken care of on site. This option should translate into a fairly short lead time for the kit, but it requires more attention to detail and labour on site than its closed panel cousin (which involves a greater degree of prefabrication).

With the latter route the insulation is usually pre-fitted, service channels routed and – in some cases – elements such as windows, doors and plaster are already in place. This has obvious benefits for build speeds, but does mean you need to nail down more of the detail of your design prior to manufacture.

How energy efficient is a timber frame home?

This will of course depend on the specification you opt for, but a standard timber frame built with 140mm-thick wall panels will easily get through the Building Regs.

The prefabrication process means good airtightness is pretty much guaranteed – and if you opt for higher-quality, thicker or additional insulation (such as an internal layer beneath the plasterboard) you can achieve excellent thermal performance that rivals any other system. What’s more, providing it’s responsibly sourced, timber is a carbon-neutral, renewable product – so it’s naturally sustainable.

The only downside of this system in the efficiency stakes is that it’s relatively lightweight; so it doesn’t offer much thermal mass (the ability to absorb heat from the sun’s rays and release it back into the house as internal temperatures drop).

Good thermal mass makes for a predictable heating cycle, which can help to save money on energy bills. You can make up some of the gap versus masonry by opting for features such as concrete ground floors.

What’s it like to live in?

Even in a standard timber frame home, running costs should be affordable – and impressive eco standards such as Passivhaus, which would result in minimal heating requirement, are well within reach. You’ll also enjoy a flexible living space – open plans are easy to achieve, so you can simply partition off rooms with non load-bearing stud walls, which should allow for future alteration.

This passive house scheme features a super-insulated Scotframe Val-U-Therm timber frame superstructure, achieving an ultra-low yearly demand of just 69.40kWh per m2 of floor area
The project combines strong performance with attractive architecture and impressive internal features, such as a double-height, open-plan living room

Soundproofing more than surpasses Building Regulations out of the box, but there’s no doubt that masonry systems have the edge here due to their heavyweight construction. You can upgrade with methods such as using double-skin plasterboard – but this will obviously add to your build budget.

Another consideration is that timber stud walls aren’t solid – so you can only hang heavy items such as kitchen cabinets where there’s a corresponding noggin or stud. It’s important to bear this in mind during the design phases.

How long will it take to erect the frame?

We’ve already mentioned that prefab techniques allow for a quick route to a robust structural shell. This is because – whether you choose open or closed panels – your site team will be erecting vast swathes of walling in one go; as opposed to bedding in individual bricks and blocks.

The labour requirement is also drastically reduced, which means less time and less resource is needed on site. The frame for a typical three-bedroom home can easily be taken to weathertight stage in under a week.

The panels are lightweight and easy to manoeuvre – and some can even be man-handled into position. Large or heavy elements (such as closed panels with windows already inserted) will be craned into place; so bear the plant hire cost in mind.

Your new home’s walls and roof will be left covered in a waterproof membrane, which means work on finishing the shell can proceed both inside and out simultaneously. And because it’s a dry, ultra-fast system, you can work in wet conditions.

Can I change the design on site?

While it is possible to alter your plans as the build progresses, it’s not generally recommended with any construction system. This will inevitably add delay and extra cost to your scheme – especially if your changes require structural calculations.

A far better option is to put as much time and effort into the design stages as possible, right down to choosing the location of switches and sockets.

What will it cost?

Budgets for timber frame construction are comparable to masonry – hence why the two are head and shoulders above the alternatives in terms of popularity. But one advantage for timber is that it provides a greater degree of cost certainty.

This is because you’ll be signing up to a fixed price package for the materials supply and, in many cases, erection of your home’s structural shell. As the frame will be prefabricated to your chosen design, you’ll be expected to pay for it relatively early in the process.

A typical arrangement might be a 25% deposit to enable manufacture, with the rest due in instalments up to delivery – plus installation costs once it’s on site. Lenders specialising in self-build are fully aware of the cashflow needs on this kind of project – but it’s important to make sure your staged mortgage payments reflect the capital outlay.

Top image: Mayfield House by Scandia-Hus is a Tudor-style home that combines traditional looks with modern living. The company designs and builds standard or bespoke properties using closed panel frames complete with windows, doors and internal joinery

There are no comments

You may be interested in

Our sponsors