How to Choose Your Timber Frame

Between a quarter and a third of British self-builders choose to construct their homes using prefabricated timber frames, built in factories and delivered to site on the back of a lorry. This is not a new development: since the 1930s, the Ashford based company Colt have been producing timber frame houses for the UK and abroad and there are still many serviceable Colt houses and bungalows around, identifiable by their cedar shingles.

The Scandinavians have also been export­ing their timber houses over here for many years, bringing with them a reputation for being incred­ibly warm and energy efficient — a reputa­tion that has stood timber frame in good stead over the years.

Domestic timber frame businesses started supplying self-builders in the 1970s and, since then, there has been a steady growth in the numbers. There are now around 80 suppliers through­out the UK and Ireland. In Scotland, timber frame has become the predominant method of housebuilding and recently timber frame has been seeing rapid growth through­out the rest of the UK and Ireland.

Self-builders like timber frame because it takes away many of the headaches involved in building a house. Rather than spending months dealing with brickies, carpenters and roofers, they are able to pre-order the super­structure and see it arrive and get erect­ed on site in days. The whole process tends to get handled by one company who, more often as not, sort out the planning permission and building regulations as well. Generally, timber frame simplifies the process of homebuilding and yet still enables self-builders to make savings by organising the finishes themselves.

There are other perceived advantages in using timber frame, appreciated by all build­ers. Timber frame is an engineered prod­uct that forms a structure that is dimensionally accur­ate. Walls are straight and rooms are square. Kitchen units fit perfectly; skirtings and covings don’t need to be pushed into awkward shapes. It’s also a dry process: that means that the problems with cracking and shrinkage, which bedevil masonry homes generally, rarely happen in new timber frame constructions.

Explore Your Design Options

Many people don’t realise just how flexible the design service offered by timber frame com­pa­nies is and think that they will have to build one of the standard house types shown in the brochure. However, the brochures tend to be there principally as sales aids — and it is in fact quite rare for a timber frame company to build a house ‘straight out of the book.’ Almost every customer wants his or her own ideas incorporated into the design. Some­times this will be done by adapting an existing house type and at other times it will mean starting from scratch.

Whether you go directly to a timber frame company for a design or start with an architect makes little difference to the timber frame companies — though many would argue that their own in-house design teams are more than capable of drawing up anything you might want to build.

One of the reasons that self-builders don’t choose timber frame more often than they do is that their chosen architects don’t draw timber frame houses. It’s much easier and less technically demanding to draw up a masonry house: a block or brick wall is just two parallel lines on a sheet of paper whereas a timber frame wall has to have some thought given to it to decide where the vertical studs should be placed, bearing in mind spacings for the lining boards and loadings for the floors and roof above. Aware of this problem, timber frame companies invariably have technical designers working with them who are able to undertake conversions of masonry designs. It tends to be the province of the technician and the CAD package rather than the designer and it’s usually a service timber frame house suppliers are happy to carry out as part of their package, along with the work required for a building regulations application.

If you have house plans drawn up with masonry walls, ask the timber frame com­panies if they can undertake a design conver­sion as part of their package — you’ll find most more than happy to do so.

Beware floor measurements

There is, unfortunately, no standard method used to measure floor areas in houses. Areas taken up by the external walls, garages and under eaves cupboards are usually excluded from floor area calculations (known as ‘net’) but are from time to time included (known as ‘gross’). Consequently, a house with an attach­ed garage could have a floor area as little as 120m2 or as much as 160m2, depending on what is included in the defini­tion of floor areas.

Check the small print in the brochure to see if the house types are measured ‘net’ or ‘gross.’ Failing that, you should check one or two floor plans with a ruler to see how the floor areas have been calculated.

Find out a company’s lead-in time

One of the major selling points of timber frame is that it’s a quicker way to build. When you see the superstructure going up in a week, it’s easy to understand just why. Having a watertight shell erected so quickly enables you to get on with both internal and external finishes simultaneously which further increases the time advantages of timber frame.

There is, however, an enormous amount of planning and constructing going on before the house ever gets to site and it can take many weeks or even months before the kit is ready to deliver. With demand for timber fram­ed houses steadily increasing, many timber frame companies are warning cus­tomers that they may face a lengthy wait before their house kit can be delivered. Lead-in times vary from company to company and from season to season – things tend to be quieter in the winter months – but at busy times you can sometimes be asked to wait up to 16 weeks, though 4 to 8 weeks is probably a more normal time frame. Whilst timber frame houses invariably go up very quickly, this advan­tage can be squandered by lengthy lead times.

Ask at the outset what the likely lead times are with each supplier you interview. Realistically, four weeks is as short a time delay as you would expect or even want — it can take this long to carry out the foundation works.

Get the foundations sorted early

Unless the timber frame company is contract­ed to undertake a full build or turnkey service, the self-builder is expected to arrange for the foundations to be completed by the time the timber frame kit is ready. This can present problems because foundation works do not always proceed in a straightforward manner.

It’s best to check out the ground conditions as much as possible before you start work. An informal chat with the local building inspector or a friendly local builder usually pays dividends. If in doubt, get a structural engineer to carry out a soil survey. If problems are encountered, the engineer will design a solution before work commences.

There is, however, something else to watch out for when building in timber frame. Timber framers like to work off a flat surface — and one with square corners. A timber framed house should, therefore, be built off accurate foundations. If you are building with masonry materials, the precision of the foundations is of less importance. Bricklayers are adept at adjusting the heights to which they are building and squareness is sometimes just neglected. Colin Taylor of Taylor Lane comments that badly built foundations remain a problem for all timber frame housebuilders. “We find that groundworkers tend to either get them right every time or never get anywhere near.” It therefore pays to use good groundworkers: your timber frame supplier will be only too pleased to point you in the right direction.

Building good, accurate foundations is not difficult, provided your groundworkers know what they are doing. You should specify that you want the floor slab to be level overall to within plus or minus 10mm and that the dimensions of the slab should be similarly accurate. The height can realistically only be checked with a professional level but the squareness of the foundations can be check­ed using a surveyor’s tape measure.

Establish a payment system

A timber frame house kit is worth a consid­erable sum of money — rarely less than £15,000 and, in many cases, as much as £50,000. It is built in advance in a factory or workshop and virtually every kit is a one-off. Given the sums involved it is understandable that the majority of timber frame companies require some sort of deposit from their customers and many require payment upfront before they begin. This presents two problems to self-builders: secu­rity and cashflow.

It’s rarely a good idea to pay for anything upfront and the more expensive the item, the greater the risk. Timber frame companies are generally very reputable and, in the past few years, they have enjoyed good trading conditions — but that is no guarantee that they will continue to prosper indefinitely. It is therefore vital that you should be aware of the payment terms and conditions required. They vary a great deal.

Some, such as Taylor Lane, one of the top ten producers in the UK, generally require just a 10% deposit with order and then the balance to be paid after delivery and erection. However, many others require the bulk of the payment to be made when you place the order, which could be several weeks before the kit arrives on site. Generally, there is no problem with this arrangement provided the payment is held in a third party account which protects you in event of the company ceasing to trade during this period.

A spokesman for the UK Timber Frame Association (UKTFA) says: “It is our contention that by employing this upfront payment method we offer clients the lowest cost method of securing their homes. While some companies do operate a ‘third party’ account system, this adds to administration and servicing costs, which must ultimately be carried, at least in part, by the client.”

The Swedish House Company operates such a system. All their houses are made in Sweden and shipped over to the UK: in addition to a deposit of 5% when the order is placed, they also also require the balance (i.e. the other 95%) to be lodged in a solicitor’s stakeholder account until the house is delivered.

If you are asked to pay a substantial amount of money directly to a manufacturer before delivery then you should, at the very least, check out the financial standing of the company. The best option is to look very carefully at the payment terms demanded. If you feel uncomfortable about paying upfront, then raise it with the company and put the onus very firmly on them to allay your concerns.

Further Reading:

• A Guide to Timber Frame
• Off-site Kit Houses: A Greener Build?
• Building with Timber Frame