10 Ways to Stay on Budget with a Timber Frame

Want a keen price for the shell of your new home? Tim Doherty looks at how to keep spending under control on a timber project
by Tim Doherty
1st July 2019

Timber framing is a fabulous way to construct a bespoke new house.

It is sympathetic, renewable and beautiful– and will deliver a warm, sustainable and efficient environment. I should know; I used to work in timber frame!

It’s not right for everyone and there are still some prejudices about acoustics and vibration. This being said, timber framing is quick, efficient and a great option for self builders.

Read more: The Pros and Cons of Building with Timber

The market is awash with supplier options, so selecting a firm can be confusing and many of us don’t have the time to deconstruct the process.

However, if you’re keen to save money all the way through your timber build, here are my top tips.

1. Think carefully about design routes

Some timber frame manufacturers offer architectural services, with varying degrees of flexibility.

It can be a tempting option. They’ll know their system inside and out, plus it’s often very well priced. So it will suit those of you who have already decided on a supplier based on their reputation, location etc.

One of the best ways to save could be to engage separate architectural services in design, planning and Building Regulations phases.

Doing things this way will enable you to search the market when you are ready. It also mean you will not be obliged to hire a frame manufacturer because they’ve provided the initial design services.

Copyright usually vests with the designer, so there could be restrictions should want to go elsewhere at a later stage.

2. Show key dimensions on drawings

A common mistake with prefab projects can be a disconnect between the factory-made superstructure and the foundations constructed in-situ.

To avoid communication breakdown, your designer should identify the external wall dimensions on the approved planning drawings (including floor plans and elevations).

This will inform the developed technical drawings. The ground floor plan is key, as this represents the footprint of the house and the setting out positions of the frame, cavity and the external cladding materials.

One thing that commonly causes errors is the use of a brick plinth externally.  This will widen the footprint of the wall and affect where it sits on the foundation. So, keep control and – if you’re using an external designer – supply this information to the timber frame company with good, clear drawings as part of your brief.

3. Get the window & door details right

It’s important that the apertures for all your home’s fenestration are clearly identified on the approved planning drawings. This should include the structural opening size required within the timber frame panels and their specific locations (such as how high they sit above finished floor level and where they are in relation to other internal walls).

This is your opportunity to get the position of the windows and doors exactly as you want in each room. Make sure there’s no ambiguity for the frame manufacturer. The window and door supplier will then size its windows specifically to the structural openings created.

Unless you’re buying the units as part of a package with the house shell, you’ll need to agree fixing, insulation and weathering details within panels and/or cavities with the fenestration supplier. There are no standard details here, so clarity is vital.

4. Work to standard timber sizes

To keep costs competitive, manufacturers will want to use off-the-shelf materials.

Some will stock CLS (Canadian lumber standard) sectional sizes using 38mm x 140mm studs; others will prefer Northern European timber, which is usually graded to a TR26 standard and comes in stud sizes of 46mm x 147mm.

All timber used in panelised frame manufacture is graded to minimum strength standards to qualify. You are probably best leaving the manufacturer to decide which type is most appropriate to deliver your design.

This way they can keep their costs as tight as possible without having to stock something special for you. The best way to achieve this is to ensure your designer regularly works with timber frame systems.

5. Ask for frame-only costs as part of manufacturers’ quotes

Securing a price for the core structural frame can allow you to more easily make comparisons between suppliers.
A frame-only package will typically include:

  •  Sole plates and any holding down strap details.
  • External wall panels for all main above-ground storeys.
  • Internal loadbearing walls (including noggins and braces).
  • All beams (including any steel) for structural openings.
  • Intermediate floor structures, including weatherproof (also known as storm proof) decking.
  •  The roof structure (trusses, rafters, valley boards, braces).
  •  Barge and fascia boards (but not soffits), roofing membrane and enough battens to secure this in position.
  •  Ironmongery (hangers, clips, braces, straps), nails/ screws and fixings for all of the above.

This is your basic, no-frills timber frame, which – when erected – will be structurally sound and weathertight (pending window and door openings being temporarily sheeted). On top of this you might be able to add a variety of services.

These range from insulation (which should be included if you opt for a closed panel frame) through to supply-and-fit (see point seven) and possibly other follow-on options, such as additional joinery (see point nine) or project management deeper into the build.

6. Ensure the manufacturer is responsible for the frame design

As part of the supply quotation, you’ll be expecting your manufacturer to take responsibility for the detailed design of the structural frame.

Yes, you’ve supplied the planning drawings, external dimensions and window and door requirements – but thereafter, the frame provider needs to size the timber components to match your plans. Your manufacturer should therefore have a resident or retained structural engineer who is used to its systems.

As part of this, the engineer will specify details like the type of nails (and their frequency of use), as well as any special connection details required, along with the sectional sizes of all the timber to be used.

At the end of this process they will have produced very clear fabrication instructions, all of which are wrapped up under the umbrella of a design certification.

The only deviation from this might be engineered floor joists and roof trusses, which some firms might then outsource to another specialist. An engineer will complete these elements using a computer model, which churns out the design calculations.

Building control will expect to be provided with the design certificate for your frame and any calculations for the joists and trusses. This should all be included within the overall fee you agree with your frame supplier.

7. Get a price for timber supply and erection

It’s always a good idea to ask for a complete price for the supply and erection of your frame.

Timber panels are large, heavy components – and health and safety requires mechanisation to assist with lifting them into place. Cranes and other temporary plant are expensive, so the process needs to be slick and efficient to minimise the need for this on site.

Fall arrest equipment should also be on site, as well as straps and harnesses for the crew’s individual safety.

Most self builders will go down this shell supply and erection route for their schemes, so that there’s one point of contact for the assembly of all the delivered components.

At the end of the process, the company should leave the site clean and tidy. It is expected that waste should either be collected in one pile or disposed of via skips. This gives you a clean slate for your own trades to crack on with the rest of the project.

8. Insist on a formal handover meeting

You should always have a formal meeting with your structural frame provider at the end of the shell erection process.

The crew undertaking the work might be in-house, but the work is often outsourced. The team will appear, assemble the building and then leave – so you need to be certain they’ve completed 100% of the work.

It’s not unheard of for sub-contractors to do 95% of the work. The sometimes head off on the proviso that someone else will come in to snag the last few items.

To ensure you get the right result, you’ll need someone from the fabrication company to come on site, approve their sub-contractor’s work, identify any snagging items and get these completed forthwith.

9. Ask for separate quotations for ancillary materials

Most timber frame manufacturers will be keen to offer prices for additional materials you may need for your project, which are not included in their standard erection process.

These extras might include non-loadbearing partition walls, plasterboard, insulation and joinery items such as staircases, doors and windows. Many suppliers have great supply chains and will have negotiated powerful discounts, so their offer could be an attractive proposition.

If you’re aiming to keep costs down, the important thing is to ensure that you have clear visibility on the individual prices of these components. Ensure that they’re not all bundled together under one overall fee.

10. Consider alternative framing routes

Standard timber frame is a versatile and cost-effective option in many cases, but it’s not right for every project.

For sites that have very difficult access, for instance, a stick build could be more appropriate.

Here you need two things: first, excellent fabrication drawings showing each timber frame wall broken down into a series of fully-dimensioned panels. This produces a cutting list, so studs and noggins can be pre-sized to make the process quicker.

The second is an excellent carpenter: someone who can read drawings properly; has a logical, practical and efficient approach; and who might relish the challenge of literally fabricating
the house on site. It’s a refined skill and wonderful to see in operation, but it won’t be a quick build.

At the other end of the spectrum, you could look at highly prefabricated options such as systems where the whole external wall (including fenestration, render etc) is factory-made – or even a volumetric (modular) build.

This can be a great choice if you need a super-quick build, perhaps in snowy climates where there are only short windows for construction, or where you’d need to agree road closures near a school.

Although superbly efficient, this option is likely to come at a premium compared to conventional costs for projects without such restrictions.

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