In recent weeks, Kirkwood Timber Frame’s sales team has been speaking with English customers, to try and understand the concerns that may exist towards timber frame south of the border.
We hoped to uncover some of the beliefs held by decision makers, when comparing timber frame to traditional building methods. Here, Kirkwood Timber Frame’s Managing Director, Malcolm Thomson, explores these in more detail.
Malcolm says: “The construction industry has evolved - and the timber frame sector has adapted with it. Much of the feedback we received during our discussions focused on challenges people faced decades ago, rather than those people face now.
At a time when net zero targets play a significant part of the planning process - and when the consensus is that we need to deliver homes sustainably and quickly - timber is now the natural (no pun intended!) choice for housebuilders.
In addition, with pre-manufactured Values (PMV) needing to be of a certain level to access Homes England funding for affordable housing projects, adopting a precision engineered, sustainable product that can be assembled quickly and efficiently will play a huge part in unlocking more development sites.”
Cost prohibitive?
“The first point that was raised by our clients as to why they felt other developers in England were unsure about timber frame, was cost. Timber has long been viewed as more expensive. However, most people who say this may not fully understand its additional benefits. These include: Reduced foundation costs, faster construction times, improved thermal performance, reductions in the number of trades required and the amount of labour needed and lower prelim costs - as just a few examples.
Equally, independent cost analysis studies have shown there to be little difference in outlay so when the added benefits are factored in, timber frame often works out much more cost effective than a traditional build. With the homes delivered more quickly, a faster return on investment can also be achieved.”
Shrinkage?
“Another concern mentioned was around potential shrinkage but with more highly engineered products on the market in recent years, timber frame performs much better that masonry in this area too. Precise products and the use of less wet trades means less cracking and shrinkage and fewer snagging defects and maintenance costs - again representing a further saving to the developer.
The STA’s Assure accreditation programme - of which we hold gold accreditation – sets out rigorous quality standards which members need to comply with in regard to manufacturing and training. This includes the frame installers who should also be STA members. Understanding of the building tolerances for timber frame is also important and therefore adherence to the details provided is crucial.”
Not suitable for larger structures (buildings over two storeys)?
“It was mentioned that some believe timber frame to be far more costly for delivering buildings of over two storeys. This is not the case. For apartments up to five / six storeys, timber frame is in its element due to how it deals with the disproportionate collapse engineering with which all buildings of height must comply. This actually makes it less expensive.
Our specialist consulting engineer commented: ‘Although timber frame projects are ideally suited to repetitive cellular or box-like floor layouts - such as flatted housing developments, student accommodation and hotels - timber frame construction has also been successfully used in a wide range of multi-storey projects. This includes those where repetitive floor layouts were not always possible.
"Engaging with your specialist consulting timber frame engineer early in the project will help ensure the most cost-effective solutions are proposed. Even minor architectural changes - such as ensuring the direct alignment of partitions on different floor plates or increasing a wall from 89mm to 140mm for example - can lead to significant cost savings.”
Combined with benefits already outlined – and in addition to savings within the superstructure - another advantage of timber frame construction over alternative
methods, is the reduced self-weight of construction materials. This results in lighter loads acting on the foundations and / or transfer slabs, which is especially critical in areas with poor ground conditions. Lighter superstructure loads can often eliminate the need for ground improvement measures.
Another concern we heard raised about timber frame not being suitable for sloping sites can also be countered by the reduced weight this method of construction delivers.”
Issues with NHBC Warranty and fire safety concerns?
“We were told of other misconceptions, during the construction phase, about the ability to secure NHBC Warranty on timber frame developments and around fire safety performance. On the former, the NHBC will warrant a timber frame site in the same way as they would a brick/block site. Indeed, the NHBC will warranty timber frame homes up to 7 storeys in height. The NHBC Standards website, which includes a section specific to timber frame walls, can be found here.
On fire safety, and separately, the timber frame sector has done more work on this than any other form of construction in recent years, through the STA’s Site Safe programme and its 16 Steps to Fire Safety Guide. All members need to comply with this. The process has been written with the support of the HSE and is endorsed by both the HSE and the Construction Insurance Risk Engineers Group.
On endorsing the guide in 2017, Peter Baker, Director of HSE Construction Division, said: 'Fire is a hazard during most construction processes and it is important that precautions are in place to both prevent fires and ensure that people can escape to safety if fire does occur... proportionate steps are [should be] taken to manage the risk from fire and these are [should be] planned during the design and pre-construction phase, and then implemented fully during the construction process.
'This guidance is helpfully set out for Construction (Design and Management) Regulations 2015 duty-holders such that designers and contractors can follow the specific aspects of the 16 steps process that apply to them. HSE will continue to work with STA on this issue but in the meantime endorses this guidance, as it follows a sensible and proportionate approach to managing health and safety.'
Ade Adeyemo, Chairman of The Construction Insurance Risk Engineers Group, added: 'We are pleased to endorse the 16 Steps to Fire Safety -Version 4, produced by the Structural Timber Association (STA), as Best Practice for managing fire risk during construction.'
At Kirkwood Timber Frame, quality assurance is one of our top priorities
That's why our precision-engineered FastBuild® Closed Panel timber frame system has secured Premier Guarantee and LABC warranty certification as well as STA Assured Gold, CATG Frame Mark and ISO9001:2015.
For more details on our innovative FastBuild® methodology, click here.
