Timber Frame Construction
What is
Timber Frame Construction
Timber frame construction has been around since Neolithic times, but still remains a major mainstream construction method in the UK. The cost, flexibility and time saving of timber frame have maintained its position for largescale new build developments as well as for the self-build industry.
Timber frame utilises timber studs and rails in addition to a structural sheathing board, such as OSB or plywood, to form the frame which transmits all the vertical and horizontal loads into the foundations.
The resurgence of timber frame construction since the slump of the mid 80’s is based upon many things, such as speed of construction and flexible specification, but in an era where sustainability has become a keyword in building, timber frame can tick many boxes.
Timber Frame Diagram
What types of sheathing boards are acceptable for timber frame construction?
According to the NHBC Standards (January 2021), sheathing boards should be durable and capable of providing structural resistance to cracking.
The following material are acceptable in the standard – Plywood – Oriented strand board – Moisture-resistant chipboard – Medium board – Impregnated soft board – Proprietary sheathing materials.
Please see section 6.2.7 of the NHBC Standards.
Does timber frame suffer from differential movement?
Why do you need a drained cavity system for residential new build?
New build warranty companies require a drained cavity whenever a timber or steel frame construction is used for residential purposes.
According to the NHBC Chapter 6.2.10, (External timber framed walls) the cavity requirements for masonry is 50mm, for render onto a board background this is 25mm and for other types of cladding a 15mm cavity is required.
How should you insulate within a timber frame?
Insulation should be breathable, such as rock or glass wool or assessed in accordance with Technical Requirement R3 for use in timber frame wall panels.
Does timber frame require a vapour control layer?
Generally vapour control layers should be 500-gauge (120 micron) polyethylene sheet, vapour control plasterboard or a product assessed in accordance with the relevant Technical Requirements
And should be adequately fixed to the warm side of the insulation and frame.
What is the environmental impact of using timber?
If sustainably sourced then timber frame construction has a very low CO2 impact compared to other types of construction methods.
Timber harvesting allow for the use of the mature trees and these are replaced with younger ones.
In the UK we have two main certification schemes, Forest Stewardship Council (FSC) and Programme for the Endorsement of Forest Certification (PEFC), which assures that all wood and wood-based products originate from sustainable sources.
How high can you build with timber frame in the UK?
The current regulations will allow for approximately 6 storeys; however, the government are reviewing reducing the height at which you can use combustible materials down from 18 metres to 11 metres.
If this is implemented then this would reduce the maximum amount of storeys down to 3 or 4.
What external finishes can be used with timber frame construction?
Can you insulate an existing timber frame property?
Depending upon the property then yes you can add extra insulation; however, you will be changing the composition of the wall and specialist advice and condensation analysis should be sought.
If the property has historic importance then the possibility of thermally upgrading will be dramatically reduced.
Old properties which cannot be insulated can benefit from draughtproofing measures as potentially there are cracks at joints which allow for the heat to escape.