One thing which happens when working this way, is that we’re forced to approach projects differently.
- Transport and store timber in waterproofed flat stacks.. - Engage early with contractors to produce an on-site maintenance plan with special attention to timber elements.. - Enable sufficient drying periods within the project programme.. - Use preservative natural treatments to prevent woodboring and avoid the use of toxic chemicals such as chromium, chlorophenols or arsenic.. - Use preservative natural treatments on all sides to prevent water ingress.Oil based primers penetrate wood better than latex or water-based primers, providing greater resistance and are less likely to be scraped off during construction.. - Consider design details to prevent water ingress during construction and use.. Fire and insurance.
Since the Grenfell tragedy, public policy has shifted towards a zero-combustibility approach in certain higher risk buildings, making the use of engineered timber more complicated.This has increased insurance costs for mass timber construction.It is common practice to solve the problem by enclosing timber for increased fire protection.
Unfortunately, this generates additional carbon emissions and waste.. Another issue with glulam and CLT is the debonding of layers during a fire.The glue can start evaporating at a relatively low temperature causing engineered timber to fall apart even before it burns.
If the timber only chars, it might remain stable but may not be suitable for compartmentation as smoke can break through at joints.. Our response is to:.
- Use engineered timber in lower buildings with a decreased risk of vertical propagation.. - Involve specialist contractors and fire specialists from early stages to ensure the material’s structural integrity in the event of fire and robust co-ordination between disciplines.. - Engage early with statutory bodies, supply chain, and timber contractors.. - Consider the use of sacrificial layers of timber to protect the rest of the structure and potentially result in self extinguishment.. - Use timber fire treatment such as intumescent paint to prevent the spread of fire and reduce the amount of smoke produced, taking account of the impact on recyclability.. - As a last resort, consider full fire bonding if there is a risk of debonding of layers.Design to Value.
approach: considering how the benefits promised by MMC can be maximised to deliver better outcomes for clients, contractors, end users and society as a whole.. To learn more about our Design to Value approach to design and construction, sign up for our monthly newsletter here:.http://bit.ly/BWNewsUpdatesDesign for Manufacture and Assembly (DfMA).
is a whole-project approach, starting with design and working through to assembly.Designing with the detail of assembly in mind, and making sure that M&E engineers work closely with architects and structural engineers, we deliver built assets with performance as part of their DNA.