James Mead, Projects Director at Saint-Gobain Weber, and Mike Doolan, Sales and Partnerships Manager at LoCal Homes, share their experience of combining traditional building products with offsite manufacturing.
In 2019, the government set a target of 300,000 new homes a year by the mid-2020s. This figure was originally unveiled in 2017 by then Chancellor Philip Hammond as the number of new homes needed to make "inroads on the affordability of housing."
The closest we have been to achieving this target was in 2019-20 with 243,770 net additional dwellings. With housing output continuing to fall short, it has been debated over recent years whether increasing the use of modern methods of construction (MMC) is the quickest way to reduce the deficit. The government seems to be supportive of this approach and is encouraging the use of MMC via initiatives like the Affordable Homes Programme (AHP) from Homes England which requires strategic partners to deliver 25% of homes using MMC if they'd like to access funding. Under the AHP, homes will only be considered as "being delivered using MMC" if they have a pre-manufactured value (PMV) score of 55% or more.
In 2020, real estate advisor Savills predicted that the proportion of homes built using MMC over the next 10 years would rise from around 8% to closer to 20%. "Awareness of the possibilities that offsite construction offers is definitely increasing," says Mike. "The drive from government, as well as the need for housing associations to deliver new homes that meet the new Part L (conservation of fuel and power) Part F (ventilation) and Part O (overheating) requirements of the Building Regulations in England, are providing a good platform to showcase the benefits of using MMC. We've also found that there is a growing appetite for offsite timber frame with factory pre-fitted external finishes. An offsite panelised timber frame is a viable alternative to full modular or volumetric systems due to its lean and flexible production processes."
Traditional facades, modern construction
Although clients are more open to building this way, many still want newbuild homes to have a traditional appearance. Around 70% of the UK's new homes are built with a brick façade, and therefore, James argues, more traditional products still have a large role to play. "Category 6 of the MMC definition framework includes traditional single building products, that are manufactured in large format, pre-cut configurations or with easy jointing features to reduce extent of site labour required to install," explains James.
"As we transition from traditional building methods to offsite manufacturing, products within this category are set to play a huge part in bridging the gap. Builds will become quicker thanks to the ease and speed of installation, and there will be, on the whole, no requirement to retrain, as existing labour is sufficient – it simply needs redeploying." Weber developed its weberwall brick – a fast-fix, lightweight brick system – as a solution for offsite manufacturers who wanted to give their homes a brick finish without having to manually apply brick slips.
"When we were looking for a brick slip system to use on our closed panel timber frame system, we found lots of them required additional labour and works on-site to achieve a similar appearance," says Mike. "This impacts both the assured quality of the build and speed of programme. Introducing site application also reduces your build's percentage of PMV which goes against the whole principle of offsite construction. We also needed something that wouldn't add lots of additional weight to the panels. Using a brick effect finish like this can also help us meet the requirements for colour and brick texture as required by planners."
"The weberwall brick suited LoCal Homes' system because it can be fixed more than three-times faster than traditional brick slips and one sheet, which contains 20 bricks, weighs the same as one brick so only adds 13kg per metre squared to the timber frame panel," adds James. A lighter overall wall structure means that the build can become more efficient in other ways such as foundation design. Smaller foundations means that less concrete is required.
Benefits of factory application of final facades
Weber worked with LoCal Homes to develop an efficient application process with minimal waste. "We've designed a precise setting out method which enables projects to be priced accurately with very little wastage," says James. "Lasers are used in LoCal Home's factory to ensure accuracy when making any cuts and we've also optimised the adhesive application to make it even faster.
For LoCal Homes, another benefit of keeping all elements of the build within the factory includes being able to buy products in bulk and store them in secure, weathertight facilities which helps to maintain a steady flow of products. "There are two huge benefits of working this way – noticeable time improvements on project delivery and the ability to design and build more sustainable homes in line with the latest standards," says Mike. "There is no 'down time' as the works aren't weather dependent. And that's not just bad weather - during this summer's heatwave lots of building sites had to pause works further highlighting the advantages of manufacturing offsite.
"We are currently producing around 1,000 units a year and are expecting an increase in social housing orders because closed panel timber building is extremely efficient, helping all stakeholders towards net zero targets and will also help to ensure adherence to the uplift in Part L that came into place on 15 June, as they can be constructed with this in mind." LoCal Homes is currently using weberwall brick at a development in Daventry where it is building two three-storey blocks to create 22 apartments, and in Kirton, Lincolnshire, where it has been used on two bungalows and four houses.
For more information visit: www.uk.weber www.localhomes.co.uk
Source: Offsite Magazine
