5 minutes with David Johnson, Managing Director at Off Site Construction Advice Ltd

Mark Goldsmith, our Head of Building Products, has shown more than a passing interest in Offsite throughout his years supporting in the industry, and particularly of late with it being very much back on the government's housing agenda.

During a recent Steel Frame System plant tour, Mark talked to independent offsite consultant David Johnson. David has more than 25 years directing businesses within offsite technologies, including managing Portakabin's subsidiary Yorkon, so Mark was intrigued to understand his views on the industries reluctance to embrace offsite and what needed to be done to educate the sector (something that David now does on a full-time basis as MD of Off-Site Construction Advice Ltd).

Mark: David, you have been involved in offsite technologies for over 25 years. During this time you’ve witnessed peaks and troughs of interest from the industry. Now with Offsite back on the agenda and the press is keen to push the news how do you feel the industry should hold onto this interest, driving developers to construct using these technologies?

David : I believe events are creating an ideal opportunity for the off-site industry; the drive from government to build significantly more homes than we have done for years, the lack of skilled craftsmen, the shortages of traditional materials and the significantly increased cost of both labour and materials, all create the need to find alternative ways of building homes. The good thing is that the alternatives are available – whether that’s modular housing, timber frame housing, SIP panels or traditionally built structures with off-site cladding systems for external cladding and bathroom pods. There are solutions available and the great thing is that it is relatively easy to increase the output because the off-site industry does not need the scarce resources, the skilled tradesmen or the traditional materials like bricks.

Mark: The advantages to using offsite speak volumes but with only 7% of project work completed using offsite technologies, and more worryingly this statistic does not just contribute to the fabric of a building but also includes compartmental pod systems (bathrooms, HVAC housings etc). What in your opinion, is preventing more schemes using these techniques?

David: I believe that one of the main constraints is the lack of understanding of what is possible with off-site construction. Many architects and designers still think that modular equates to “little grey boxes” and that they cannot use their design skills to create the homes that people want to live in or the buildings their clients require, because of the inflexibility of the off-site manufacturing process. While it is necessary to understand the off-site process and its limitations these are significantly fewer than they used to be. If architects and designers want to make use of off-site then they need to engage with the industry and understand what is possible because there is now significantly more flexibility than there was in the past.

There is also a concern among some professionals that if they advise clients to make use of off-site methods they will lose out on fee income. While to some degree this may be true due to most off-site companies have many of the skills in-house, there is still a need for a client to ensure that the initial design meets their needs and the work has to be supervised. Given that, if we use off-site to build housing at two or three times the rate we have been doing in the recent past, there should be plenty of work for everyone.

The final hurdle is cost. The cost is driven by volume so the more buildings that are built off-site the lower the cost will become. The analogy with the car industry is that you only require semi-skilled labour and the more units produced the lower the cost, while factory conditions ensure excellent quality and in construction terms totally eliminate “snagging, delays and cost over-runs”.

Mark: Mortgage lenders have cited a nervousness around the guarantees of quality and longevity of using offsite, quote ‘there is no assurances such buildings will survive 25 years’. What are your views on this and are there any assurances manufacturers can give?

David: The industry has identified this difficulty and Buildoffsite, the industry body which promotes the use of off-site, was instrumental in developing BOPAS (Buildoffsite Property Assurance Scheme), which has been jointly developed by The Royal Institution of Chartered Surveyors (RICS), Lloyd's Register and Building LifePlans Ltd (BLP), in consultation with the Council of Mortgage Lenders (CML) and the Building Societies Association (BSA), to provide assurance to the lending community that off-site constructed properties against which they may be lending, will be sufficiently durable as to be readily saleable for a minimum of 60 years.  The Assurance Scheme comprises:

  • A durability and maintenance assessment.
  • A process accreditation.
  • A web-enabled database comprising details of assessed building methodologies, registered sites and registered/warranted properties.

The object of this is to give everyone involved confidence and security that the properties are as good as, or even better than those built traditionally.

Mark: Much of your work involves advising at the beginning of the construction supply chain; namely developers and architects. What common themes do you come up against when educating such people in your work?

David: I can probably define that up as a lack of belief. It goes back to my earlier remarks about “grey boxes”, many clients and those in the traditional construction industry still do not understand how far the off-site industry has come in recent years; much higher construction standards and greater flexibility. When you look at what off-site construction really is, it can justifiably be described as a steel frame with external cladding and every element used is exactly the same as those used in traditional construction. The only difference is that it is built in a factory and then assembled on site rather than being built on site. 

A comment made by a senior construction director of one of the major national contractors on a Yorkon health project, when returning from a progress meeting with the client, will perhaps sum it up “If I didn’t know that was a modular building, there is no way I could tell.”

Mark: Be it compartmental design or application (commercial, local authority, affordable housing) which area of construction do you see benefiting the most from employing the use of offsite construction in the future?

David: I believe the largest growth in off-site construction will be in housing. That is the sector which has the greatest need and, as described above, the one with the most challenges to rapidly increasing output. The opportunity to make off-site housing an accepted method of construction is here now and what it needs is for clients to seize the opportunity. There are certainly strong moves among some housing associations to do just that and new players such as L&G Homes are entering the market. Once off-site constructed houses start appearing around the country and the general public and the professionals see that they are not World War II prefabs but modern, attractive, well built, superbly thermally efficient homes then the resistance to off-site will disappear and we will enter a new era in construction.  

undefinedDavid Johnson, Managing Director at Off Site Construction Advice Ltd

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