MMC – The Impact on Skill Requirments

If the ambition of 300,000 homes was met by home building using current construction methods, it would require an additional 195,000 workers by 2025.

Read the CITB (Construction Industry Training Board) report summary.

This research was carried out to consider the effect that increased uptake of Modern Methods of Construction (MMC) in home building could have on the workforce requirements for delivering new homes in England as the Government looks to deliver on its Housing Ambition.

The analysis shows that increased uptake of MMC can influence future workforce requirements and help to mitigate some of the occupational demand pressure.

The impact of modern methods of construction on the skills requirements for housing

This research was carried out to consider the effect that increased uptake of Modern Methods of Construction (MMC) in home building could have on the workforce requirements for delivering new homes in England as the Government looks to deliver on its Housing Ambition.

The analysis shows that increased uptake of MMC can influence future workforce requirements and help to mitigate some of the occupational demand pressure.

If the ambition of 300,000 homes was met by home building using current construction methods, it would require an additional 195,000 workers by 2025.

However, increased use of MMC could reduce this to around 158,000 additional workers.

The report also highlights that the home building sector looks set to face a series of challenges:

  • In the short term it will need to grow and develop workers to support homes built using the current construction methods.
  • While in the medium to longer term it will be necessary to maintain the onsite workers at the same time as developing the offsite workforce to deliver MMC builds.
  • There is also the need to upskill existing workers to cover the site management, integration, onsite placement and assembly that will be increasingly required for MMC.

You can read the full report here.

 

SOURCE: Construction Industry Training Board

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Offsite: a healthier way of delivering homes

England is short of four million homes. There are at least 320,000 homeless people throughout Britain and over a million on housing waiting lists. Needless to say, the housebuilding industry needs to change. The only way this can happen is if we look in on ourselves and our own behaviour and acknowledge our shortcomings; something that is hard to do. MMC Editor Joe Bradbury investigates.

The bad news is that the UK construction industry is currently responsible for 45% of total UK carbon emissions, 32% of all landfill waste and is responsible for more water pollution incidents than any other industry. The good news is that we have the knowledge, skills and technology to facilitate real change in the world, when we put our minds to it. Implementing offsite construction into the housebuilding sector could be the catalyst.

Waste not, want not

One of the key factors that will either seal our reputation as innovators or sully it indefinitely is the materials we use and how we choose to use them. With an unprecedented shortage of housing in this country, it is clear to see that despite what construction industry doomsayers print, the UK has a voracious appetite for housing that isn’t going away any time soon.

The construction industry is the largest consumer of natural resources in the UK today; a stark point that highlights just how high up on the agenda reconsideration of our building practices should be. The impact of our materials usage on the environment in of itself is staggering; a recent report by Willmott Dixon Group suggested that the construction industry alone is accountable for around 45-50% of global energy usage, nearly 50% of worldwide water usage, and around 60% of the total usage of raw materials.

The benefits of adopting more considerate ways to use materials are far-reaching. Take FSC-approved timber as just one of many examples; manufacturers who use forest products that are FSC approved can do so with confidence, safe in the knowledge that they are helping to ensure our forests are alive and well for generations to come. But the benefits are also far more immediate and closer to home than that; wood is a natural, renewable material, used often in modular building. It offsets our carbon footprint and offers significant thermal efficiency, keeping energy bills low. For the four million people in Britain living in fuel poverty today, building more energy efficient homes using modern methods of construction is urgent. Interestingly, if housing targets were met through timber-frame construction alone, new build homes in the UK would serve as carbon ‘banks’, capturing and storing nearly 4 million tonnes of CO2 every year.

Better for the environment

According to ‘The Waste and Resources Action Programme’, offsite construction can generate up to 90% less waste than traditional onsite building methods. This is largely because a factory is a much more controlled environment than a traditional building site – with far fewer variables

Modular construction offers a greater degree of reusability; buildings can often be disassembled and moved to another site entirely if necessary. They can be shifted and repurposed when required. However, should a modular building find itself no longer fit for requirement as it stands, many of its components can be salvaged and re-used in another project, reducing the need for fresh new materials in each new build. This reduction in materials usage protects depleting stock of resources whilst simultaneously lowering waste.

Offsite construction is far less energy intensive than traditional housebuilding methods. The carbon footprint left by the many construction vehicles and machinery on the site of a traditional construction project alone is considerably larger than that of modular construction. Put simply, fewer vehicles involved and less time spent on site results in less greenhouse gases being released into our environment.

And due to being built away from the construction site, modern methods of construction such as offsite and modular are a great way to reduce and control noise levels, causing less disruption to the environment and the people around it.

To summarise

The positive effects of modular construction on the housebuilding industry cannot be overstated, and with the UK Environment Agency and other government bodies putting increasing pressure on construction companies to reduce pollution and conform to environmental regulations, it is clear to see that change is imminent – embrace the future, build homes offsite.

 

 

 

 

 

 

 

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James Jones partners with Ockwells

James Jones Timber Systems Division forms partnership with Ockwells to offer stairwell protection systems to UK housebuilders.

James Jones & Sons’ Timber Systems Division, the maker of the UK’s market-leading I-Joist system, JJI-Joists, has entered into a partnership with specialist building and protection materials manufacturer Ockwells, which will see it recommending Ockwells’ Stairwell Hatch System to all JJI-Joist customers in the future.

After months of research in to available stairwell protection systems, James Jones’ Timber Systems Division has opted to recommend the Ockwells temporary site protection system because of its superior build quality, flexibility in applications of use and the simplicity of installing the system to house building and construction sites without adaptation to existing build practices.

Independently tested and verified, the Ockwells Stairwell Hatch System is designed to provide full cover platforms over the stairwell openings in various combinations to suit all build sites and conditions. Once installed, the system prevents falls through large stairwell opening whilst giving access for operatives and materials.

The system is designed to be lightweight for handling and ease of use on site and it allows safe and fixed access to a ladder prior to a staircase being fitted. The system comprises three parts – hinged and framed glass reinforced plastic (GRP), a steel ladder plate for securing a ladder and a steel box sections adjustable telescopic joist, which allows openings next to party walls to be accommodated by the system.

Speaking of the joint venture Mark Tilston, Systems Development Manager for James Jones’ Timber Systems Division, said: “Stairwell protection systems is something that our business has been investigating and researching for a while now and we are delighted to have found in Ockwells a partner that provides a robust and safe solution for all JJI-Joist distributors and end users.

“The Stairwell Hatch System is well designed, solidly manufactured and above all, it works. They have also produced a simple step by step installation guide which gives you clear advice on many applications. The system allows you to continue using crash deck systems and bird cage platforms which is unique. Their product has been independently tested to give you confidence.”

John Gray, Sales Director at Ockwells, said: “Ockwells are delighted to be partnering with James Jones’ in this new and exciting development. Having spent a great deal of time developing the Stairwell Hatch System it’s great to see that our customers are seeing the benefits from our safety system.

“As well as providing a safe working platform over stairwell openings, the Stairwell Hatch System is also very cost-effective, being reusable means that the initial investment is quickly recouped when compared to the cost of using sacrificial joists, which can run into hundreds of pounds per plot. We believe that the combined expertise of James Jones’ and Ockwells will result in significant health and safety, and cost benefits to James Jones’ customers.”

www.jamesjones.co.uk

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The Active – Office of the future

The UK’s first energy positive office, the Active Office, was opened in June last year at Swansea University. Designed by SPECIFIC Innovation and Knowledge Centre to be powered entirely by solar energy, the Active Office aims to generate more energy than it consumes over the course of a year.

The Active Office isn’t just meant to be a high performance building for its own sake, but also to demonstrate how well buildings can perform with technology available today. The building is packed full of cutting edge, commercially available technology to help generate, store and manage energy for the building.

One piece of technology provides both electricity and heat to the building; the photovoltaic thermal (PV-T) system by Naked Energy. Made up of a number of photovoltaic panels contained in vacuum sealed tubes, the system has been mounted onto the front elevation of the building and could potentially provide heat energy for the entire building through spring, summer and autumn.

More solar energy is collected through the roof which is covered in, or more accurately made up of, solar cells. The PV cells are bonded directly onto pre-painted steel to create a roofing system that can be installed using conventional methods. The Active Office features the first commercial installation of BIPVco’s technology on a curved profile, which aside from adding architectural flair, will also generate power throughout the year even in low light conditions.

The various systems are monitored by extensive metering installed throughout the building, enabling SPECIFIC to determine where energy is being generated and consumed. This is reflected in a real time display in the entrance foyer, allowing occupants and visitors to find out how the building is performing.

However, the building can’t reach its energy positive target if all the energy it generates is wasted. “We took a fabric-first approach to reducing energy consumption,” commented Joanna Clark, Building Integration Manager with SPECIFIC and Architect for the Active Office. 

The Active Office was designed and conceived by SPECIFIC Innovation and Knowledge Centre and funded by Innovate UK with support from Swansea University and the European Regional Development Fund through the Welsh Government.

It was manufactured offsite by Wernick Buildings, in their factory in nearby Port Talbot. SPECIFIC knew that modular construction could deliver the levels of performance they needed against a challenging programme and budget.

Months later, the choice of modular is being borne out by data. On current performance, SPECIFIC predict an annual consumption of approximately 20MWh versus an annual generation of 24MWh.

The future looks bright for this new type of solar-powered building design. In September, the Chancellor of the Exchequer Philip Hammond announced funding for the Active Building Centre through the Industrial Strategy Challenge Fund and UKRI. The new independent national centre will seek to remove barriers and accelerate market adoption of new Active Buildings. 

It seems likely that modular construction will play an important part in progress towards a low carbon future. 

For more information:

www.wernick.co.uk | www.specific.eu.com

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CROSS LAMINATED TIMBER (CLT) AND ITS USE IN STRUCTURES

Premier Guarantee Technical Standards Manager, John Gilbert, provides technical guidance on the treatment of Cross Laminated Timber. The recent interest in ‘modular buildings’ as a solution to the housing crisis and current skills shortage, has brought forward the potential use of ‘CLT’ (Cross Laminated Timber) as a structural panel to produce wall panels or indeed modular pods.

A number of CLT products have third party product approval for the use as a structural plank for construction uses. However, it is also important that manufacturers have a quality management process to ensure consistent quality. Usually these approvals and manufacturing processes are for the solid plank and therefore full designs of the construction including its external cladding. are required on a site by site basis. CLT as a structural timber product isn’t preservative treated. It is also difficult to ‘post treat’ the panels due to the compact layers of softwood timber making penetration of the preservative across the full cross section difficult to achieve. So, it is important that the design keeps the CLT panel completely dry, particularly at ground level and around critical junctions.

Where structural timber, such as these wall panels are to be used in an external wall construction consideration should be given whether timber treatment is necessary if the species of the timber isn’t sufficiently naturally durable.

The vulnerability of timber in external walls is particularly critical where the timber is positioned in certain areas including at the horizontal damp proof course without the inclusion of a treated sole plate. Whilst the use of CLT panels in external walls is a relatively new occurrence in the UK, wall panels incorporating CLT have been successfully used in Europe.

Premier Guarantee are actively involved with the Structural Timber Association and have recently supported and endorsed technical guidance produced by the STA. The recently reviewed CLT guidance is available via:

STRUCTURAL TIMBER ASSOCIATION: www.structuraltimber.co.uk

BM TRADA: www.bmtrada.co.uk

FOR OUR WARRANTY PURPOSES:

Where projects are proposed that incorporate CLT wall panels; they must not be used with a render or other cladding system that is directly bonded to the wall panel. A drained and vented cavity must be provided.

The CLT panel must be suitably protected as follows:

At DPC level:

The CLT wall panels can be positioned directly onto the horizontal dpc (over the substructure

walls) without a treated timber sole plate providing that:

• The DPC extends at least 50mm past the face of the CLT and in the case of on the cavity wall side- extends down 50mm below the horizontal DPC without bridging the cavity.

• The lowest level of the CLT panel where it sits onto the horizontal dpc must be not less than 150mm above the finished ground level. The residual cavity must extend 225mm below the lowest horizontal DPC level.

• Open brick perpends / Weeps should be sited under the external horizontal DPC in the cladding at 1200mm centres.

• Measures to prevent cold bridging at the substructure wall / ground floor / CLT wall panel junctions must be in place.

• Ground levels immediately in front of the external wall should slope away from the building cladding.

• CLT panels must not be constructed into ‘troughs or pockets’ e.g. for an internal wall panel on a structural slab. The risk of hidden damage from accidental water leaks could lead to moisture collecting around the panel.

Above horizontal DPC level:

• All exposed end grain to the wall panel must be suitably treated (e.g. end grain edges of the panel or where holes are cut through the panel to form openings – windows, doors, flues etc.) The end grain sealant should extend 50mm onto the panel sides.

• There must be a drained and vented cavity with a minimum 50mm residual cavity retained.

• The external wall insulation must be a ‘breathable’ type insulation and directly fixed to the CLT wall panel.

• An approved breathable membrane must be installed to protect the insulation on the cavity side.

• Suitable approved wall ties must be used which are secured to the CLT panel.

• The CLT panels should be protected on the ‘Warm side’ by a suitable vapour control layer

(vcl) unless interstitial condensation risk analysis calculations prove that the risk of interstitial condensation will not occur within the construction.

• The structural engineer must provide details of suitable mechanical fixings to secure the CLT panels to the substructure.

Generally:

• The project using CLT panels must be supported by full structural design specifications.

• General construction should follow the guidance contained within Timber frame section of the Technical Manual.

• Detailing for Gas membranes must be considered on a project by project basis and you should consult with our Warranty Surveyor for further advice.

 

www.premierguarantee.com

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The Flint Walls of Dover

Milbank Concrete Products recently worked alongside RG Group on the design, manufacture and installation of over 90 specialist precast concrete flint embossed retaining walls at the St James Retail Leisure Park development in Dover, with an estimated contract sum of circa £24m. 

The St James development has transformed the retail and leisure offer in the heart of Dover and south Kent and is located on the A20, the main road leading to the Port of Dover, making it highly visible and accessible to visitors, tourists and those travelling to and from the port.

The development comprises a range of outlets including an M&S store, a six-screen multiplex Cineworld cinema, a 108-bed Travelodge hotel and five national chain restaurants, along with a further 12 retail units ranging in size from 2730 to 16,000ft2 (254 to 1486m2). With over 450 car parking spaces and 156,915ft2 (14,578m2) of new retail and leisure space in total, the development is well equipped to cater for a large number of visitors on a daily basis.

 

Design and construction

Milbank produced 97 precast concrete walls in total, ranging from 6 to 11 tonnes, using four separate timber moulds. The complex moulds were handcrafted by skilled, in-house carpenters and specific requirements were agreed with regard to the flint layout by Dover District Council, Dover Planning Departments and the site contractors in co-ordination with Historic England, using examples of local existing flint walls. 

The flexibility of having four individual moulds allowed the production team to hand-lay the flint into two moulds, while the remaining two moulds were poured. The panels were cast over a ten-week period at Milbank’s precast concrete factory in Earls Colne. During the casting process, sand was used as a bed within the timber moulds to assist with the placement and spacing of individual flint stones, which were hand laid face down in the agreed style. Dover District Council visited the factory during the production period to assess the flint arrangement and to ensure it met its needs and gave the best possible match to existing flint walls and buildings in the vicinity.

To create the desired finish, the production team hand-picked the stones to ensure they all interlocked together neatly. Once this extremely time-consuming process was complete, steel cages, lifters and pipes were located and installed and the concrete carefully poured over the top of the flint stones to form the wall structures. The following day, once the concrete curing process was complete, the excess sand was washed off and the units were turned using the in-house gantry crane to present the finished article.

Milbank’s modern Sipe batching plant is capable of producing 35m3 of concrete per hour. For this particular project, a standard C40/50 strength-class concrete comprising of 460kg/3 of Portland cement, 1800kg/m3 of mixed aggregates and 40kg/m3 calcium carbonate fines were selected to create the desired finish and achieve the level of structural integrity required.

 

 

Installation and completion

Due to the size and weight of the wall units, with some weighing up to 11 tonnes and sitting at over 5m tall, a complex installation procedure was required involving the use of both 100-tonne and 80-tonne mobile cranes (lifting up to a radius of 17m) in combination with the specialist precast installation team. Due to the access restrictions on-site, short trailers were arranged for delivery ahead of schedule following on from an initial site consultation and the delivery vehicles arrived on a ‘just-in-time’ basis, allowing for the walls to be offloaded directly into position.

Each individual wall was located over projecting steel dowels and cast into the foundations on-site by the main contractor RG Group, a specialist in the retail, student accommodation and commercial sectors of the construction industry. Lined and levelled on shims and bedding, the walls dowel connections were fully grouted using specialist pipes cast into the rear of the structures during the manufacturing phase. The walls were designed with male-to-female connections to act as a shear key, which allowed the walls to act in unison and to reduce individual movement once installation was complete. 

Due to the walls being manufactured and installed as individual units, it was required that the joining sections be hand-filled on-site by the main contractor with matching flint stones to consolidate all units into one flowing piece. Finally, end columns and caps were also manufactured on-site by the main contractor to provide finishing touches to the wall structure. The flint walls now act as a screen to the service area for the main retail block from the roadside, which includes M&S and Next at the Dover St James development.

www.milbank.co.uk

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