Offsite construction: the secret to sustainable building?

Con­struc­tion is awash with sus­tain­abil­i­ty tar­gets, and the cli­mate emer­gency means both reg­u­la­to­ry pres­sures and mar­ket expec­ta­tions are ris­ing like sea lev­els.

The prob­lems are not new, though. Back in 2013, the UK gov­ern­ment pub­lished its indus­tri­al strat­e­gy Con­struc­tion 2025, which set out clear tar­gets for low­er costs (down 33%) and emis­sions (50%), plus faster deliv­ery (up 50%).

With a focus on pro­duc­tiv­i­ty and labour issues, the Farmer Review fol­lowed in 2016, provoca­tive­ly enti­tled Mod­ernise or Die. Among 10 head­line rec­om­men­da­tions, the report chal­lenged the indus­try to invest in R&D and inno­va­tion to sup­port man­u­fac­tured tech­nolo­gies, rather than tra­di­tion­al build­ing meth­ods, par­tic­u­lar­ly in the hous­ing sec­tor.

These off­site sys­tems and meth­ods – includ­ing mod­u­lar and vol­u­met­ric solu­tions, struc­tur­al insu­lat­ed pan­els, plus design for man­u­fac­ture and assem­bly (DfMA) – offer the prospect of build­ing and engi­neer­ing in fac­to­ry con­di­tions with greater effi­cien­cy and less waste, more qual­i­ty con­trol and less snag­ging.

This can make deliv­ery faster, cheap­er, safer and green­er. So, what’s not to like?

Well, any­thing that threat­ens the hege­mo­ny of busi­ness-as-usu­al will encounter resis­tance from the indus­try old guard. When the palette of design options appeared lim­it­ed in the ear­ly days of MMC, off­site solu­tions were tagged as ‘boxy’.

Pigeon­holed as only fit for bud­get appli­ca­tions and projects with mul­ti­ple unit rep­e­ti­tions, MMC became asso­ci­at­ed with no-frills hotels, stu­dent accom­mo­da­tion and pris­ons. While it might be per­fect for schemes seek­ing economies of scale; it is also much more than that.

The suc­cess of Lego lies in its sim­plic­i­ty

Myth-bust­ing is still required. For instance, there is a per­cep­tion that a stan­dard­ised approach to build­ing could stunt the cre­ativ­i­ty of archi­tects when the oppo­site is true, argues Rus­sell Haworth, CEO of glob­al tech­nol­o­gy plat­form NBS:

“Take the exam­ple of Lego; its suc­cess lies in its sim­plic­i­ty. Yet, with­in that struc­tured frame­work, it opens the door for almost infi­nite cre­ative options – build­ing every­thing from Hed­wig, Har­ry Potter’s owl, through to the Mil­len­ni­um Fal­con, the icon­ic Star Wars craft.”

Advances in robot­ics, automa­tion and mass-cus­tomi­sa­tion nowa­days mean com­po­nents can offer almost infi­nite design choic­es, with short­er pro­duc­tion runs. Ver­sa­til­i­ty is boom­ing, regard­less of whether the pri­ma­ry build­ing mate­r­i­al is con­crete, tim­ber or steel.

The result­ing award-win­ning designs come in all shapes, sizes and sec­tors.

In edu­ca­tion, for instance, there are the tim­ber-clad curves of the £4.4m expan­sion to Adding­ton SEN School, Read­ing, designed by HLM Archi­tects and built by Reds10. In hous­ing, the sus­tain­abil­i­ty skills of archi­tects Bry­den Wood won acclaim for real­is­ing the devel­op­ment poten­tial of a prob­lem­at­ic site at Church­wood Gar­dens, Lon­don.

From hotels and health­care to bath­room pods and bridges, off­site appli­ca­tions are up.

For deliv­ery at speed and scale, espe­cial­ly in hous­ing, though, invest­ment is crit­i­cal, too.

Despite a chal­leng­ing start, Legal & Gen­er­al has recent­ly dou­bled-down, announc­ing fur­ther mul­ti-mil­lion-pound invest­ments into its mod­u­lar hous­ing arm. House­builder West­on Group has also sunk £35m into its British Off­site oper­a­tion, cre­at­ing more jobs at a new fac­to­ry along­side its exist­ing facil­i­ty, in Essex.

Even Ikea is get­ting in on the act, part­ner­ing with Swedish con­struc­tion giant Skan­s­ka on its Scan­di­na­vian BoK­lok homes con­cept, which is fight­ing off the flat-pack asso­ci­a­tion in places like Wor­thing and Lit­tle­hamp­ton, in West Sus­sex.

This cre­ativ­i­ty and growth need not come at a cost to qual­i­ty and effi­cien­cy.

Being less labour-inten­sive, stan­dard­i­s­a­tion not only helps dri­ve up qual­i­ty, but also short­ens time­frames, espe­cial­ly when phas­es of work are under­tak­en con­cur­rent­ly in fac­to­ry con­di­tions, with no delays due to inclement weath­er or skills short­ages.

Tak­ing these mul­ti­ple ben­e­fits togeth­er, projects util­is­ing MMC can prove faster than tra­di­tion­al builds and require few­er deliv­er­ies to site, so min­imis­ing neigh­bour­hood impact.

Ener­gy is anoth­er area of poten­tial effi­cien­cy gain with off­site – in terms of embod­ied ener­gy, ther­mal per­for­mance, and decar­bon­i­sa­tion. Wider fac­tors are in play here, though, explains Simon Richards, Sus­tain­abil­i­ty Direc­tor at Sir Robert McAlpine.

“Deliv­er­ing build­ing ele­ments in a con­trolled envi­ron­ment allows us to ‘get it right first time’. This means we use few­er mate­ri­als, emit less car­bon and dri­ve effi­cien­cies. The lev­el of qual­i­ty and per­for­mance con­trol will also help us to dri­ve down oper­a­tional ener­gy emis­sions – so long as instal­la­tion and inter­faces with oth­er trades are cor­rect.”

Ulti­mate­ly, many of the bar­ri­ers to uptake are not archi­tec­tur­al or tech­no­log­i­cal, says Adam San­ford, oper­a­tions lead South East and Lon­don, at South­ern Con­struc­tion Frame­work. The issues are sys­temic and call for rev­o­lu­tion, not evo­lu­tion, he adds.

“Off­site isn’t just cab­ins and doesn’t have to cost more. How­ev­er, tra­di­tion­al con­struc­tion sup­ply chains aren’t geared up for man­u­fac­tur­ing-based solu­tions – a sea change is required. The dire need to decar­bonise the built estate pos­es chal­lenges unique in scale and scope; it also presents unpar­al­leled oppor­tu­ni­ties for mar­ket dis­rup­tors.”

Deliv­er­ing build­ing ele­ments in a con­trolled envi­ron­ment allows us to ‘get it right, first time’

Employ­ing lean man­u­fac­tur­ing tech­niques to min­imise mate­r­i­al con­sump­tion and waste is one such oppor­tu­ni­ty afford­ed by off­site solu­tions. This is a major indus­try con­cern and a crit­i­cal sus­tain­abil­i­ty met­ric, giv­en offi­cial sta­tis­tics that show con­struc­tion, demo­li­tion and exca­va­tion gen­er­ate more than three-fifths (62%) of total UK waste. 

Look­ing beyond mere fac­to­ry effi­cien­cy, the onus is on the build­ing sec­tor to take a proac­tive stance on waste by design­ing for decon­struc­tion, con­cludes James Ellis, Con­struc­tion Indus­try Group chair at the Char­tered Insti­tute of Mar­ket­ing. “The future for off­site needs to embrace the cir­cu­lar econ­o­my – mak­ing sure con­struc­tion con­sid­ers dis­as­sem­bly either as com­plete pan­els for reuse, or through the lay­er­ing of sys­tems to allow for dis­as­sem­bly down to their sin­gu­lar parts,” he says.

This is con­struc­tion reimag­ined as intel­li­gent closed-loop man­u­fac­tur­ing, com­plete with a prod­uct take-back. This is the built envi­ron­ment of today, lever­ag­ing dig­i­tal tools to deliv­er on sus­tain­abil­i­ty goals, for a net-zero tomor­row. This is MMC.

In Bris­tol, plan­ning approval has just been award­ed for an inno­v­a­tive pro­pos­al to cre­ate 15 new low-car­bon, afford­able eco homes, util­is­ing mod­ern meth­ods of con­struc­tion (MMC). But this is not your typ­i­cal off­site build, as it will be con­struct­ed using straw-bale and tim­ber pan­els up on the roof of the city-cen­tre offices of the client, a char­i­ty that works with for­mer­ly home­less peo­ple.

Com­plete with food-grow­ing and shared ameni­ty space, the scheme for Emmaus Bris­tol is being dri­ven by the urgent need to respond to both the hous­ing cri­sis and cli­mate emer­gency. The design approach tak­en to tack­le these sus­tain­abil­i­ty con­cerns is dif­fer­ent, though, sug­gests Craig White, CEO of project deliv­ery part­ner, Agile Homes:

“Agile goes about it by think­ing small and scal­ing fast, to deliv­er hous­ing as if peo­ple mat­tered. We work with MMC in a way that respects peo­ple, plan­et, prof­it and pur­pose.”

Unlike sce­nar­ios involv­ing cap­i­tal-inten­sive invest­ment in big fac­to­ries, Agile’s mod­el of dis­trib­uted man­u­fac­ture opti­mis­es the mak­ing of build-sys­tems for job cre­ation, local­ly.

Prop­er­ties must also be con­struct­ed using renew­able, car­bon-cap­tur­ing mate­ri­als – in this case, pre­fab­ri­cat­ed pan­els made of chopped and com­pact­ed straw for insu­la­tion.

In addi­tion, by unlock­ing land on a rooftop site, the accom­mo­da­tion can be made afford­able for those in hous­ing need, via sim­ple finance options.

The aim is to deliv­er peo­ple-cen­tred solu­tions that are adap­tive to need, per­for­mance and mar­ket demand. Small, but scal­able, the ver­sa­til­i­ty of MMC is what makes this pos­si­ble.

---