Jacob Austin 00:00:00 Hi all Jacob Austin here from QS.Zone and welcome to episode 94 of The Subcontractors Blueprint, the show where subcontractors will learn how to ensure profitability, improve cash flow and grow their business. Today's episode, number 94, is all about innovation. And now we're not talking the buzzword bingo variety you hear at glossy conferences, but real nuts and bolts methods that are already reshaping how packages are procured, sequenced and paid for on live UK construction sites. And to compile this, I've been neck deep in research, including white papers from Brea, case studies from Kier, Lange, O'Rourke, Mace's and some pilot schemes under the UK government's MMC framework. And this is something that I've had particular experience of in the past, using some new technology that has caught me out. So I wanted to boil down some of the innovations that I've heard of into some practical details for you to think about. So this episode is your crash course in six breakthrough construction techniques, plus some contractual and commercial tweaks. You might need to stay profitable if these land in your inbox, so I hope you enjoy the show and as ever, if you are new, then please do subscribe for more user friendly advice on all things subcontracting.
Jacob Austin 00:01:36 So here are the six things that I've looked at. Category one RMC in the form of 3D volumetric modular mass timber superstructures including CLT and glue Lam robotic rebar and 3D printed concrete. Digital reality capture using drones to feed into BIM. Level three smart offsite MEP pods being plug and play plant, risers and bathrooms and hydrogen ready construction plant. Some very low carbon kit which could be hitting sites from 2026. And I'll dig into these in a reasonable amount of detail and flag up some of the risks for you as a subcontractor. And we'll finish up with a bit of a checklist that you can use at Tender Stage. With the current focus on MMC. Modular construction has seen a rise, but it has also seen a couple of casualties along the way in the form of main contractors focused entirely on modular units which have gone to the wall. But in spite of that done well, modular builds can be a great success, and for good reason too, because we're not just talking bathroom pods, but entire bedrooms, corridors, even lift shafts built in a factory, shipped to site and then just craned into position like giant Lego blocks.
Jacob Austin 00:02:53 So overnight, vast portions of the build just come together. And in a clear case study. Vision modular built 1500 volumetric units for them, which were installed at Croydon's ten degrees towers as opposed to a traditional build. Kier were able to cut their install programme from 20 months down to 12, which meant a 30% reduction in prelims and a great saving on snagging everybody's favorite, which was down 80% when contrasted to a typical project. Now, if you get involved in modular build, sending lights to a factory to construct to factory tolerances, and in factory conditions, it completely changes the game for your cash flow. Because we're talking of starting on a Monday and immediately needing to install interfaces and hold ups in interfaces can create a big problem, because you could be holding up an entire production line and therefore all the other trades required with just a minor delay, and then the tolerances are much more precise. The modular walls have got their studs in the same position from like unit to like unit, and you're expected to install your first fix to the same millimetre perfect precision.
Jacob Austin 00:04:04 You've also then got the split of work that is built on site versus work that's built in the factory and the interface. There can be even trickier to because, say, as a ground worker, you've often got a degree of tolerance as to where a service penetration needs to go or a drainage pop up needs to appear. But if we're talking of ten stories of modular build or with interlocking downpipes in the exact same position, then your spigot connection needs to be pinpoint precise to receive that with the exact same degree of tolerance. This isn't a situation where ten mil out doesn't make a difference. This is something that can't be changed once the units have gone into manufacture, so setting out needs to be checked and checked again. If your work involves working in a modular unit, and perhaps you've got some kind of design that feeds into that finished modular site, then it's even more crucial that you get that design nailed on and right with good time to feed in to that modular build program. Design freeze is brutal because once units are on the shop floor being built, even tiny changes can be eye wateringly expensive because, again, you're potentially holding up an entire production line to make changes.
Jacob Austin 00:05:16 The golden rule for modular is that modular love certainty. You can build certainty in a factory, but you can't build a 70% complete design that still needs developing. And so in design terms, we're harking back to a time when people actually used to fully design a job before they put a spade in the ground, not build it and update the drawings later. Method number two was mass timber structures, and we're talking cross laminated timber or CLT. In 2024, CLT demand reportedly grew 24%, according to the Structural Timber Association. It's helping Maine contractors to meet embodied carbon regulations, and it does offer a faster install than a more traditional build. Clients also like it for the biophilic exposed timber look, bringing nature indoors. It is faster to install than a more traditional frame structure, and because the finish can be left exposed internally as a double saving in time and prelims, which will benefit the whole job. For example, on a 90,000 square foot office building, the CLT install was completed five weeks faster than the concrete frame that was considered as an alternative.
Jacob Austin 00:06:29 But there is risk involved. Moisture whilst the site is coming together is a big issue, and insurers are now demanding documented weather protection measures for CLT installers. So if you're working on the facade or the roof, then your installation is that weather protection and causing a delay could invalidate your insurances. One for you to check your policy for before you start taking on a site. Acoustic performance can also be an issue. A CLT floor can drum. So if your responsibility see, includes forming penetrations. Then you may need acoustic collars to make sure you're not creating an acoustic weak point. And they may even need onsite testing to check that they're working properly. Another thing that we have in the UK is supply chain volatility with CLT, because 80% of CLT that we use is imported. Foreign exchange swings can hugely affect the price of CLT. And there is actually a specific CLT index because of that volatility. The other thing that is an impact is the haulage of that when it's coming from abroad, which can of course be unreliable.
Jacob Austin 00:07:38 Remember the comedy of the 2021 Suez Canal obstruction, which carried on impacting global freight for months after it? And of course, our good old friend. Industrial action. Fuel strikes, haulage strikes, border police strikes, all of which have the potential to cause a disaster. I'm not saying it's going to happen, but it's one to keep your eye on jobs that are already in delay can be a dangerous place for subcontractors. When the contractor knows they're already losing money, then they may be looking for any opportunity to get their hands on some. So if it happens. Remember my regular reminder on collating accurate records as soon and as often as you can? Now here's some slightly left pieced examples. On the A9 Perth bypass, an autonomous cage tying robot was used to install reinforcement bars, which reduced labor by 45%, and the robots tied 98% of its work in accordance with specification. I feel the need to know what the 2% was, though, because you expect a robot to do things right first time. It is like a moving computer, after all.
Jacob Austin 00:08:47 And we've also got a 3D printing boom and a company called cardboard printed 160 square metre pumping station shell. In just three days they wasted next to no concrete with it and they had basically no formwork to put the building together. There has also been an on site pilot to deliver 46 printed homes in Lancashire. It has some advantages because you can lay intricate geometry without the need for bespoke formwork. You place the material where you need it and of course the printer doesn't fold in sick or have to go to their 800th auntie's funeral on a Friday afternoon. It still is a curious thing though, because there isn't a building control inspection form for extruded concrete spaghetti. So the team building the homes in Lancashire had to prove that there building worked, but it essentially was just like a cavity wall, two layers, insulation in the middle. And then the u-value was verified by heating the home up like a hot box to test the energy loss. Every corner was rounded to 150 millimeter radius, and that meant that the nozzle could run continuously and it actually did away with cold joints.
Jacob Austin 00:09:59 These kind of technologies actually might be a positive that could offset some of the labor shortage that we keep hearing about within the construction industry. It seems like there's some way to go with 3D printed buildings themselves, but some questions to ask yourself. If you're going to work on a site where the walls are 3D printed, how consistent is the finish going to be? Concrete can slump in low temperatures, so what tolerance do you need to work to if you're fitting up to it? How are the fixings going to take to the concrete wall? Do you need to do pull out tests to make sure your regular method works? And how does your work interface with the prospect of 150mm radius in every corner of every room? Now, you've heard me speak about BIM level two before, but there's a new concept that can be used alongside BIM called digital twins. This concept is kind of what it sounds like. A digital twin is like a live replica of a building that integrates the sensor data from the various systems within it, and that means that owners can visualize building performance in real time and run simulations on it, which can include things like how an office restructure might affect the performance of the building.
Jacob Austin 00:11:11 But this technology can also be used during the build, having smart sensors on equipment and structures that could feed into the BIM model for progress tracking and predictive maintenance. Potentially receiving an alert if a structural element shows some unusual strain, but makes use this technology using drones, which were flown out nightly whilst the tradespeople at left site to measure the progress and to update the BIM model to show in real time what had been built and where. This gives some incredibly accurate progress monitoring, but it also gives super accurate QA. It enables things like clashes to be spotted the very next morning, not a month later. So it reduces the impact of errors within the build. But what it also enables is to pinpoint a specific date on which a defect occurred. So if you've installed some pipework after a position. Then the next morning, once the BIM model has been updated, that out of position pipework can be flagged up and corrective action taken. It also means that whilst it's fresh in everybody's mind, who was working in what area, the person or the gang whose install isn't correct can be easily identified and made to go back and correct their own defective work.
Jacob Austin 00:12:21 Now let's say that that pipework that's been installed has got some missing insulation, so it's losing too much heat. Well, we now have the very real prospect of being able to identify exactly when the insulation was installed or when the pipework was installed, and the insulation wasn't. Rather. So the contractor has now got the ability to look at the records and dish out a perfectly evidence to charge. And let's say that you gave the sign off that that work was complete and the ceiling got boarded up. Well, the rework involved are putting that right can now be laid at your door and backed up with BIM and drone footage to evidence it. So this means that your QA procedures need to be on point. And the same, of course, with your setting out to prevent those clashes from occurring in the first place. Don't be surprised also, to see a percentage of your valuation held back pending on verification in the twin model. Now, because that valuation is verified like that, there's no longer the opportunity to talk up the amount of work that you've done.
Jacob Austin 00:13:19 But also it should mean that you shouldn't be short paid either. That nightly progress check should mean that there's no quibble whatsoever over how much work has been done. Now, the next piece of kit that's worthy of a mention is the smart meep pod. I've seen these used myself in the past in a couple of different scenarios. Firstly, an offsite manufactured MLA system in which essentially sections of duct were fabricated with a carrier system around the outside that carried pre-wired containment and pre plumbed pipework. This was then bolted up to the ceiling and a matter of three days we had a fully functioning first fix completed down a really, really heavily serviced This corridor and the install is absolutely pristine. We just wouldn't have been close to achieving that quality, and certainly not in that tight time scale with a fully on site installation. The other thing that I've seen done super effectively is the use of bathroom pods for things like student accommodation. Not a lot of space gets given over to an en suite in a student accommodation, and that makes them notoriously difficult to get perfect.
Jacob Austin 00:14:26 You've got so much service going on in there and the finishes to fit around them, and so they can become particularly tricky to get right. They're places where day worksheets galore would be signed with snagging bits of damage, and you compare that to an absolutely pristine pre finished pod that just gets craned into position with absolutely everything working, all the finishes looking perfect and ready to be locked off and forgotten about. It's a no brainer for the contractor, but it has much wider applications as well. On Balfour Beatty Royal Sussex Hospital they fitted over 2200 pods, which cut hot works hours on site by a million as they made use of fully wired risers, plant room skids and even plug and play energy centers. Now the risk with these is much the same as we mentioned earlier with the volumetric modular kit, and that the tolerances for them is next to nothing. So if you're going to tie into one of these, you need to be absolutely bang on, or you wait until it's finished and fully installed so that you can connect into it at no risk.
Jacob Austin 00:15:33 These are the kinds of conversations that you need to have with the contractor, so that you can avoid picking up the tab for clashes and non compliances. And finally, let's speak about hydrogen plant because JCB and FPT industrial have running prototype 20 tonne excavators that use hydrogen combustion as their fuel source. And we're likely to see them hitting sites sometime during 2026. This is a big coup to help contractors hit government procurement policy requirements of cutting embodied carbon by 30% by 2027, and you're likely going to see main contractors asking for hydrogen plant to be on site. These are incredibly green pieces of kit that, rather than CO2, are just going to discharge water as their byproduct or their exhaust. But it is expensive currently looking at being 30 to 40% more than the typical diesel alternative. It's also going to mean a change in how fuel gets stored, because hydrogen can be considerably more dangerous than diesel or petrol. And at the moment there are only five UK green H2 hubs confirmed in 2025. Delays in delivery of hydrogen could mean standing plant something nobody looks forward to, but this is the kind of green credential that could easily win you brownie points and set you aside from other tenderers if you're able to adopt it.
Jacob Austin 00:17:00 Okay. well, that concludes my moment of geekery on all things new technology. But before I tune out a couple of thoughts on how to protect yourself, if you crop up on a site that is using some of these techniques. Design freeze dates. These are going to be all the more critical working with anything offsite manufactured. The Free State triggers factory release, and if you miss it and you've got something important to feed into it, there can be really big costs involved for variations off site. So you need to be super proactive about your design, and you need to be really clear on the dates that you're working towards so that you don't miss them. A lot of this kind of work is completed off site, so it's vital for your cash flow that you can get paid for that work. We're talking GCT clauses 4.18 and neck for option X 22 for MMC. You need to get to know them and make sure that they're triggered in your contract. Interfaces and tolerances are everything. When you're working with off site build.
Jacob Austin 00:18:05 Dimensions need to be checked and double checked. You need to have a rigorous QA policy, and your installers need to know the score up front. They need to be getting it right first time so that you're not spending a fortune on rework. The transport of some of this kit is really vital as well. So if you're involved in some kind of offsite manufacture, perhaps you're buying in prefab kit as part of your subcontract works. Remember your insurances. We're talking transit storage and even on site insurances that might need to be greater values to cover the additional risk involved. And a final thought just on hydrogen we don't know how the market's going to treat hydrogen, how in-demand it's going to be and how the supply might increase or decrease over time. So you need to think about how risky it is price wise. Do you need to insist on a particular fluctuation for hydrogen fuel? Perhaps this is something that you want to go open book on just to make sure that you've covered the risk. All of these things can eat your profit margin.
Jacob Austin 00:19:07 So give it some thought before you commit to it. I hope you've enjoyed today's slightly unusual episode of the Subcontractors Blueprint. My mission with the show is to help the million SME contractors working out there in our industry. If you've taken some value away from today's episode, I'd love it if you'd share the show and pass that value on to somebody else who'd benefit from hearing it. And of course, subscribe yourself if you haven't already. Thanks for tuning in. If you like what you've heard, then please do find us at www.QS.zone for more information. You can also shout at me on all your favourite socials at @QS.zone again. Thanks again. I've been Jacob Austin and you've been awesome!
