Roundtable: How will changes to Part L impact design?
A panel of experts, chaired by The AJ sustainability editor Hattie Hartman and invited by Comar, discuss the thorny issues of indoor air quality and building performance
Revisions to Part L are due to go into effect in October 2013. The changes will address new dwellings, non-domestic buildings, retrofit of existing buildings and performance compliance. For new dwellings, the proposed regulations require a mandatory fabric performance standard and related changes to SAP and SBEM calculations. For non-domestic buildings, an aggregate approach means that the fabric target will vary according to building type.
Hattie Hartman Thank you for coming everyone and a particular thank you to Comar for hosting us. I’m going to turn over to Lynne Sullivan for a few minutes, who is chairing the committee that is looking at revisions to Part L, and she’s going to give us an overview and highlights of possible things coming down the pipeline.
Lynne Sullivan So there are two aspects really, which is 1) the standard and 2) a new methodology. We decided on this Aggregated approach; which is basically to set a target for different types of buildings. The Part L timescale is more relaxed, so generally what we were putting forward was going to be less contentious because it’s a fairly modest increase and, as you facade guys know, technology is moving on. For the designer, a modest increase in performance is becoming easier to achieve because of the products in the marketplace. One of the big issues is ventilation: as you get more energy efficient in the fabric, then you have to consider ventilation. Admittedly that’s more of an issue in domestic buildings, but the same principles apply in non-domestic buildings. As you get more airtight, you have to be really careful to get the right air change rates.
Tom Kyle We recently did some work with the Technology Strategy Board, which did a year-long study of a housing scheme that we built. Only about half of the houses used their mechanical ventilation systems correctly. It was a failing on the part of installers to put them in properly, the sales team who didn’t know how they worked and the tenants who didn’t know how they were supposed to be used. Nobody cleaned the filters and so the whole process, from beginning to end, just didn’t work. All the residents were either getting mould in their homes or they were opening windows and the whole thing wasn’t working. So clearly there’s a huge amount of education to be done.
Paul Hinkin With all of this, it comes down to user-centred design. The problem is that we get so fixated on the tech and so fixated on the performance parameters and everything falls down because nothing is simple enough, transparent enough and focused on how it will be used by the average Joe or Josephine! The performance gap is in the way we design solutions for users.
Tom Kyle With increasing airtightness, if you have moisture management problems and you’ve got mould all over your walls, it’s quite obvious; whereas if you turn your heating on and open all your windows, nobody knows, there’s no way of measuring that unless you’ve got some way of metering or you get a huge energy bill.
LS Actually, it’s in schools that there’s some really good evidence, where the air quality’s been shown to be really poor and they’ve recognised it because they’ve realised that students aren’t performing well or people are falling asleep.
Marc Levinson That’s quite prevalent in healthcare as well. How many hospitals do you walk in and it’s baking hot, freezing cold, or all the lights are on because nobody’s tasked with turning them off? We recently looked at a building (not one of ours) that is only about three years old and the energy consumption is already double what the design targets were. There are all sorts of reasons for that – a lot of it to do with some of the procurement routes as well, about who’s paying the utility bills and how tenders are evaluated. We should be looking at lifecycle costing, but of course capital cost is still dominant in the public sector, even though that’s not the official line.
Hari Phillips Having the opportunity to go back to your buildings and see how they’re performing in practice isn’t something we get many opportunities to do. But, the education of people that inhabit the buildings is critical as well. We provide the Home Manual as part of the Code and we assume that people have read and understood it.
Marion Baeli There are some architects who do a put all the utility and ventilation on one board and it’s really diagrammatic; how you get hot air, cold air, hot water. It’s so simple and I think the wall-mounted A1 board or even A3, has to be the solution because when everybody’s gone out, they have the property, there’s nobody to ask any questions and you don’t need to dig it out from under the boiler.
Tom Dollard That’s something that Part L could stipulate; it could say one year down the line, two years down the line; you go and do the tests and check that the MVHR is working and that’s how you get your Building Regs sign-off. Compliance should be based on the later stage and not at the design stage.
Alison Davey We would welcome something like that. I’ve not heard of any facades in a single project where Building Control have said, ‘Sorry, this is not compliant. Go back to the drawing board.’ When we go >> through the tender process we work closely with architects throughout the country with value engineering, and we try and achieve the new U-value that’s requested and then somebody comes out of nowhere with a ridiculous price and you know that they’re saying, ‘Yes, Y achieves X’. We know it doesn’t but they go with the cheaper option, and that’s a big issue which should concern Building Control.
LS Actually, Tom, you raised a really interesting issue. In terms of Building Control’s inspection regime, everything stops at practical completion and hand-over point. That said, the move to soft landings and the realisation about the importance of the commissioning process suggests that real completion is later. As far as I know, there are no precedents. Although, again, in the context of the Building Regs Advisory Committee, I know this has been something we’ve banged on for years about. What it means is a whole new raft of responsibility for building inspectors to come back later and recognise that a lot could have changed in a year of occupation, so it would mean a major overhaul of the Building Act. That’s not impossible: the MP Andrew Stunell brought in a piece of primary legislation under a private members bill, the Sustainable and Secure Buildings Act. It did allow for Building Regulations to be made for the purposes of sustainability, so it wouldn’t require primary legislation to do that.
PH In our project for the Catholic Agency For Overseas Development (CAFOD), we tried to set a rule about simplifying technology to the lowest possible level. We now go back there once every six weeks, either to show it off to potential clients or to see how they’re doing. Because we all think that we’re going to deliver this perfect solution and it never works, it’s always sub-optimal. Somehow we need to find a way of being able to refine the bits that are sub-optimal, or accept the fact that all we do is roll out a standard product, which is like a car that’s been designed and is just replicated across the country regardless of context and I don’t think that’s the right answer. But those are really the two paradigms; choose one of those two.
PH What you could do is, you could just make a call tomorrow that every building has to have a great big sign outside it, which is changed once a year, that says how much energy it used in the previous year. I mean, that’s all that needs to happen because then the pressure of shame will cause change. The pension funds have probably had the most significant influence on what gets built in the UK since the second world war and nobody ever shines a light on them and says, ‘What are you doing?’ So the first thing is to actually just shine that light and say, ‘You’re investing our money, we’ve seen what’s happened, these assets have to be safe and secure and therefore you have to demand a level of performance from the people who are building them for you.’ They have to demonstrate that the performance criteria that were set at the design are being achieved.
LS The Cabinet Office are now introducing Soft Landings, which I think could be quite a game changer. Anyone who’s building buildings that they might want to lease to government offices or public offices – and that’s 40 per cent of non-domestic buildings – they’re likely to have to use Soft Landings. Soft Landings will be mandatory for the entire public estate from 2016.
HH It’s a good first step.
PH The ‘starchitect’ sphere defines so much of how the profession sees itself and how it behaves and even what gets built: expert clients take the view that they want to buy an iconic piece because it will get them planning permission, even if it is poorly performing design.
ML We’re talking as though they’re mutually exclusive; a choice between a really nice building or a high performing one. Maybe that’s part of the problem.
PH We should be demanding that our leadership [RIBA] spends money on building a body of knowledge to allow us to demonstrate to clients that we add value. Until we do, our profession will continue to become less and less relevant, less well paid and less well respected. If the environment you build can help achieve efficiency gains, like 10 to 15 per cent reduced absenteeism in passively conditioned versus actively conditioned offices, then apply that across hospitals, schools, everything, then there’s a massive leap in the performance of UK plc and a body of knowledge we can take abroad and sell – and we desperately need some products to go and sell abroad.
MB In a paper I presented at the Passivhaus conference a few weeks ago, I compared three houses; the retrofit, the Passivhaus and the Decent Home Plus; one with insulation and one single-glazed Victorian, same street, same layout, same everything. We monitored the houses for a whole year, so we have accurate comparative data. The non-retrofitted house, with the income of a two person household on £14,000 per year, which is pretty much the average (in 2009, anyway), will hit fuel poverty in 2020. The Decent Home will hit it in 2030, the passive house, never. This is where we’re heading. Before we leave this issue of the performance gap, this is the one that just keeps nagging away.
HH Marion mentioned the idea of coming back a year later and tying that in. Are there any specifics about how to build that into the process?
AD I think they need to have a test case that goes forward legally, where the building hasn’t achieved what was proposed. That would be a key driver because we are a country of lawyers, aren’t we? Once that happens, it gives us a story to tell to the contractor when we try to maintain a specification.
HH We’ve talked about building performance. What about airtightness and indoor air quality, which relates to what we’re saying here in terms of creating better places. Any observations on indoor air quality?
MB I was speaking to an RSL who owns nearly 5,000 properties and he said their number one issue to resolve is condensation and humidity, because they’ve changed all the windows to double-glazed. Even if they have trickle vents, everybody shuts them off or blocks them up. Condensation is a very big issue!
PH It’s going to be the next wide-scale building failure, isn’t it? It’s going to be the next scandal.
George Legg It’s very tricky. The architectural profession and building physicists don’t know enough about the heat and moisture movement through the building envelope, especially with internal insulation. Brick is not a sealed envelope, it’s a permeable material, so you’ve got moisture coming from the outside and you’ve potentially got moisture coming from the inside too.
HH Does anyone else have any other issues they’d like to raise?
TD We have accredited construction details and we have the standards of Class E acoustics robust detail exactly. I was wondering whether there’s any demand for good thermal bridge details and almost standardised levels of detail that can be rolled out in some way or at least a handbook, that is compliant with the Building Regs, that builders and other contractors can get their head around, so the whole construction industry can get up to speed with these details and start building.
LS In the 2010 Building Regs it was suggested that this is the way forward; that we could have these standard details. But the Department for Communities and Local Government has moved away from them. There’s a revival of interest at the moment, focusing on this performance gap, so I think you make a really good point. Working with robust details is not something that has destroyed design innovation for architects. When we’re doing Passivhaus, we more or less have to work out those junctions ourselves. If we don’t have them as defaults, we have to work them out. We’re working with critical details in mind from the earliest moment, so it’s not a big constraint on architecture, it’s just another tool in the tool box. But it would be good for architects not to feel threatened by this potential new world.
TK Well, it’s already here. The Energy Saving Trust did accredited and enhanced details back in 2006 which we still use, although you can’t roll it across all projects and there aren’t steel-framed details. You have to take it off in the concrete and there are all sorts of problems with them, but it just needs an upgrade. Do the same again, it’s still there and have it signed off on site. That’s how you’re meant to do it: you’ve got the diagram, you give that to the builder. Then they sign off that they’ve done this and, again, it would help architects and take it right the way through the site.
Subscribe to AJ for £3 per week
Subscribe today and receive 47 issues of the magazine, 12 issues of AJ Specification and full access to TheAJ.co.uk and the AJ Buildings Library
Are you a student?
Students can subscribe to the AJ for £8 per month or £1.60 per week! Click here to start receiving the most recommended magazine for architecture students