Thursday, September 20, 2007

Code for Sustainable Homes: cracks appearing

Just got back from a two-day symposium run by Nottingham University’s School of the Built Environment. There were a number of very interesting and cogent presentations given mostly by academics, architects and materials suppliers, and unusually for an event such as this, an overall theme emerged which could perhaps be best summarised as Code for Sustainable Homes — Whoaaahh, steady on, not quite so fast.

Many experienced voices expressed disquiet about the turn of events over the past twelve months, ever since the government published the Code and announced that it intended to move all new housebuilding to zero carbon by 2016. In particular the Code’s almost wholesale adoption of the PassivHaus standard came in for questioning: its apparent insistence on mechanical ventilation with heat recovery came in for a lot of flack, as was its insistence on heavy and expensive triple glazing and almost excessive zeal in which it promoted airtight construction. There was a feeling that this represented a degree of over-engineering for houses in a relatively mild (and getting milder) climate, where many people still routinely sleep with their windows open. The event saw the launch of a set of different proposals for low energy housing in Mediterranean climates, but the question of whether these were more applicable to the UK than the German PassivHaus standard was left for another day.

There was also a healthy debate about how best to power these post-2016 homes. The Code explicitly calls for the homes to generate renewable energy to cover their own energy requirements, but it remains unclear just where or how it can be produced. The preferred solution would seem to be onsite, but everyone agrees that many homes will be completely unsuitable for onsite production. But once you accept that the energy harvesting can move offsite, you run into all manner of problems of definition. District heating systems? Shares in windfarms? Or just buying power from a green energy supplier? All are possible, but they are either technically challenging (CHP) or are just another version of carbon offsetting (widely derided).

There was also a good deal of discussion about the water saving proposals contained in the code. The idea is that we should aim to be reducing our water use from around 150lts/day each down to just 80 lts/day at Code Level 6, the 2016 standard. That is surprisingly challenging: even if you fit every water saving device, ultra low flush toilet and lo-flow shower, you still struggle to get below a notional 100lts/day. To get right down below 80lts/day requires on site water harvesting or recycling which again was felt to be fine in principle but the thought of rolling this out into 250,000 new homes a year appears to be fanciful at best. But this is what the code demands after 2016.

Wednesday, September 19, 2007

This is what an Energy performance certificate looks like

Click here

Timber frame fire findings

The London Fire Brigade have come back to me with the summary report of their findings on the Colindale fire on Wednesday 12 July 2006. Highlights include:

• The building was under construction and consisted of a concrete ground and first floor, with the remaining five upper floors solely constructed from timber.

• A fire was first seen at first floor level in Block B4. This is thought to be the fire’s ‘Area of Origin’. Block B4 was part of an ‘L’ shaped building with maximum dimensions 38 metres by 60 metres. The fire’s ‘Area of Origin’ was close to the centre of the building adjacent to the staircase shaft and lift shaft.

• The fire spread rapidly through Block B4 with full involvement and collapse of this building in less than 10 minutes.

• The fire spread by radiated heat to an adjacent building also under construction. The fire also spread via radiated heat to the top floor and roof of the neighbouring Middlesex University Halls of Residence. There was also damage by radiated heat to thirty vehicles parked in Aerodrome Road and to the “P.N.C. Building” located in the Hendon Police College on the opposite side of Aerodrome Road.

• As a result of the fire approximately 180 construction workers were evacuated from Block B1 and Block B2 and approximately 100 students were evacuated from the Middlesex University Halls of Residence. In addition, an unknown number of staff were evacuated from the Hendon Police College complex. No injuries were sustained during the evacuation.

And as to cause? The report makes these comments:

• The most probable source of ignition of this fire was a carelessly discarded lit cigarette at first floor level in Block B4.

• The rapid fire spread was not due to an accelerant and was consistent with the fuel present, i.e. High surface area compared to mass of construction timber, eighteen metres high with virtually unrestricted airflow.

Further thoughts and speculation

The key word here is accelerant. If there was an accelerant used (i.e. petrol or even paper), then we have a case of malicious arson. The report is quite clear that no accelerant was used. But my first thought was: How the hell can you tell anything about the cause of a fire, if the building has been burned to a crisp in just ten minutes? And why the speculation about a discarded cigarette? Presumably no one has come forward and said “Oh yes, I dropped a fag in B4 just before the fire took hold.” We would have heard. And unless there was a lot of readily combustible material lying around, like plastic sheeting or waste paper, a cigarette would not cause a timber frame building to catch fire. Whilst the fire spread may be consistent with the fuel present (i.e. timber and foam-based insulation), the initial ignition of the fire is more problematic. There surely had to be some intermediary element that could transfer fire from a lighted cigarette to a timber wall. That doesn’t necessarily mean it was a deliberately placed accelerant, of course, but there must have been something easily ignitable present and what that might have been isn’t mentioned.

Finally, it appears that there were builders on site but they were evacuated from buildings BI and B2, not B4 where the fire broke out. This suggests that B4 was quiet. That’s handy. And if you wanted to set fire to a block of flats under construction, where would you go about starting it? The fire's area of origin was on the first floor close to the centre of the building adjacent to the staircase shaft and the liftshaft. At the bottom of a staircase and liftwell? Just the spot to turn a small fire into a conflagration in seconds.

It’s enough to make you wonder, if nothing else.

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How good is greenhouse gas data?

In order to make sensible decisions about how to reduce CO2 emissions, you need good data on what those emissions actually are. In essence, you need to create a robust accounting system, built out of units of CO2, not to mention other greenhouse gases. There will be both a profit and loss account – energy in use – and a balance sheet – embodied energy in buildings and plant. In an ideal world, these carbon units could be linked to money and you could apply a cost-effectiveness filter across everything.

But the basic data isn’t yet in place. Or, to put it another way, there are still wide disparities in attempting to work out just how much CO2 is being emitted.

Take electricity consumption. It’s a complex beast because it is derived from a variety of sources, some carbon rich (oil, gas, coal) some almost carbon-free (nuclear, renewables). Plus it gets distributed over huge areas and undergoes transmission losses and power station inefficiencies. How can you attribute a single figure to the CO2 content of electricity? Well, we do. It is routinely rated in the UK as emitting 0.43kgCO2/kwh, just over twice as much as mains gas, and this is the figure used to calculate the CO2 emissions of electrical appliances, including heat pumps.

A long and involved thread on the AECB forum looked into just how accurate this 0.43 figure actually is. It turns out it was set in 1998 at a time when the CO2 content of electricity was falling because of the dash-for-gas. It never got down to 0.43, but it was thought that this was a good figure to use because, over a decade or so, it was hoped that the CO2 content might fall to somewhere close, and so it was a good basis to plan electrical installations on. The current figure, according to DEFRA, is actually 0.52 and, worryingly, it’s been going up not down in recent years as coal fired power stations have been coming back on line. This figure also takes no account of transmission losses, nor of embodied energy costs in power stations, nor extraction/transportation costs of coal and gas. It could, in reality be much higher than 0.52kgCO2/kWh. Some comments even set it above 1.00kgCO2/kWh. How can we hope to make sensible planning decisions about whether to install kit like heat pumps unless we can be sure that the raw data on electricity use is accurate?

It is yet another puzzle in this complex web we are weaving. It seems to me to be an increasingly important issue that is not being given the attention it deserves. We are being expected to make ball-achingly expensive decisions about future CO2 emissions and energy paybacks, but there are still huge question marks hanging over the accuracy of the data we are using.

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Are DIY electrics still allowed?

I am in the very early thought process stage for building my own home. I have every intention of carrying out as much of the work myself as I possibly can, and this ranges from ground works to electrical installation, plumbing etc, etc.

However, the recent changes in legislation now mean that I have to employ someone else to do what I could do myself the day before the changes came into force.

To comply with this new legislation, my thinking is that I need to be approved under the "Competent Persons Scheme", and therefore, I need to know exactly what qualifications I need to gain, and what my next move is once I have the qualifications. Is it purely a case of gaining BS7671 and the like ?

It seems very odd that as a "layman" I can visit my DIY store or similar merchants and purchase all of the equipment I require to install systems, but I can't actually do anything with regard to fitting them.

Can you please clarify what the situation is.

Ian Thorley

Mark Brinkley, Author of The Housebuilder's Bible writes:

It wasn’t until 2005 that electrical work came under the auspices of building control in England & Wales. Part P, as it is known, doesn’t actually state that only competent persons are allowed to carry out electrical work: rather it suggests you have two choices. Firstly, you can elect to have a suitably Part P qualified electrician undertake the work for you and sign it off as having been carried out in accordance with BS7671. Alternatively, you can apply to have the electrical work inspected — and hopefully passed —by your local authority building inspector, or an agent acting for them. This, in theory, allows DIYers to undertake their own electrical work, in the time-honoured fashion, but adds in a measure of quality control that wasn’t previously there. If this work was being carried out as part of a larger project — i.e. building a house — then there shouldn’t be any additional charge for inspecting the electrics, though this may be at the discretion of the building inspector.

However, not every local authority is happy to undertake electrical inspections. Some of them have hired qualified electricians to undertake this new workload, others haven’t bothered and are instead insisting that all electrical work is undertaken by suitably qualified electricians. I suggest you make some enquiries to your local authority building inspectors and find out where they stand.

If they insist on you using a qualified electrician, and you still wish to undertake the work yourself, you then have a further two choices.

• One is to find a Part P electrician who will mentor you through the job, do some inspection and sign off the job as their own. They do exist. One who works regularly with selfbuilders across the land is Ben Addison.

• The other is to undertake the training yourself. There are various places you can do this training. One such is Trade Skills 4U.co.uk, who offer a range of courses suitable for your needs at a cost of around £1,500. This must include a City & Guilds 2381 qualification to show you understand the essentials of BS7671, and a further qualification for Part P Domestic Installers. Having successfully completed the courses, you would also need membership of a certifying body such as The Electrical Contractors Association in order to be able to sign off your own work. It would probably cost you around £2,000 for the qualifications and a year’s membership. However, at the end of this process, you would also have a very sellable skill. If you really enjoy electrical work, maybe this is what you have been waiting for!

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Vat reclaim reveals selfbuild figures

I have been taking at look at the UK’s selfbuild VAT reclaim figures. These are a key statistic, used to measure the size and the health of the selfbuild market where, uniquely in Europe, new homebuilding is zero-rated for VAT purposes. What I have managed to glean from the Revenue & Customs are new figures from March 2004 to August 2006; I already have figures for six years in the 1990s, so there is enough data here to make some comparisons.

In the first period, 1993-99, the average number of reclaims under the DIY reclaim scheme was 10,593 per annum. In the second period, April 04 – Aug 06, this was 10,810, a 4% increase, possibly not statistically significant.

However, the average size of each reclaim has grown dramatically, from £4,166 in the 1990s, up to £6,547 in the Noughties sample. A whopping 57% increase.

What the figures reveal

Firstly, they don’t really tell you the size of the selfbuild market. The only people that make DIY reclaims are non-professionals who aren’t registered for VAT and who buy materials on their own account. Therefore there will be lots of selfbuilds that never appear in these figures. We have to guess how many more, but you won’t be far out if you were to add 50% to the numbers — i.e. around 15,000 per annum.

They do tell you that the number of selfbuilds isn’t really growing. In fact earlier figures that I’ve seen also confirm this. The number of DIY reclaims has hovered between 10,000 a year and 12,000 a year ever since 1984 when VAT first became chargeable on building work.

What about the dramatic increase in the amount being spent? I can see two obvious reasons for this. Firstly, inflation in building materials, which has been growing steadily over the past few years. Secondly, selfbuilders specifying more upmarket materials, in line with housebuilding generally. Granite worktops, underfloor heating, hardwood floors, etc.

Finally, one fact is revealed in the latest figures which I haven’t seen before. Around 15% of claims are disallowed. That seems an extraordinarily high figure. I know the scheme is somewhat complex to understand, but nevertheless that’s quite a figure. I don’t know whether this 15% represents a lot of wholly rejected claims or whether it’s people wrongly claiming for unallowable parts of their build costs — probably a bit of both. The figures I have used for the amounts claimed excludes the rejected claims.

If you want to know more about the DIY VAT reclaim scheme, the relevant page is here. Please note, this scheme only operates in the UK.

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New urban design in practice



I made my second visit to Upton this week. For those of you not in the know, Upton is the new Poundbury. Sort of. It’s an urban extension (fancy modern term for a housing estate), tacked onto the edge of Northampton, and it’s full of weird and wonderful homes. I was there as part of a Princes Foundation seminar group and the guiding hand of this group is evidenced all over the development, though its much more diverse than Poundbury. Although at first glance it looks all very traditional, there are modernist schemes here as well and Bill Dunster’s Zed factory is hard at work on one corner delivering what they claim to be the first Code for Sustainable Homes Level 6 homes onto the market.

Only the southern side of the development is complete, the rest is still very much a building site. However, enough is there to give an impression of what it will be like when all 1200 homes are all done and dusted. In many ways, it’s the complete antithesis of selfbuild. Like Poundbury, the whole scheme is about urban design and master planning, building model settlements where everything is thought through and everything hopefully functions smoothly. It’s just as much about social engineering as it is architecture and consequently it all has a rather prissy, manicured feel to it.

But behind the glossy veneer of this exemplar development, most of the work is being undertaken by warts–n-all housebuilders and developers, and it’s not an easy site for them. Kim Slowe, of Cornhill Estates, one of the Upton developers, who cut his teeth at Poundbury, gave a very interesting presentation to the group and was quite upfront about the problems encountered. “Whereas homes in Poundbury sell for between £230 and £260 per square foot, up here in Upton we are lucky to get £165. It’s a very different social mix and quality building is a much harder sell. It’s challenging.”

And whereas the scheme density, the parking restrictions and the pepperpotting of social housing throughout the site doesn’t appear to cause any problems in Poundbury, these issues have all become thorns for the developers trying to woo in private buyers at Upton. By way of example, Slowe indicated that theft of building materials was an ongoing issue on this site. “It’s all very well using lead-lined canopies over the front doors, but the lead keeps getting stripped off.” Just around the corner from Slowe’s houses, I walked straight into the evidence that this was indeed the case – see image.

The verdict on the success or otherwise of Upton will be some time in coming, but you have to admire the vision and drive which enabled it all to get out of the ground. Do take a detour to go and visit the scheme and make your own mind up.


BTW, it’s not very well signposted. It’s on the western fringe of Northampton, next to the Sixfields football ground, the home of Northampton Town FC. Set your sat nav for NN5 4EZ and it should take you to Upton Square, the pulsing heart of the place, right next to the brand new primary school.

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Do we need new housing?

Here in the East of England we are well used to seeing plans put forward for mega amounts of new housing. The usual justification for this is that the economy is expanding fast and that we need new housing to provide space for all the new jobs being created in the region. That, plus the hope that more new homes will keep a lid on ever increasing house prices.

There is, perhaps not unsurprisingly, a close correlation between the number of new jobs being created and the number of new homes required. The ratio seems to be set at around 9 jobs to 10 new homes. The East of England Plan, now two years old, suggested that we would be creating 421,000 new jobs by 2021 and that we would be needing 488,000 new homes to meet the demand created by these new jobs. Since then the numbers have been slowly rising and today we have a report circulating, as reported in the Cambridge Evening News, that the number of new homes we need in eastern England has shot up to 613,000, presumably extrapolated up from 550,000 new jobs.

What no one ever talks about is just what these projections are based on. The East of England is a prosperous area and it’s enjoyed good rates of economic growth for decades. Presumably, these rates are being projected into the future and a percentage point here or there in the projected growth rate results in there being x thousand more jobs and x+0.1 thousand more homes. What you never see discussed is the fact that new houses are themselves creators of new jobs, and hence economic growth.

How can this be? Most new jobs in Britain are in the service sector. As the population grows, the service sector has to expand to keep pace. Each new household brings with it demands for teachers, doctors, nurses, shop assistants, bus drivers, car mechanics, gardeners, jobbing builders, estate agents, hairdressers, office cleaners, you name it.

Another way of looking at this thorny issue is to realise that whilst new housing is an engine of economic growth, it’s an incredibly inefficient one. Let’s hazard a guess here. I reckon ten new homes are needed to fill the vacancies created by just two new jobs resulting from local businesses expanding, and the other seven new jobs result from looking after the residents of the ten new homes. Consequently, the bulk of our economic growth results from drawing people into the region, not from newly-won business deals.

It’s time we took a long deep look at the methodology used to make these projections for both new jobs and new housing. Our aim in the 21st century ought to be to make the existing economy function better, not just expand it for the sake of expansion.

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Find green homes in the UK

Whilst people may argue about what exactly constitutes a natural house, they can no longer have any excuse for not knowing where they are located. Have a look at this fascinating link

Thursday, September 13, 2007

More on the Timber Frame Fires

My musings over the precise causes of the timber frame fires last month have been noted by the UK Timber Frame Association (UKTFA). Yesterday, I was invited to talk over the issue with Stewart Dalgarno who works for Stewart Milne, one of our two timber frame giants, and who is currently chair of the UKTFA.

He reckoned I had underestimated the amount of timber frame apartment building that is going on. Stewart suggested that as many as 30% or even 40% of the medium-rise apartment market was now being constructed in timber frame and this accounted for 300 or 400 sites at any one time across England and Wales. As far as he was aware, there had never previously been any fire damage on the scale seen at Colindale last summer, since when it’s happened three more times, which is what caused me to raise suspicions that these events are not mere accidents, or even isolated cases of arson.

From the UKTFA perspective, the good news is that, thus far, developers have not been put off by the fires and that order books this year are healthily ahead of last year. It is one area where the speed advantages of timber frame really does have major attractions, because you can’t sell any part of an apartment complex until the whole building is complete, and this remains a strong pull for the scheme financiers.

He also went to great length to show that they were addressing the issue of fire hazards during the construction phase. No one is suggesting that medium rise timber frame is a fire danger once completed, but it does present some unique challenges whilst it is being erected. A report examining the causes of fires and methods of prevention is being finalised and should be published in the next few months, to be followed by a series of training seminars aimed at the construction industry.

It transpires that there is usually only a relatively short period during which a timber frame structure can be put to the torch. Once the walls and ceilings are lined, the building is effectively compartmentalised and the risk of fire is greatly reduced. So one of the key initiatives Stewart is suggesting is that, on sites identified as high risk, the lining process is moved up the critical path as far as possible so as to minimise the length of the time spent in the vulnerable panels open, insulation in phase. Ultimately, he sees the industry moving over entirely to closed panel systems where the linings are done off-site, effectively removing this period of added risk. It may well be that the recent fires will end up accelerating this process, which many already see as inevitable in the longer term.

In the meantime, attention is being paid to tightening up site management and security procedures and ensuring that timber buildings aren’t left open for many months, as seems to have been the case at Colindale. Reports on the circumstances and causes of the three more recent fires are still awaited. In the meantime, there is little more anyone can do but speculate.