Green Building Forum

Home  5  Books  5  GBEzine Subscription  5  News  5  HelpDesk  5  Your Cart  5  Register
Code For Sustainable Homes - Green Building Forum

Hello

Welcome to the Green Building Forum. Reading any of the public conversations is free but if you want to join in the discussions then you need to register first to obtain a code for which there is a small charge. Please follow the link on the left. OR:

GREEN BUILDING MAGAZINE
Get the next four copies of this fantastic magazine delivered directly to your door.
1 year Green Building magazine subscription
Price: £20.00
Discount books available with subscription:


Code For Sustainable Homes

I have been looking through posts on this site regarding CfSH and thought I would share my experience and some advice which hopefully people will find useful.

I am an architect and in the process of building my own house. I am a big fan of the CfSH in principle as it takes such a broad outlook on a property / project, something which all other standards seem to fail in. When looking at finding an assessor I was a bit taken aback by the price quotes, and consequently undertook the training myself to become an assessor as it would also be another string to my bow for my architectural practice http://www.pa-ad.co.uk/.

Through the training and my experience thus far it has become blatantly obvious that CfSH is great in principal but not in practice. I myself am going for level 6 on my project (http://the-old-lemonade-factory.blogspot.com/) but the extra cost involved is quite shocking, hence the reason it will never become mainstream. There are benefits involved such as reduced mortgage rates and exemption from stamp duty, as well as the personal satisfaction, a practical efficient and green home, but these do not help with the upfront costs involved.

I would say that levels 3 & 4 are reasonably easy to achieve, especially if you are going for some sort of ecohome, but 5 & 6 are hard to achieve and will come at considerable financial cost. An essential piece of advice would be to get someone involved who are competent with and have a good knowledge of CfSH at concept / planning stage. Leaving the assessment to the end could leave you with lots of stressful and financial headaches. It will also save you money, as you will be able to pre determine where you can score the amount of points you require and how do this economically - to revisit this afterwards can be very costly and extend the project time considerably.

I would also suggest that serious thought be given to why you want a CfSH rating as it is costly and with the higher levels quite restricting on how you design and build your home. I would even go as far as saying that unless a site is suited towards the CfSH criteria, it may be very hard to achieve a level 5 and impossible to get a level 6.

I hope people will find this info of some use.

Nigel
«13

Comments

  • I can't understand CfSH - why and when is assessment mandatory, and when is it voluntary? What advantage is there in doing it voluntarily?

    BTW Lemonade Factory blog looks like the start of something good. Will be following with interest.

    RobinB
  • I wholeheartedly agree about CfSH. Having designed my new house to be as close to passivhaus standards as possible, using a high percentage of renewable materials, solar PV and solar thermal, rainwater harvesting and no fossil fuel use (other than that needed to generate electricity) I was surprised to see that I'm going to struggle to get level 5.

    The truly daft thing is that I may well end up with a house that is, in reality, zero carbon and with very low embodied energy and water usage, yet only rates level 4, because other elements cannot achieve a high enough rating under the assessment procedure..
  • edited December 2011
    Posted By: JSHarrisThe truly daft thing is that I may well end up with a house that is, in reality, zero carbon and with very low embodied energy and water usage, yet only rates level 4, because other elements cannot achieve a high enough rating under the assessment procedure..
    Interesting. Which elements of the assessment procedure make it difficult?

    David
  • I am not totally clear upon where it is required, but as I understand it, it only compulsory on new builds in Wales I think currently level 3 going to level 4 in the near future. Social housing with funding from government bodies / agencies require it. Also sometimes it is a condition in planning although I have not personally heard of a case. Think if a planning permission is controversial then the applicant committing to CfSH can help their case.

    Financial benefits are from reduced mortgage rates (this is one but there are others http://www.ecology.co.uk/html/mortgages/discounts.htm), exemption from stamp duty (which could be a big saving) and the property will be an extremely efficient one. I don't think that it would add anything to the resale value of your house unless you are going for level 6 (zero carbon) which may appeal greatly to some people. It also acts as a good practice design tool but this has no consequence on actually getting assessed.

    Thanks for the positive feedback on the blog. I have started the story of our project and will add installments each day over the coming weeks. I will also be adding news and images as and when. I have also done twitter @buildzerocarbon and facebook www.­facebook.­com/­pages/­The-­Old-­Lemonade-­Factory/­231090636959395 Will also be trying to get in press etc.

    Nigel...
  • edited December 2011
    Posted By: davidfreeboroughInteresting. Which elements of the assessment procedure make it difficult?

    David
    OK, let's start with the energy/CO2 element. The house is near airtight with MVHR, walls and roof are of timber construction and have a U value of 0.11, windows are passivhaus certified (U value 0.63), doors have a U value of 0.68. DHW is an ASHP, which will also run supplementary UFH on the ground floor. There's no flue or fuel burning appliances. The SAP 2009 percentage improvement DER/TER is 79.61%, which gets a level 4 rating.

    I've played around with SAP to try and get the DER/TER higher than 80%, but cannot get the 100% figure demanded for level 5, no matter what. The daft thing is that the house will have enough PV and solar thermal to meet its total energy needs through the year, I suspect, so will, in reality, be zero carbon.
  • It was mandatory for all new dwellings to have a code rating (even if it was a nil rating); However the Government announced the suspension of Home Information Packs (HIPs) from 21 May 2010 and the requirement for sellers to give a sustainability certificate (either a Code for Sustainable Homes certificate or a nil-rated certificate) to buyers of newly constructed homes was also suspended.

    A Code rating now is as mentioned generally a requirement for Social Housing developments or occasionally a planning condition from Local Planning Authorities for development of a given site.

    Part of the problem for the specific example above is use of a heat pump as the heating/hot water system. By setting the main fuel type as electric, the Target Emission Rate is set much higher, albeit the DER will typically be well below this - commonly referred to as the 'Code 4 loophole'. However The actual DER is still quite a high number compared to say gas or a wood burner for main fuel. The Code 5 target is for a DER of zero, so the higher the start number - the more you need to do to get down to zero.

    Code 6 is for DER of zero + cooking and appliances also compensated for (which aren't considered in SAP).

    The only way to get to Code 6 is for lots of electricity generation - PV or wind typically - and lots of it.

    There is also a requirement for a low Fabric Energy Efficiency target (ENE 2) - This bit is much easier to achieve(comparatively).

    Whatever the wikipedia entry on CfSH might say, Codes 1 to 6 are all still doable I believe, but the ENE1 bit is set as mandatory minimum of L1A 2010 compliance, which equates to around the same level of Code 3 from previous version of the code. In practice though, most people look to achieve Code 3 or better if they do aim for a Code rating (Social Housing more commonly Code 4).

    The code covers a lot more than just the energy and CO2 emissions requirements.
  • jon
    edited December 2011
    I more or less agree with Nigejk: I done as far as CfSH level 5 design and it's not easy to achieve. Level 3/4 isn't too bad. On some sites it would be next to impossible to get to level 6.

    Jon
  • The reality is that there is enough PV and solar thermal to meet the house energy needs, I believe, but the fact that the heating and DHW is electrically powered is the killer.

    I were to fit a dirty, high emission, wood burner, sacrifice all that airtightness for the sake of having a flue and all that entails and use a non-sustainable (in this part of the UK) fuel like wood I could get a higher Code for Sustainable Homes rating?

    Barking mad or what..................
  • When I submitted my planning application back in 2009 I indicated we hoped to build to level 4 or above. It was never mentioned again.

    As the house neared completion I spent a day "scoring" the house against the revised CfSH that had just come out. It was looking good, we could tick lots of the non-building performance related boxes e.g. near a bus route, bike shed in the garden, storm water attenuation etc. etc. When I contacted a company to get the real assessment I discoverd it was no longer required.

    I hadn't heard about the zero rate stamp duty for level 6 but doubt we'd be quite there even with the new PV. If/when we ever do decide to move on I'll see if it's still valid.

    Thanks for the info!

    RobinB
  • C4SH is obligatory for all new-build in Wales; private domestic Level3 minimum.

    As someone said earlier in the post, if you get a 'switched-on' C4SH Assessor in at the beginning, it is not much effort at all, just a bit beyond Building Regs for L3 and L4.

    However, as a post-build exercise, almost impossible, and very expensive, retro-fits cost way more than if they were planned for! :cry:

    Some people don't appreciate that the C4SH also covers the building process as well as the building itself, and is designed to improve the whole construction process. Whether this is sensible or not is open to debate.....?:devil:

    Also, our biggest problem as C4SH Consultants is explaining to small developers/builders, that it is designed for biggish developments, 40 dwellings plus, and does not sit well with a single dwelling construction. There (in my opinion) should be let-outs or exemptions/defaults for self-build single dwellings.....

    Cheers...:smile:
  • Interesting observation about the difference between single house developments and 40 dwellings plus ones.

    On a point of principle I would liek to get to CfSH level 5, preferably 6, but it seems even a small timber passivhaus with as much solar thermal and PV as possible, rainwater harvesting, no fossil fuel consumption on site, low embodied energy, provision for bike storage etc will struggle to get above level 4.

    The idea of CfSH is admirable, but the the way in which it has been defined seems biased against those who want to make a one-off zero carbon house, particularly if they are trying to do this in a community with very poor (read virtually non-existent) public transport.
  • JSH,

    Yes, as you probably realise, you cannot get C4SH L6 with the 'dwelling' alone, you need the other bits around, the Considerate Constructors Scheme, Home User Guides, Ecology Reports etc etc... These are over and extra to a single dwelling, just not worth it.... the C4SH hs been badly implemented in my opinion, but then if you look at who has been 'driving' it, perhaps not that much of a surprise....:shamed::shamed:

    Cheers...:smile:
  • Its bizarre JSHarris I would have thought that your specs sound more than ample to achieve what you are after unless your house is half made of glazing. The only things I can think of are your air pressure which must be under 1.5 if you have MVHR and the cold bridging y value, using the default y value makes it quite a bit more tricky. Have you also put your MVHR in your Appendix Q / special features. Are you using a SAP assessor?

    Sigaldry the problem I am having is with the FEE which I think is incredibly hard to achieve at the level 5 & 6 requirements. I had to pull the SAP workings to bits to find out how to improve mine. Turns out that the cold bridging was the issue.
  • edited December 2011
    Glazing area will be modest and all passivhaus certified. Building is very airtight by design. MVHR and the ASHP together recover around 85 to 90% of the waste ventilation heat. Cold bridging has been designed out and house will be on a well insulated slab with detailed attention paid to the wall/slab joint. Assessment has been done using Stroma FSAP 2009. In all probability the house could be passivhaus certified if I wanted the hassle and cost of doing it.
  • JS Harris for the code assessment bizarrely gas seems to be the way forward. I have been round the houses with my heating systems. I have finally decided on solar thermal with gas boiler backup. Although a gas boiler does bump up the CO2 created it will get you the points for the NOx emmissions POL2. I have even tried the averaging of NOx emmissions but to no avail (and to be blunt the averaging calculation is so far off the mark it is unreal). The POL2 will get you more than 2 points out of the possible 100, so worth it in my opinion.

    I think it is a prime case of where the code is flawed it is pushing you down an avenue that you have to do a particular thing to get points when I believe it is not necassarily the best or greenest solution. I have put so much time and money into getting level 6 I am not going to sacrifice changing to a different heating system. This is also a good example of when knowledge of the code is invaluable at design stage. I spent a long time to come to the conclusions of what is best.
  • I am also using FSAP so may be able to help out. You say you have designed out cold bridging - is this reflected in the y-value you have entered (opaque elements tab at top) / what value is it?, also what FEE value are you getting?
  • Posted By: NigejkI am also using FSAP so may be able to help out. You say you have designed out cold bridging - is this reflected in the y-value you have entered (opaque elements tab at top) / what value is it?, also what FEE value are you getting?
    It's OK, thanks, I have got very low space heating requirements - fabric loss and ventilation loss are already very small - as the house is most probably passivhaus compliant already. T

    The problem is using electricity!
  • Posted By: NigejkJS Harris for the code assessment bizarrely gas seems to be the way forward. I have been round the houses with my heating systems. I have finally decided on solar thermal with gas boiler backup. Although a gas boiler does bump up the CO2 created it will get you the points for the NOx emmissions POL2. I have even tried the averaging of NOx emmissions but to no avail (and to be blunt the averaging calculation is so far off the mark it is unreal). The POL2 will get you more than 2 points out of the possible 100, so worth it in my opinion.

    I think it is a prime case of where the code is flawed it is pushing you down an avenue that you have to do a particular thing to get points when I believe it is not necassarily the best or greenest solution. I have put so much time and money into getting level 6 I am not going to sacrifice changing to a different heating system. This is also a good example of when knowledge of the code is invaluable at design stage. I spent a long time to come to the conclusions of what is best.
    That is a superb example of the flaws in the code! Pushing you to use gas just to get extra points for NOx seems bizarre. If it properly allowed for the offset from PV then perhaps an all-electric house might score more highly, but as far as I can see it doesn't. One issue is that the DHW calculation in SAP is a bit generic and doesn't match well to our needs I've found. I know our DHW requirement and it's about 1/2 of that predicted by SAP (maybe we're just frugal......). This skews the result, too, as DHW is the most significant energy consumer in the house through the year.
  • The code is a compete joke! It took us 7 months (we started in May and got it in December) to get our interim certificate for code 3 and cost us an extra £2000 on top of the assessment fee for no benefit. Pre-assessment is bad enough but an interim certificate for a selfbuilder is completely over the top. The best bit is that Stroma are making the rules up as they go along, as well as the flaws mentioned they also contradict building regs in certain circumstances (e.g. light fittings) and they never give you a straight answer in less than 2 weeks..oh and their software crashes and looses data. Building control (here in south wales) have said that people are now selling plots because the the code is too much grief. A good example of an initiative that was rushed and not properly thought through, shame because it could have changed the newbuild housing stock, instead the big developers will just build the same cr*p but with a few pv panels, a couple of bat boxes and some recycling boxes in the kitchen!
  • Andy,

    I sympathise with your problems.... the C4SH is not well suited for self-build or single plots; it has been designed primarily to influence larger spec-built and main-stream developments. I am not an apologist for the C4SH in any way, but without it, no one is going to drive upwards the standards in domestic dwellings in the UK? Nearly every developer we have met or worked with in the last few years only is concerned with maximising profit at the expense of the people who end up living in their dwellings. They all winge about increased levels of insulation eating into their profit margin....:devil:

    However, once we have explained the aims of the C4SH to builders/owners involved in self-build, for Level 3 it is not much more than Building Regs., and little beyond.

    Perhaps your bad experiences are due to lack of information at the outset, and your Assessor(s) not being fully conversant with SAP and Building Regs?
    I have seen some C4SH pre-Assessments that are rubbish, they bear no relation to the proposed dwelling, and if left intact would lead the owners into a minefield, of retro-fitting and expensive 3rd party reports, that cost money for no benefit other than a paper Certificate! :devil::devil:

    I am not trying to blow our own 'corporate' trumpet, but we try to show our clients the most cost effective way to whichever Level they wish to acheive, and so far it seems to be working.

    Cheers... :neutral:
  • "Corporate trumpet."

    Love it. :bigsmile:
  • Posted By: Joiner"Corporate trumpet."
    Isn't that what BT used when they were making those excessive profits in the 90's :wink:
  • The code is a very expensive road block to building. The only people who seem to like are the assessors and consultants raking in their fees for pointless work and dragging out the time taken.
  • Fred,

    (Tongue_in_cheek_mode) You're not a developer, are you...? :bigsmile: (Tongue_in_cheek_mode off)
  • I'm not sure that CfSH is that tough for developers overall, at least not the big ones. In part it replaces things they may well have been asked to do under S.106 agreements anyway, and the remainder of stuff isn't far removed from what they need to do for BR compliance. Chuck in the marketing advantage they might get by playing up the CfSH rating and they may well view it as profitable overall.

    I regularly drive past a development that stalled when the housing market crashed (the developer just mothballed the site overnight, leaving it as an ugly eyesore for the past couple of years). Recently they've finished a handful of houses and are pushing them hard. The big banner on the main road proclaims "50% more energy efficient homes". I've been down to look at them and they barely scrape through current building regs.................
  • Posted By: Fred56The code is a very expensive road block to building. The only people who seem to like are the assessors and consultants raking in their fees for pointless work and dragging out the time taken.
    It may be a troll but .... If we do not have something of this ilk, how do we push up the appalling build standards we currently tolerate? The house I currently rent is less than 10 years old and the build quality is just awful. I don't think it is the best way forward; a concerted push on quality of build, air tightness, and insulation levels alone would make a huge impact. SAP is a joke; but it is a start.
  • The simplest way to push up build quality would be to remove the current domination of the new house market by cheap and cheerful developers who build crap homes in order to make high profits.

    If we had a new house market like that in Germany, for example, where self-build, or at least customer build to order, is the norm, then there would be consumer pressure for quality. As it is, people have no choice when it comes to a new homes, they either buy crap from Barrats or crap from Persimmon (or one of the others).

    One major problem is that there has been precious little support from the government to encourage self build. This strikes me as odd, as the best way to revitalise the building industry would seem to be to put money into the small businesses that are at the heart of it, via incentives to self-builders. Any incentive that is focussed primarily at the big developers will primarily be used to increase their profit margins, not increase skill levels in the industry and get people into a trade.
  • Wasn't part of the reason the changes to the planning system were being proposed, to make it easier for self-builders? Sure I read that somewhere.
  • edited December 2011
    Posted By: JoinerWasn't part of the reason the changes to the planning system were being proposed, to make it easier for self-builders? Sure I read that somewhere.
    I've read one statement by Grant Shapps alluding to more support for self-builders, but nothing seems to have yet materialised. There's nothing in the planned changes to planning policy that make a significant difference to self-builders, AFAICS.

    If I was a cynical old git I'd think that the building industry lobby may well have intervened to convince government that they should direct help in their direction.............
  • As far as I can tell, the problem with most builds in this country is that the tradesman just don't have the necessary skills nor the discipline to attend to the fine details. Most seem to regard topics such as air-tightness and insulation fitting as something only 'geeks' think about. It seems to be a case of wap it up as quick as possible and what you don't see will be alright.

    It seems to me that the only way to get a house done to a decent spec is to either a) do the construction supervision yourself, though this assumes you know what to look at or b) get tradesmen in from Germany or Switzerland to do the job.

    I maybe being a bit pessimistic but with all the courses, certifications, controls that tradesmen have to go through where is the quality?

    Jonti
Sign In or Register to comment.