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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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    • CommentAuthorlineweight
    • CommentTimeDec 19th 2018
     
    Unfortunately most building projects aren't done by enthusiastic self-builders, sustainability-focussed professional builders, nor benefit from budgets that allow experimentation or unconventional methods.

    So I'm interested in what your experience is of 'builder-friendly' constructions that can reliably produce good results in terms of insulation and airtightness - accepting a bit of compromise on what could potentially be achieved. I think these need to be construction buildups that are widely used, that won't frighten contractors being asked to meet tight budgets, and which are tolerant of non-skilled and imperfect workmanship.

    At the same time, allowing the result to exceed the building regs minimums by some amount.

    For example: timber frame wall constructions often come out as the best bet if you start out with the aim of achieving good u-values. But in the UK (England at least) most general builders are more experienced and comfortable with blockwork walls which means that a timber frame design can push up prices, and in my observation end up being bodged together in a way that compromises many of the benefits.

    So, I thought it might be useful to have a thread where folk could give their thoughts on wall, ground floor and roof buildups that tend to give good results when carried out by a typical general building contractor. All the better if this is based on real-world results/experience.
    • CommentAuthortony
    • CommentTimeDec 19th 2018
     
    Medium density blockwork inner skin lots of insulation outside that 300mm clad with whatever you like, I chose bricks.

    Concrete floors Wood roof

    Passive slab

    3g windows , U<0.1 air leakage < 1
    • CommentAuthorbhommels
    • CommentTimeDec 19th 2018
     
    What Tony says, basically.

    My experience with the extension build:
    Block inner and outer skin, 200mm full-fill cavity w/ ancon wall ties and (wood) cladding on outside.
    Warm roof with glulam ridge beam (wood) and timber rafters
    Slab, passive if you can, otherwise with UFH.

    Builder was happy to build to spec as it was not too far off what he always did and he reckoned that this is what everybody will want in a few years time. I worried about all details regarding airtightness (membranes, tapes), insulation integrity, avoiding cold bridges, window and door fitting etc. Although I have not put a single brick on top of another myself, it still is a lot of work costing a lot of time, which I had at that point. In the end though I know that it was (mostly) built to spec, in the way I wanted. And I must say that the few mistakes happened when I took my eyes off the ball if only briefly.
    • CommentAuthorlineweight
    • CommentTimeDec 19th 2018
     
    Single skin blockwork with EWI still considered less 'easy' than cavity blockwork then?

    I can see that this might be down to the need to use manufacturer-specific systems to fix the final cladding layer (or render) whereas it's a bit less complicated fixing into an outer masonry leaf.

    Maybe also the lack of 'standard' details at eaves and ground.
    •  
      CommentAuthordjh
    • CommentTimeDec 19th 2018
     
    I think this is approaching the problem backwards. A better approach is to try to ensure good workmanship. Details depend on how the project is organized, but:

    - contracts specifying the performance required
    - time for on-site training allocated and attendance compulsory
    - at least one person on site with knowledge and authority to check work as it is done
    - clear & accurate design documents

    Sure some building techniques are simpler/more reliable/more familiar than others but that all depends on what the particular builder is familiar with. Roof construction in Scotland versus England, for example. Timber frame in USA vs England. etc
    • CommentAuthorbhommels
    • CommentTimeDec 19th 2018
     
    @djh, agree to all your points, however it is difficult enough to find knowledgeable and trustworthy people to oversee the build, and in particular for smaller domestic projects like extensions your requirements would drive the price up by a lot. Apart from that there is the issue of enforcement and/or leverage in case things do not go to plan. I guess this is why we are all so fond of DIY?
    • CommentAuthorlineweight
    • CommentTimeDec 19th 2018
     
    Posted By: djhI think this is approaching the problem backwards. A better approach is to try to ensure good workmanship. Details depend on how the project is organized, but:

    - contracts specifying the performance required
    - time for on-site training allocated and attendance compulsory
    - at least one person on site with knowledge and authority to check work as it is done
    - clear & accurate design documents


    In the real world, especially for small jobs, these are all things that can scare builders away and push the price up.

    Even finding a builder who will sign a proper contract can sometimes be difficult.

    I'd love to work in a system where all of the above were standard and were properly implemented, however it's not the reality. This thread is looking for pragmatic approaches to working within the construction industry as it currently is, with the skills it currently has, and in the context of the prices people are willing to pay.

    Also, if some or all of the things you list can be achieved, it doesn't have to be instead of seeking to design in a way that makes it easier for builders to build well. So, yes, have clear design documents, but which describe a design that the builder is already familiar with the principles of.
  1.  
    This is a great question! There is a low probability of me tackling a second self build next year, and if that happens one of my objectives would be to improve built (not designed) u-values and air tightness.

    I have no building experience, so although I say 'self build' I'll be working in the office to earn money and spending minimal time on site and leaving all construction to the 'professionals'.

    If my second self build does come to fruition, the direction I'm currently leaning towards is finding a team with proven results. Last time I used a good builder, but they had never built a house before and didn't have green building at the core of their philosophy.

    If I find a team that has achieved great air tightness, and gives good attention to detail in fitting the insulation etc..., through block work I'd be open to this route.

    More likely I think, is to find a timber frame company that design and install the foundations and frame as a package. I think it would be easier for me to find a company that has already completed multiple houses and achieved good built as results.

    It isn't jut about the builder, it is also about the architect and structural engineer, but the builder has a very big impact as they are the ones that actually put the building up.
  2.  
    Posted By: lineweightSo I'm interested in what your experience is of 'builder-friendly' constructions that can reliably produce good results in terms of insulation and airtightness

    For me its single skin block-work, EWI outside and wet plaster inside
    • CommentAuthorowlman
    • CommentTimeDec 19th 2018
     
    Notwithstanding U values and builder skills, shouldn't the carbon footprint of the materials used enter into the equation.
    •  
      CommentAuthordjh
    • CommentTimeDec 19th 2018
     
    Posted By: lineweightThis thread is looking for pragmatic approaches to working within the construction industry as it currently is, with the skills it currently has

    Then, IMHO, you may as well give up now.
    • CommentAuthorgravelld
    • CommentTimeDec 19th 2018
     
    I think one of the problems here is that different projects attract different sectors of the construction industry. Motivated professionals working in high spec new builds, passivhaus etc are different to your local builder.

    And so it is that us members have different experiences because our projects are very different and so we attract different professionals.
    • CommentAuthorlineweight
    • CommentTimeDec 19th 2018
     
    Posted By: Peter_in_Hungary
    Posted By: lineweightSo I'm interested in what your experience is of 'builder-friendly' constructions that can reliably produce good results in terms of insulation and airtightness

    For me its single skin block-work, EWI outside and wet plaster inside


    Are you, as your username suggests, outside of the UK?
    • CommentAuthorlineweight
    • CommentTimeDec 19th 2018
     
    Posted By: djh
    Posted By: lineweightThis thread is looking for pragmatic approaches to working within the construction industry as it currently is, with the skills it currently has

    Then, IMHO, you may as well give up now.


    Give up on what?
    • CommentAuthorlineweight
    • CommentTimeDec 19th 2018
     
    Posted By: gravelldI think one of the problems here is that different projects attract different sectors of the construction industry. Motivated professionals working in high spec new builds, passivhaus etc are different to your local builder.

    And so it is that us members have different experiences because our projects are very different and so we attract different professionals.


    Absolutely - and many people can't afford to have everything done by highly motivated professionals who focus on high spec builds.
  3.  
    Posted By: lineweight
    Posted By: Peter_in_Hungary
    Posted By: lineweightSo I'm interested in what your experience is of 'builder-friendly' constructions that can reliably produce good results in terms of insulation and airtightness

    For me its single skin block-work, EWI outside and wet plaster inside


    Are you, as your username suggests, outside of the UK?

    Yes - why?
    • CommentAuthorlineweight
    • CommentTimeDec 19th 2018
     
    Posted By: Peter_in_Hungary
    Yes - why?


    Just because favoured building methods vary quite a bit from country to country. So what is easy to get built well where you are might not apply so much in the UK.
  4.  
    If anything surely a EWI clad solid block build should be cheaper than a traditional cavity wall construction? When comparing same U values?
    •  
      CommentAuthordjh
    • CommentTimeDec 20th 2018
     
    Posted By: lineweight
    Posted By: djh
    Posted By: lineweightThis thread is looking for pragmatic approaches to working within the construction industry as it currently is, with the skills it currently has

    Then, IMHO, you may as well give up now.

    Give up on what?

    On your search to find ways of producing good results with average current tradesmen and 'building professionals' without training or extra supervision. TANSTAAFL.
  5.  
    Posted By: lineweight
    Posted By: Peter_in_Hungary
    Yes - why?


    Just because favoured building methods vary quite a bit from country to country. So what is easy to get built well where you are might not apply so much in the UK.

    I was in the UK (England) before Hungary. I've done the bit with English builders - they are no better over here. I don't like cavity walls having had a couple of houses with impossible to stop gales blowing through them. I've done single skin block walls (in UK) and found them cheaper, quicker to build and more difficult to hide the sins.

    But you're right favoured building methods do vary. Over here now it tends to be porotherm blocks or ytong blocks both with EWI to improve the insulation.
  6.  
    There's a good book on this topic that I was browsing today:

    Designed to Perform: An Illustrated Guide to Delivering Energy Efficient Homes
    (full disclosure I've met the author a few times when he was devising this book)

    Extract here: https://www.ribabookshops.com/cms/product/preview/d2pextractforbswebsite.pdf

    There's a ton of site photos illustrating good and bad practice and what to look out for etc. as well as 3D drawn details and thermal modelling but it's all based around improving standard site approaches to building rather than jumping straight in at the passivhaus end of things.

    Arguments on both sides as to whether this is 'rearranging deckchairs' and ignoring the big picture or just a pragmatic approach given the scale of the performance gap and skills shortage; but either way I thought it might be of interest.
    • CommentAuthorlineweight
    • CommentTimeDec 20th 2018
     
    Posted By: djh
    Posted By: lineweight
    Give up on what?

    On your search to find ways of producing good results with average current tradesmen and 'building professionals' without training or extra supervision. TANSTAAFL.


    I'm not looking for a free lunch - just the best one that is possible within constraints.

    If someone is looking to do a project but without the budget to do it with all the stuff that is necessary to get that ideal result, what do you propose they do? Give up on any notion of doing better than 'standard'? Give up entirely and carry on living somewhere even less energy efficient? I'd rather find somewhere in between, that is, do the best that is possible with the given financial resources. Hence the whole point of this thread: look to specify building methods that have the least chance to go wrong, and the least chance to end up costing money that could be otherwise focussed on energy saving efforts.

    If you specify a wall buildup that is likely to be popular with a wide range of builders, then you are some way to getting some good (or any) quotes back. And the more chance you might have a bit left in the budget for those things like a little extra supervision.
    • CommentAuthorlineweight
    • CommentTimeDec 20th 2018
     
    Posted By: Doubting_ThomasThere's a good book on this topic that I was browsing today:

    Designed to Perform: An Illustrated Guide to Delivering Energy Efficient Homes
    (full disclosure I've met the author a few times when he was devising this book)

    Extract here:https://www.ribabookshops.com/cms/product/preview/d2pextractforbswebsite.pdf" rel="nofollow" >https://www.ribabookshops.com/cms/product/preview/d2pextractforbswebsite.pdf

    There's a ton of site photos illustrating good and bad practice and what to look out for etc. as well as 3D drawn details and thermal modelling but it's all based around improving standard site approaches to building rather than jumping straight in at the passivhaus end of things.

    Arguments on both sides as to whether this is 'rearranging deckchairs' and ignoring the big picture or just a pragmatic approach given the scale of the performance gap and skills shortage; but either way I thought it might be of interest.


    Thanks, looks like it could be an interesting book to check out. I'm not sure it's exactly dealing with what I'm talking about here though, which is not so much to do with the details and what happens on site, but which basic constructions to choose at the outset. Or maybe the book talks about that too?
  7.  
    Posted By: lineweightI'm not sure it's exactly dealing with what I'm talking about here though, which is not so much to do with the details and what happens on site, but which basic constructions to choose at the outset. Or maybe the book talks about that too?


    Yes and no. By it's own declaration, "All construction types can achieve high levels of fabric performance with three
    continuous layers of windtightness, insulation and airtightness".

    There's a section in the introduction that splits into the following categories:

    cavity masonry
    concrete frame
    timber frame
    Insulated Concrete Formwork
    SIPS & CLT
    Modular off-site

    with a summary table of the benefits, risks and limits of each. The chapters of the book are then based on each of the above.

    My only criticism is that it didn't really cover what I'm specifically looking at on a current project (precast concrete panels), choosing instead to look at the more common concrete frame with steel infill. The principles are still sound though and a lot of the guidance would transfer across.

    So it's fairly broad but may not give you the definitive 'do this rather than this' as it's aimed at trying to raise the game in (almost) every construction type.
    • CommentAuthordickster
    • CommentTimeDec 21st 2018
     
    We were very very lucky, found builder willing to take risk and had I beam house built. He absolutely loved the method of construction.

    So they are out there.
    •  
      CommentAuthordjh
    • CommentTimeDec 21st 2018
     
    Posted By: lineweightIf someone is looking to do a project but without the budget to do it with all the stuff that is necessary to get that ideal result, what do you propose they do? Give up on any notion of doing better than 'standard'?

    I don't believe it's about choosing the best technique - it's about choosing the best builders and manging them properly. So for an average person I would suggest that their attention should be focussed on avoiding risk, not getting better performance. Try to minimise the risk of sub-standard building. That means choosing competent and well-intentioned builders and if the customer doesn't trust themselves to do that, then they need to pay somebody to do it for them.
    • CommentAuthorlineweight
    • CommentTimeDec 22nd 2018
     
    Posted By: djh
    Posted By: lineweightIf someone is looking to do a project but without the budget to do it with all the stuff that is necessary to get that ideal result, what do you propose they do? Give up on any notion of doing better than 'standard'?

    I don't believe it's about choosing the best technique - it's about choosing the best builders and manging them properly. So for an average person I would suggest that their attention should be focussed on avoiding risk, not getting better performance. Try to minimise the risk of sub-standard building. That means choosing competent and well-intentioned builders and if the customer doesn't trust themselves to do that, then they need to pay somebody to do it for them.


    Well, that's easy to say, if you completely ignore the reality of financial constraints, and/or doing stuff in areas where builders are in high demand and you find yourself forced to choose based on things like whether they'll even reply to an email.
    •  
      CommentAuthordjh
    • CommentTimeDec 22nd 2018 edited
     
    Posted By: lineweightWell, that's easy to say, if you completely ignore the reality of financial constraints, and/or doing stuff in areas where builders are in high demand and you find yourself forced to choose based on things like whether they'll even reply to an email.

    The point is that you can't ignore financial constraints. Neither can you ignore knowledge constraints. If you can't afford to pay somebody to do something because you know you can't do it yourself, then the wise thing to do is nothing. Don't attempt the project until you can afford it; don't start it on a lowest cost basis. We all know whwere that ends.

    And FWIW, I set out on my build intending to get multiple tenders, pick the best and go. Since I didn't get any tenders, I finished up running the job myself. But I already had known I needed to know what I was getting into and that we needed contingency, so we coped. And we were lucky to find good trades.
    • CommentAuthorgravelld
    • CommentTimeDec 22nd 2018 edited
     
    What if you have to do something, e.g. rotten windows? There are other constraints.
    •  
      CommentAuthordjh
    • CommentTimeDec 22nd 2018
     
    Posted By: gravelldWhat if you have to dosomething, e.g. rotten windows? There are other constraints.

    Duh, replace the windows?
   
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