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Green Building Bible, Fourth Edition
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    • CommentAuthordelprado
    • CommentTimeJan 9th 2018
     
    A thought following the durability of airtightness thread which is very interesting, surely the ideal building is indeed a masonry one, but single skin, with those thick clay blocks like porotherm, covering with as much EWI as necessary?

    Clearly any cavity construction is stupid and hard to detail, while timber frame has to rely on too many tapes and membranes and what not. And wood fibre plus masonry will be ultimate in sound proofing?

    I note that Germany appears to build predominantly with solid wall an EQI, whereas Austria is mostly timber.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 9th 2018
     
    How much overlap would you like in a Venn Diagram :wink:
    • CommentAuthorborpin
    • CommentTimeJan 9th 2018
     
    Posted By: delpradowhile timber frame has to rely on too many tapes and membranes and what not
    'Traditional' TF maybe. My next project will be TF, Icyenne internally and a teacosy of EWI over the whole of the outside; flat roof, Metal Web joists. Not a tape to be seen. Oh and I will clad rather than a brick or block skin.
    • CommentAuthordelprado
    • CommentTimeJan 9th 2018
     
    Haha its a diagram I'd like to see Steamy!

    I just can't see downsides to single block. Sound absorbing (wood fibre) and mass (concrete block) so perfect for acoustics, and cos the wall is warm great thermal mass?
    • CommentAuthorgyrogear
    • CommentTimeJan 9th 2018 edited
     
    Posted By: delpradoI just can't see downsides to single block.


    +1

    me neither :smile:

    we are in N. France, single blocks, massive floors, EWI, warm roof, extensive s-facing Low-E DG, walk-out basement.

    It is 10°C today,10/10 overcast, we have 19.6°C in the house, with no heating on.

    (will stick the wood stove on for a couple of hours later, for TV factor...)

    (All of my efforts are directed at my (inherited) unfinished crawlspace...
    (which keeps the basement somewhat nippy).
    (but we don't live in the basement)

    gg
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 9th 2018 edited
     
    How about lack of accuracy/quality control, embodies energy, reliance on 'skilled' labour.

    If you went to pick up your new car and you found it half built, but a promise that at least the paint sprayer was going to turn up next week, without fail, and as soon as he was done the man with the wiring loom will finish off his job, you would be pretty upset I suspect.
    But that is what a self build block house seems to be like.

    A factory built timber frame one does seem to get assembled and finished a lot faster.
  1.  
    Posted By: SteamyTeaA factory built timber frame one does seem to get assembled and finished a lot faster.


    Yet, in North America where timber frame is the norm, very very few are factory built. Most are build on-site using fairly simple tools.

    Paul in Montreal.
  2.  
    I think Steamy makes a very good point on being able to guarantee the outcome on your chosen method (whatever that may be). I don't feel I achieved as good an outcome as I should have with my specified construction method.
  3.  
    Posted By: delpradoClearly any cavity construction is stupid and hard to detail, while timber frame has to rely on too many tapes and membranes and what not.


    I have a portal timber I-beam framed house with external OSB racking. It has 350mm Icynene internally and 50mm Rockwool externally. It doesn't have any membranes or tapes and achieved an average air tightness of 0.47ACH and wall and roof U values of 0.1W/m2K.
    • CommentAuthordelprado
    • CommentTimeJan 9th 2018
     
    Peter - I bet that performs poorly acoustically though?
    • CommentAuthordelprado
    • CommentTimeJan 9th 2018
     
    Steamey - thats why I thought single skin was easy-ish, whereas to do it properly with a cavity would be really hard. Thick single skin is much more idiot proof
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 9th 2018 edited
     
    Posted By: Paul in MontrealMost are build on-site using fairly simple tools.
    Yes, I was watching my aunt's neighbour have a TF extension done when I was in Halifax, NS.
    They seemed to get nowhere in the month I was there, then it got cold.

    When I lived just outside Harrisburg, PA, the neighbour had their house taken away, a new one delivered, built and finished, all within 6 weeks. I never remember more than about 6 workers on site at any one time either.
    • CommentAuthorgyrogear
    • CommentTimeJan 9th 2018
     
    Posted By: SteamyTeain Halifax, NS


    generally in such northern latitudes, the problem with winter builds, if they overlap the holiday season, is how to integrate the thermal mass (not to mention the rain, dear...)

    gg
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 10th 2018
     
    About on a parallel with Bordeaux.
    Gander is about the same as me.
    They have different weather in winter though.

    Are we still convinced that adding mass to a building is a good thing. Thought that myth had been dispelled for good.
    • CommentAuthordelprado
    • CommentTimeJan 10th 2018
     
    interested to hear why the purported benefits arent real or if they are why they are of no benefit steamy :)
  4.  
    <blockquote><cite>Posted By: SteamyTea</cite>Are we still convinced that adding mass to a building is a good thing. Thought that myth had been dispelled for good.</blockquote>
    I thought that finished up as
    If the building is permanently inhabited then mass is good because of the thermal stability it gives
    If the building is intermittently inhabited then mass is bad because it takes too long to heat up.
  5.  
    Posted By: delpradoPeter - I bet that performs poorly acoustically though?


    Not that I've noticed but I think that is probably difficult to determine overall. I guess it would depend on your location and we live out in the sticks so we haven't found that a problem.
    • CommentAuthorjfb
    • CommentTimeJan 10th 2018
     
    I can see one downside to single block if you are doing the work yourselves - they are heavy! I know which most brickies would rather do.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 10th 2018
     
    Posted By: Peter_in_HungaryI thought that finished up as
    No, it finished up as there is more than enough mass in 9mm of plasterboard because it not all about the specific heat capacity, thermal conductivity comes into it as well. It is the conductivity that introduces the time element, not the mass.
    • CommentAuthortony
    • CommentTimeJan 10th 2018
     
    That is not right thinking

    I like the additional comfort that heavyweight construction brings and the additional ability to store solar gain for long periods of time. This also reduces summer overheating problems.

    We should call it mass as some dislike the term thermal mass
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 10th 2018
     
    Posted By: tonyThat is not right thinking
    It is very much right thinking as it is based on the material properties and their interactions.

    Posted By: tonyI like the additional comfort that heavyweight construction brings and the additional ability to store solar gain for long periods of time. This also reduces summer overheating problems.
    You have no evidence for that and it is especially hard to compare two buildings.

    Posted By: tonyWe should call it mass as some dislike the term thermal mass
    Or call it thermal inertia.

    It is so hard to shift some ideas that have become ingrained in society, even when they are wrong.
  6.  
    <blockquote><cite>Posted By: tony</cite>This also reduces summer overheating problems.</blockquote>

    but not benefit in an extended period of hot weather. Certainly our concrete floor contributes to our overheating problems - afternoon sun heats floor, floor then gives off heat in the evening making it harder to cool the room when outside air temp has dropped.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 10th 2018 edited
     
    Posted By: Simon Stillafternoon sun heats floor
    it is probably heating walls and furniture as well, all depends on the angles and room layout.
    • CommentAuthortony
    • CommentTimeJan 10th 2018
     
    Key there is external shading and not having too much South and west facing glass, my house is cool for three weeks in very hot weather and warm all winter.

    It is not right to listen to what makes life easy for a tradesman

    Evidence for discomfort, Victorian terrace generally 15C in the house in the morning in winter, modern TF 1980’s gets down to 7C on similar winter mornings both with heating off overnight
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 10th 2018
     
    Posted By: tonyEvidence for discomfort, Victorian terrace generally 15C in the house in the morning in winter, modern TF 1980’s gets down to 7C on similar winter mornings both with heating off overnight
    But they are not the same design with the only difference being being the mass. They may have different air changes an hour, different wall to window ratios, different U-Values, different perimeters, different roof construction, different local climates, different heating regimes.

    It is akin to saying that a large old Range Rover only costs £1000 a year to run and a new Prius costs £2000 a year to run. It does not take into account the mileage they do, the depreciation, servicing, tax, insurance etc.

    It is not evidence, it is anecdotal, which just means no data.
    • CommentAuthordelprado
    • CommentTimeJan 10th 2018
     
    Although clearly if anyone has any problems with overheating it’s shade you need a mostly aprobpem
    Of glass. Hunk of the hick stone buildings in the med getting beaten down with sun all day and shutters. That’s thermal mass and shade and hey are wonderfully cool inside
    • CommentAuthorbarney
    • CommentTimeJan 10th 2018
     
    A friend of mine has a steel framed house near Toulouse - this being flat roofed with big overhangs and a lot of glass walls and sexy rainscreen cladding. It has steel panel walls with about 200mm of polystyrene insulation and about 600mm in the roof deck. Windows are well shaded and triple glazed (but a significant proportion of the wall area) - building is effectively up on steel stilts but does have a thick concrete floor suspended on metal deck

    It's next to an old farmhouse (owned by the same family) which is local vernacular with pitched roof, pretty massive walls of local brick and small windows (currently DG aluminium)

    Having spent time in both houses, you wouldn't easily discern that one is inherently cooler in summer or colder in winter - but for sure the energy use is significantly different

    I'm with ST on this one - mass is not necessarily a good thing - thermal inertia is more important

    Regards

    Barney
    • CommentAuthorgyrogear
    • CommentTimeJan 11th 2018
     
    Posted By: barneymass is not necessarily a good thing - thermal inertia is more important


    but I suspect that the respective proponents of either term are actually referring to the same thing, viz. flywheel effect.

    Statements like *THIS* do not do much to help...

    "In building design, thermal mass is a property of the mass of a building which enables it to store heat, providing "inertia" against temperature fluctuations. It is sometimes known as the thermal flywheel effect.[1] "

    Therefore per Wiki, "thermal mass" is an "effect", whereas two lines previous it was a "property"...
    https://en.wikipedia.org/wiki/Thermal_mass

    gg
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 11th 2018
     
    Except you can get a higher storage capacity for a given volume, and a slower release time with a lighter weight material.
    If you compare concrete and timber you will see what I mean.
    SHC concrete is about 0.8 kJ/kg.K, spruce is about 2.3 kJ/kg.K
    Density of concrete is about 2.8 kg/m^3, spruce about 0.9 kg/m^3
    Thermal conductivity of concrete is about 0.6 W/m.K, spruce about 0.18 W/m.K (direction of grain makes a difference, so gives some design flexibility)

    So timber can hold more energy per °C temperature difference, absorbs and releases at a slower rate and weighs less than concrete. It also has less environmental impact than concrete production.

    Now I am not saying that you just need to swap out a 100mm concrete slab with 100mm of spruce, it is a lot more subtle than that as you need to work out what you actually wish to achieve, and what limits you are willing to work with.
    But just adding mass is not the answer and never has been.

    Sometimes it is really hard to shift ingrained idea and old working practices, but if you just sort though the material properties you will probably end up with a better designed house.
    • CommentAuthordelprado
    • CommentTimeJan 11th 2018
     
    Was anyone talking about "mass" per se, though, I was certainly referring to thermal mass, and thinking about stuff like wood fibre boards.
   
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