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  1. @Triassic We also had a quote suggesting 2 x 350m3 units, and TBH I just rejected as appearing to be unecessarily expensive and complicated. However, it would be interesting to find out if there is a good rationale behind these odd recommendations. The obvious answer is they want to sell 2 x (unit + ducts + installation + comissioning), but it would be worth hearing their justification. If "it's a big house" is the only level of detail they are willing to give, I wouldn't be confident in their design anyway. Re. branch vs radial ducting. In our case, branching was going to be a problem due to our build method & house design. We have: - a warm roof i.e. ducts can't go in loft - the roof beams are steel so can't accomodate a 200mm duct through them - concrete first floor - ducts can't go in the floor This meant a large branching duct would have to run through most of the rooms. We like an industrial look, but that would be too much. Instead we are running the 90mm radial ducts through multiple holes in the roof steel beam webs (SE specified...), which keeps it all out of the way: This was the primary reason for radial. But other advantages over branching that we felt were relevant: - Eliminates risk of cross-talk noise between rooms (which might be small but wanted to be sure) - More control over each arm i.e. room - Continious pipes so no airtightness problems at joints over time - Supposedly cheaper to install (according to https://www.heatspaceandlight.com/difference-between-branch-radial-duct-which-better/ ) Radial is less efficient due to greater internal surface area of the piping, but we didn't see that as a big issue.
  2. We have GFA 350m2, which Enhabit calculated required 378m3/hr on boost, and are going with their recommendation of a single zehnder Q600 (600m3/hr), with radial ducting. I wonder whether the suppliers recommending 2 units are doing so due to additional factors to size e.g. issues with ducting in a 380m2 house over 4 floors? Or some perceived issue with using a larger unit?
  3. N.b. the kingspan panels have to be supported on purlins or rails, which may then need further support, so the 150mm doesn't give you the full required thickness. Though you can leave this open to some extent if you don't mind the internal face. The panels provide little sound insulation (or decrement delay...), so you may want to cover them internally for other reasons.
  4. We are using the KS1000RW Kingspan Quad-Core panels as the outer shell (walls and roof) in our build. A single component that provides insulation, water-tight shell, and a reasonable degree of airtightness (though this will need some additional taping). It is on a heavy steel frame. We are using the 150mm version giving 0.12 u-value. Thermal breaks in the column floor junctions handled with armatherm FFR structural thermal breaks. With a lightweight steel frame you probably wouldn't have such an issue since it could all sit on an insulated slab. The internal face of the panels we couldn't stomach so will be covered to give a deep service void. There are one or two examples of it used on domestic buildings, but mainly modern barn conversions, i.e. they were a panelled shed that someone turned into a house. @Simon Brooke has used the KS1000RW for the roof of their dairy conversion, which seemed to be successful.
  5. On the subject of alternative blocks https://biomason.com/ 'bioMASON’s technology uses microorganisms to grow biocement™ based construction materials. The Company’s products include proprietary manufacturing processes and materials used by licensing partners for incorporation in existing facilities or on-site manufacturing. The strength of biocement™ materials is comparable to traditional masonry, and is used as a green alternative. bioMASON’s products are produced in ambient temperatures using locally available materials. bioMASON enables savings in energy costs and zero carbon emissions.' Looks awesome. Presumably rather expensive. If you are really keen, they just opened a $18M funding round https://www.wraltechwire.com/2019/12/10/rtp-startup-biomason-launches-18m-fund-raiser-lands-first-5m/
  6. Some more block examples ordered by density (not comprehensive and updated last year) https://docs.google.com/spreadsheets/d/1FKs4IIEIqb-KFJl63zsR0uj2BXAnEJMyyQbyeiZNylc/edit?usp=sharing @Oz07 expanded clay examples: fibolite, fibo 850, aglite ultima
  7. I once saw 'mini' spray foam blowing out a brick wall into the street below. Given this is on a major bus route I suspect the mortar on these Victorian buildings was pretty much dust.
  8. I had a brief tour shortly after they started re-excavating, around 2000. A story cited was the sandstone cutting into Lime Street station was being dug at the same time, and at one point the labourers working on the cutting unexpectedly broke through into a dimly lit underground chamber filled with toiling diggers (the in-progress Williamson Tunnels) and fled believing they had uncovered Hell and its dammed minions.
  9. Also worth considering that in the not too distant future there might be some large EV batteries in there periodically. Who knows what chemistry these might have in future, but no doubt there will be guidance / regulations on fire safety relating to EV parking. I suspect for now we'd have a 'no EV under there' rule until the world understands the risks better.
  10. @scottishjohn Yes the plan is for 150mm of either phenolic or kingspan quadcore panels on the soffit, should give about 0.12U. I had wondered about something like a mist system, but needs more investigation. As per it may be a really good alarm system(s) might be more effective. I did once live in a flat where a mattress was set alight in an abandoned flat below, and the first I noticed was the floor under my sunday morning feet starting to heat up. This early warning won't be available with 200mm of concrete.
  11. Thanks all of the comments. Thinking about it today, I think there's flaw that in our case means we can't use the structural topping to lay the UFH pipe. The planks are laid on the bottom flange of asymmetric steel beams in a 'slim floor' style, in order to save height. e.g. (based on shallow-floor designs such as https://www.steelconstruction.info/Floor_systems#Shallow_floors) Since the structural topping doesn't in our case go over the top of the steel beams, the UFH pipes can't go through the beams (without complexity). However, if anyone is ever interested in UFH pipes in hollowcore topping, it does appear that it is (or at least was) tacitly supported by US and Canadian building codes: http://www.healthyheating.com/Concrete-codes-radiant-heating/Concrete-codes-radiant-heating.htm#.XZpJr0ZKhhF The middle one was what i was thinking of. @scottishjohn The ICF floor style is neat and something I would have looked into, but in our case this floor is over an agricultural-use ground floor, which could have vehicles, workshops, storage, etc in and I am very concerned about the effects of a fire down there on the house above. Any EPS in the floor soffit I would expect to last hardly any time before melting. In the EKONECT and quad-deck examples it looks like the EPS in the floor doesn't provide any structural aspect, as that's all handled by the cast/pre-cast concrete, i.e. the EPS melting might not affect overall floor integrity. I suspect had I looked into these in more detail 8 months ago, we might have made a different choice, but we are on course with the hollowcore now.
  12. Our design has a first floor of hollowcore planks (about 150mm thick) with a structural concrete topping (minimum thickness 50mm I think), and we are looking to add UFH. Naively, it seems to me simplest, thinnest, lightest, and perhaps cheapest to have the UFH pipe laid in this structural topping and then make the topping the required thickness above the pipes (60mm?). As opposed to having; hollowcore, 50mm structural topping, then a separate (60mm?) screed with UFH over the top of that. As I understand it, a structural topping over hollowcore is partly to create a smooth level surface, but also sometimes to create a composite floor with the precast planks, which is stronger. My concern is that having UFH pipes in this topping would somehow adversely affect this structural aspect. I know there is general acceptance (on this forum at least) of UFH in structural ground slabs, such as in MBC builds, but what about as part of hollowcore floors? This is one for the SE, but would be keen to hear people's views.
  13. Idealcombi futura, aluminium window with PUR thermal break. Available inwards or outwards opening. Alu clad uPVC can get higher performance than timber (with the right version) if top performance is what you are after. E.g. the foam-filled energyline 91 P from gaulhofer (via ecowin)
  14. For ultra-dense, there's structural thermal breaks like: Farrat https://www.farrat.com/structural-thermal-break-connections Armatherm https://www.armatherm.com/thermal-break-materials/ Which presumably you could just use a few blocks of and fill the spaces between with standard non-dense insulation. I assume expensive though.
  15. Here's a list of prices compiled from BH public posting https://docs.google.com/spreadsheets/d/10mPQ-4HnTuUbiKmQVn3fPPoVkxDMPgRFNvaji4R8USg/edit?usp=sharing Apologies anyone if I've made a mistake on your prices or missed you out. I wasn't hugely systematic. I'm surprised not to see any Green Building Store ones. As @craig says, a simple m2 hides a lot of detail that affects price e.g. ratio of fixed vs opening windows, doors, cills, coated glass, non-rectangular, airtightness level of the model, etc. I suspect the mysterious discount factor also distorts things. @lizzie I'd previously had you at £390/m2 - was that just for alu UPVC and you went for alu timber at £566/m2 in the end? From https://forum.buildhub.org.uk/topic/1820-alu-clad-timber-or-pvc/?do=findComment&comment=26286