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Moonshine

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Everything posted by Moonshine

  1. Moonshine
    Thanks, what i am proposing is the insulation above the deck is there to achieve the required U-value (150mm PIR), and 100mm mineral wool insulation between the joists is for acoustic reasons (aircraft), as below I am not trying to 'double' up the thermal performance as seems to be main rational for the hybrid roof, however this is more a by-product of the insulation being in there for acoustic reasons, to absorb some sound energy. Are you saying that for a true warm roof the cavity has to be completely void / no significant difference in temperature across its depth? If the acoustic insulation in the cavity had very poor thermal properties, would there be an issue? An alternative could be the rolls of mineral wool insulation between the joists could be laid out to cover 75-80% of the ceiling area, so that in the 20-25% area gaps there was enough thermal weakness that the heat from the room below would heat both sides of the mineral wool insulation negating the risk for a temperature difference and condensation?
  2. Moonshine
    I may have play and see how that looks
  3. Moonshine
    The floor tiles have been an absolute pig to get hold of, first of the suppler sent the wrong one, second they sent the right ones out But, on about 11-12 of the tiles one of the corners got damaged in transit, so they are sending out another box, so assuming they arrive intact i will have more than enough, even with the wasted centre line layout, as i have got all the ones with the corner knocked off.
  4. Moonshine
    Thanks, my understanding of the hybrid system, is as long as dew point occurs in the top layer if the thermal insulation (e.g the warm roof PIR), there isn't an issue, though very happy to be corrected though. I am planning an internal wall leaf of 140mm timber stud with mineral batts, with 25-50mm PIR internal to the studs.
  5. Moonshine
    It does me, and there is an off centre window above it. However hopefully mitigated by a thin cabinet (20cm) with integrated sink, going up the left hand side, as below;
  6. Moonshine
    Good job you showed me this as it clarified the dimension measurement, with the floor to ceiling height used for volume calcs (e.g. 2.4m), where i was using the floor to floor measurements (e.g. 2.7m), that was worth half a SAP point!
  7. Moonshine
    Nice, these are available here https://www.bregroup.com/wp-content/uploads/2019/08/SAP-Conventions-version-8_1-from-01-September-2019.pdf One of things i was struggling with as the value of the thermal bridge of a flat roof with a parapet wall, as the default Ψ-value in SAP 2012 is 0.56, with no approved value. However i found the BRE Certified Ψ-value (W/mK) of 0.046, for the construction i am wanting to use. https://www.bregroup.com/certifiedthermalproducts/product.jsp?id=3594&thermalId=817 A significant reduction as there is 40 linear metres of this junction. With use of BRE Certified Ψ-value's in key areas rather than the default / approved values of SAP 2012, the HTB is down to 22.2 W/m2K. It can probably go lower. If i can get the HTB is down to 10 W/m2K using BRE Certified Ψ-value more, that gives me a SAP of 84.4. Nearly there......
  8. Moonshine
    We tried the diamond and it didn't look quiet right, almost making the room seem narrower. The centre line in the middle of the room was my preference, with larger cut tiles to the sides, rather than the narrow strips or tile near the wall.
  9. Moonshine
    Thanks, i have also found the attached documents, which gives examples of where the bridges are. SAP_OCDEA_nher_technical_bulletin.pdf ZCH-Thermal_Bridging_Guide.pdf
  10. Moonshine
    About to lay tiles in a narrow WC, and not sure about the layout. One has center line in the middle other has a whole tile, as below I have a preference, but interested in others thoughts. Not helped as the WC is slightly off center
  11. Moonshine
    Ah now this is something that i have been missing as i wasn't calculating HTB manually, and left FSAP to do this automatically. Time to put in some actual accredited values for the thermal bridges, anyone able to provide guidance on this?
  12. Moonshine
    The roof is all 'flat / 1:40 fall' which i could put PV on, but i am pretty concerned about putting PV up there due the potential for leaks and costs. I have put in a s 1Kwp solar system in the calcs, which gets the building to a SAP of 85, though really not wanting to go down the route of solar. So it looks like the solar does have a big effect. I am considering using a ASHP, which doing the calcs swapping out the boiler actually raises the TER, to 25 and lowers the DER to 18, so all good on that front however the SAP result is still at 81 / 83, still some tinkering to go.
  13. Moonshine
    Having a look at the calcs there as an assumed air permeability rate of 15 m3/hm2, which is to high. I have reduced this down to 5 m3/hm2, which is a conservative estimate as looking to get it lower than this. It may need to be is i use a MVHR. DER is now 20 with a couple of other changes, EPC of 81 and 80 (Efficiency / Impact), so i need to have further look and the SAP document more and see if its the building design or the calcs.
  14. Moonshine
    Well when i thought i was getting somewhere, i have hit a brick wall. After putting all information in i end up with a EPC of 76 and 73 (Efficiency / Impact), which is quite surprising. Also the DER is 27, where as the TER is 17, so its miles over. So the question is, what is the problem with the house design, or how i have entered the information. U-values as follows; Walls - 0.17 Floor - 0.12 Roof - 0.12 Windows - 1.4 Do these need to be reduced, or are they in the right ball park for a decent EPC? One thing i have noticed in one of the reports is that the space and water heating requirements is nearly 18,000 kWh's per year, based on a 89% efficient gas boiler for CH and water. That seems very excessive, and could it be an indication of an error of input information?
  15. Moonshine
    i am resurrecting this thread as i am going through this process, very simple question to start (i couldn't find a user manual for the software). In the dimensions, i am presuming that the areas are the building footprint including external walls, and the 'total living area' is the internal habitable areas (no garages) not including external walls (though for ease including internal walls?) Also my house has a flat roof, does this mean i need to tick the room in roof box? Edit these are internal areas in regards to a flat roof, the room in roof box should be unticked Some really good guidance as below; https://www.bre.co.uk/filelibrary/SAP/2012/SAP-2012_9-92.pdf
  16. Moonshine
    That's my nightmare scenario! ?
  17. Moonshine
    o.k, that is interesting as in general resi mortgages i thought that a offer has a shelf life of up to 3 months.
  18. Moonshine
    i am not sure i get this, are you saying that the ceiling boards on the resilient bars going to run to an existing ceiling / joist that isn't resiliently mounted?
  19. Moonshine
    SoundBloc, expensive because its got "acoustic" in it.
  20. Moonshine
    Yes in terms of surface density / mass, 16.0 kg/m2 vs 12.6 kg/m2, though at a cost of space (an extra 10mm) and labour fitting an extra layer of board. Or you could put a 19mm thick Gyproc plank up there , at 15 kg/m2, heavy!!
  21. Moonshine
    Cheers @jack, also by the act of the mortgage already being borrowed against, does that mean that its 'enacted' and less likely that your mortgage offer may be withdrawn at a later date. Worst case scenario would be to do half the build on your own funding, just to find that your mortgage offer was withdrawn to build the remaining half.
  22. Moonshine
    ***** pedantic mode ***** Only if you are going from 9.5mm wallboard to 15 mm SoundBloc, and only in surface density/mass. Surface densities/masses below 9.5mm wallboard: 6.3 kg/m2 12.5mm wallboard: 8.0 kg/m2 15mm wallboard: 9.8 kg/m2 12.5 mm SoundBloc: 10.6 kg/m2 15 mm SoundBloc: 12.6 kg/m2 ***** pedantic mode off *****
  23. Moonshine
    i like to tinker to see where things stand at the moment so i have already started on a FSAP 2012 file, will be interesting to see how things work out. Interested to see that there is a U-value calculator that i can put in the proposed constructions. That is a very good shout on the 2 year minimum term, as i had not considered it.
  24. Moonshine
    Make sure at the perimeter of the room you leave a small gap to be filled with a acoustic / flexible mastic. This also allows the plasterboard to flex on the resi bars
  25. Moonshine
    Use these to avoid kinks on bends https://underfloorparts.co.uk/product/cold-forming-pipe-bend-form-supports-underfloor-parts/
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