jfb

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About jfb

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  1. jfb

    Internal blockwork walls

    Why would you use thermalite for anything other than external walls for insulation value? Medium density better for fixing to, sound absorption and fine to go off slab. I suppose they are lighter for the poor Brickie!
  2. jfb

    Heat and sound insulation

    How thick can your walls be? How much insulation are you hoping to have under your floor? Thinnest bang for your u value buck in masonry build is probably single skin blocks and ewi. Cavity wall is possible but to get a decent level of insulation to you are looking at 200mm cavity and so a wider wall
  3. Jude, I would second what Dave has been saying. Find out and give us details of what results you got for your air tightness test and what the specification for insulation values was. Without these figures it is hard to offer advice. The air tightness test result should be in the form of X m3/m2h @ 50 Pa. X being anywhere from 10 (terrible) to 0.6 (very air tight).
  4. I'm in the market for something similar and am worried about noise levels - Crofter are you using it in continuous trickle mode or full blast? Looking at the spec it suggest a noise level of 21db on trickle mode and 45 db on boost. Is it only when it goes into boost that you hear it?
  5. jfb

    Type of foundation backfill for this job

    +1 for not putting a membrane around the French drain if it is clay. If it were sandy better to have a membrane.
  6. thats true of normal EPS with a conductivity of 0.037 but graphite EPS is 0.030 compared with 0.024 for celotex. But I take the point.
  7. looking at comparable prices I can get graphite EPS 75mm @ £13.37 a board compared with celotex at around £34 a board. I think i know which one I will go with………...
  8. Terry, I like the idea of a small horizontal ceiling near the apex to allow a bit of ventilation under the ridge beam. I am looking at 60mm wood fibre board insulation as IWI to keep the wall build up breathable. Not the best thermally but less risk of interstital condensation and it has worked very well in our house. Hadn't heard of Diathonite but ill take a look Simon.
  9. not sure of exact type - look like this Ian
  10. i don't mind the idea of 75mm of solid insulation between rafter to allow a gap but I still don't quite see how that actually provides ventilation since at the moment it doesn't have anywhere to go at the ridge (though clearly has to be much better than no gap). If using celotex between and below the rafters and taping joints presumably I can do without a vcl/airtight layer but am losing a breathable build up. If using 75mm EPS between rafter, 75mm EPS below rafter and intello the u value not quite so good but more breathable.
  11. no counter battens, just horizontal battens straight onto the rafters. Not much sag either.
  12. I am converting an old barn into an office space and am considering the best option for insulating the pitched roof at rafter level. A new roof was put on it just before I bought it to ensure that it wouldn't fall foul of a planning timescales. So I am very reluctant to reroof but that makes it harder to work out a sensible insulation plan. There are no plans for cooking facilities or shower but there will be a toilet/basin. At the moment the structure is: new clay tiles (tight fitting) battens breather membrane (2 types, don't know what sort, but modern, not felt, so I presume is breathable) rafters (100mm) purlin (minimum 150mm, max 200mm) Rest of structure is 500mm thick stone walls where I will put on lime render/wood fibre board and a limecrete floor. For the pitched ceiling I was hoping to do something like this: tiles battens breather membrane rafters (100mm full filled with fibre glass) graphite eps (75mm) intello airtight/vapour control layer batten (25mm) plasterboard +skim (15mm) This leaves all the purlins exposed as I want and as much insulation as can be had but doesn't have any ventilation under the breather membrane. Except that the build up is breathable and there will be some ventilation through the tiles. Even if I try and reduce the rafter insulation so it is not fully filled air getting in at the eaves wouldn't have any where to ventilate without installing some sort of tile/ ridge vent. Even then there isn't any cross ventilation that you would have with counter battens. In an ideal world I would have the roof off, cover with 100mm eps, breather membrane, counter battens, battens, tiles. But that is going to be so much more work building up walls, planning issues, reproofing that I would really like to find a simpler solution. Any thoughts appreciated.
  13. jfb

    Thinking about buying a digger

    I'd go for a 3 tonne digger rather than smaller if you have land and lots of landscaping to do.
  14. if you have a bunch of cuts to do - fix a couple of bits of wood (parallel to pipe)to a surface that hold the 110mm pipe nicely on the surface (stop it rolling on surface). Much easier then to do cuts/chamfering.
  15. It sounds you are doing all the right things and I would not be surprised if you didn't get well below 3 ACH. I did a full renovation on my old stone farmhouse and got a result of 1ach. Like you at the beginning I was not sure whether to go for Mvhr or not but I am glad I did. I had the benefit of doing the whole renovation in one go so easier to deal with tricky ceiling/wall junctions, etc and the more I read up on it the more further lengths I went to. So go for it. Make sure you plan duct runs for the Mvhr as early as possible. I used twinwall flex duct to make it easier.