GraemeHM

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  1. @dnb @TonyTGreat info in this thread guys, thank you. One follow up question I need a bit of advice on…I plan on putting external lights at the same height as the internal ceiling safety zone. The cables would be run in that zone (batten service void), pass through the timber framed/rendered wall (260mm) and terminate directly into the light fitting Do I need to joint and change to swa before the cable passes through the wall or can I continue in t&e but put in a short length of metal/plastic conduit? Do I need to put a box and blanking plate on the inside wall surface to show presence of cables even though it’s in the safety zone? Cheers
  2. So if I understand correctly, you say that insulation on the outside of the walls? Originally I had wanted to insulate on the outside of the walls too i.e. on the outside of the OSB then the batten, render board etc. I was told by the render technical guy that this was problematic. Any thoughts? Should I recheck this info?
  3. @tonyshouse Thanks for that, I appreciate input. I have read a bit about condensation risk in timber frame at the sole plate, but hadn't followed up on it. So if I can use an aerated concrete block then this should reduce that risk, right.... so what about this... please stay with me.... Earlier @Mr Punterpointed out that I should have a 150mm upstand to ground level, so following his input and yours, I could use two blocks. The base on its side, the send on its edge. So that gives me an extra 100mm to get my upstand. If both blocks are aerated and I face the top block with PIR behind the sts construction board would that reduce my risk of cold bridging from the outside and hence condensation. I appreciate that the concrete slab could (possibly would) cold bridge from the underside through two aerated concrete blocks, but hasn't that got to reduce the risk? Please see attached...What do you think? Cheers On a side note my BC design guy has specified 7.3n blocks which for a single story extension is possibly a bit of overkill? Detailed structure x-section 31-3-21 two block +.tif
  4. @tonyshouse Thanks for the input. Thermal bridging I understand, but what analysis of thermals are you suggesting so I can find out more. Others have suggested Marmox but it's hellish expensive are there any alternatives that I should look at?
  5. @Mr Punter Do you think the attached would cut the mustard. Following your suggestion I have increase the difference between outside and inside and dropped the render carrier board down. Also added detail about perforated pipe and French drain. I am trying (I suppose) to keep to a single block on the perimeter. Many thanks Detailed structure x-section 31-3-21 2nd.tif
  6. @Mr Punter Thanks. I did think about marmox as it came up on another post, but I looked at the cost and whilst I’ve tried to do a good job on the insulation we are tight on budget. So on the DPC is that 150mm up from the outside ground level and under the sole plate? How important is that?
  7. I hope the attached drawing makes some kind of sense. We are just about to start digging down for our extension. There is fairly straight forward trench foundation and concrete pad. We are planning doing a single pour for both trench and pad. Then a single course ring of 140mm wide blocks (excluding the doors) to build off. 150mm (400mm c/c) stud work filled with Rockwool with the wall and floor build-up shown. My question is about the DPM and upstand on the outside. There isn't much detail on our architect BC drawings and want to check with the collective knowledge on how good (or otherwise) you think this construction is. Thank you! Detailed structure x-section 31-3-21.tif
  8. Thank you @Thorfun & @craig for your help, it’s such a subjective decision. Be bold or not 😳
  9. @ThorfunWe are wrestling with the same decision right now. Originally we were going anthracite outside and inside but we've had a bit of a wobble just as we're about to confirm the order details. Can I ask, do you really notice the inside colour or has it blended in? How easy has it been to match in other interior colours? What colour paint have you gone for on the walls and reveals? Excuse the cheek but could you DM a discrete picture or two?
  10. @Tom's BarnHi Tom, Thanks for the feedback. I spoke to one of the sales managers who couldn't be more helpful. I was planning on using zinc, but the cost of this product makes it much more attractive. The guy we are using said he thought it was an excellent product, but great to have a customers view. BTW I didn't get your personal note.
  11. @Dunny1234I should say that are also considering using an aluminium roof PREFA / Preflaz and it seems to have a good reputation.
  12. @Dunny1234Yes the condensation is a big concern and as @Russell griffiths says all that insulation on top of our rafters makes our roof angle more problematic. Our architect also preferred warm, but soon changed his mind 😂 I've read things about there being more noise on a cold roof, but not sure about that. I've also read that a vented roof keeps heat (we are south facing) away from the roof structure. Other considerations (as I understand) if you have rooflights, care must be taken to keep the ventilation open and if you are joining another building like us, then the abutment is slightly more complicated.
  13. @Dunny1234We are just about to start building as well and I've been doing research on cold/vented vs warm/unvented. Our zinc installer has always favoured cold/vented. I spoke to a very knowledgeable technical guy at VM Zinc and he said "both will work if done right, but the cold/vented is more forgiving". As you probably know the issue is condensation on the underside of the roof.
  14. @Russell griffiths No not Comax product. I should have said. I have been recommended an aluminium product by PREFA an Austrian company ... Roof system Prefalz® | PREFA comes out at 0.7mm thickness. I have been looking at VM ZincPlus again 07-0.8mm thickness. They all seem incredibly thin, that said the small samples from VM zinc I have do seem quite stiff. I have been vexing about this (as you probably have seen) for quite a little while. I have researched and talked to a few people. The self installed products are tempting, but I've been told that the click systems aren't as good as a properly crimped seam from a pro installer. Especially important at 6 degree pitch, plus we've got a couple of rooflights to get around and I'm just not sure I would do a good enough job.
  15. @Tom's Barn Hi Tom, Looks AMAZING! We have been recommended to use PREFA aluminium for our single story low pitch (6 degree) roof. May I ask how, are you happy with the PREFA product, the quality and how its stood up to the winter? Any thoughts much appreciated. Graeme