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SuperPav

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  1. Can anybody recommend an alternative 100mm (400mm width) slabs to Knauf omnifit that may be available in stock? I'm now getting estimates of 4-12 weeks for this which, in addition to being too long, is also entirely unreasonable as 4 and 12 weeks are very far apart! It's for full rafter fill room in roof at 200mm depth.
  2. Triple glazed makes sense if one or both of the following are true: 1) They are deeper frames (at least 40mm preferably) than the usual 24-28mm double glazed 2) You need additional noise protection There are 2G systems with a lower U-Value than some headline 3G offerings. I do think we're slowly getting to the point now though where by 2030, 3G will be expected by a big enough chunk of housebuyers that if you're replacing/buying windows now anyway and the uplift from 2G is <50%, it's probably a sensible investment almost regardless of the performance benefits.
  3. Appreciate this is a very trivial thing, but how would you tackle the following: We have (in a couple of places) fresh block inner leaf (aerated), which will be dot and dabbed 12mm plasterboard. Where the wall ends (corner), we need to continue in line with it with an internal partition stud wall, but such that the wall is continuous. Where would you put the sole plate of the timber? 1) Face aligned with the block work? In which case if you screw PB onto the timber, it would not sit flush with the D&D PB on the block wall. 2) Face aligned with the block work, but then put PB off cuts or other spacers once the adjacent wall is D&D to pack out the PB from the stud? 3) Or do I bring the timber stud wall out by a nominal e.g. 10mm and then try and get the D&D PB to line up with it?
  4. The window would not be structural by default. If you need it to be structural it needs specifying as such. Assume by solid brick wall you mean no cavity. Putting a window in where there isn't one already is slightly different than putting one in a replacement window (which has no lintel currently). The easiest way to deal with the inner leaf is to slide in a Catnic ANG section lintel (it's basically a piece of angle), the cheapest would be as you describe, to remove a course of bricks (while propping the course above with acrow props and needles or strongboys) and replace with a prestressed concrete lintel. The outer leaf is a bit trickier if there isn't a lintel or arch there, as you'd need an angle or inverted T section so that all you see is the flange.
  5. Yes I've seen that and that's what's annoying. The contractor was the "local" contractor appointed by BASF when I enquired for a Walltite quote. He did say that if it was hardened lime mortar (i.e. 2 years old) then he'd chance it. The worst part is that i'm sure if you do it slowly and carefully, it would be fine, but we've got to this "computer says no" situation. I might try to ask BASF technical department directly.
  6. So I've just had the surveyor/estimator from the foam insulation company out to site today, and they say they can't do full fill foam injection because the outer leaf is stone with lime mortar, and the foam will cause cracks/bulges. They're now recommending bonded EPS beads. This is *very* frustrating, as they never mentioned this previously, and the whole build detail was based on the fact the cavity would be foam injected. Two issues arise from this: 1) Airtightness - the blockwork, cavity to rafters closure, and joist penetrations all have relatively poor detailing, and the foam would've fixed all of that. However, I can at least remedy this by foaming all the joists gaps and top of cavity, and parging the blockwork. 2) Cavity trays - this is the bit that I'm struggling with. The house is a U shape, and the inside of the U has a flat roof. The cavity extends down below the level of the flat roof, and there are no trays fitted. Now we could pump the whole lot down to internal ceiling with EPS beads, but I worry that some moisture will find its way through, and we'll end up with wet patches on the plaster. Retrofitting cavity trays at the bottom of the stone leaf is so time/cost prohibitive at the moment that it's off the table. I asked the company if they could foam fill up to the level of the flat roof, and then EPS, and they said absolutely not as they can't mix the two materials due to warranties etc. So it's up to me to sort out the prep/detailing. I'm now thinking of using 1-part expanding foam to essentially create a full-fill cavity plug at the level of the flat roof, to act as a barrier to any moisture, with the EPS beads above it. It might not be as 100% impermeable as a cavity tray, but if any little moisture does end up in the cavity, it should stop it draining all the way to the bottom? We are not in an exposed location at all, and the inside of the U part of the building is even more sheltered. Any clever thoughts?
  7. Worth it for the information/detail/level of owrk you get out of it for your £500 or whatever fee? No. Worth it for the proactive engagement that it enables, for you to subsequently reference in your application and tweak the proposal with associated goodwill? Yes. Our pre-planning application was an utter joke and resulted in complaints and a refund as they were so useless. However, eventually I had a meeting with another planning officer and a conservation officer, both of who were very good, and went over a few options we'd laid out for the proposal. They expressed preference for some of the layout and details and materials in one or the other, and that basically meant that when we did the final submission, we did it in such a way that ticked all the boxes of what they wanted. This meant we had much less back and forth on contentious points throughout the actual planning application, and resulted in a straightforward approval. It does depend on the proposal though and how complex or contentious it is from a policy point of view. For small/easy schemes etc., it's cheaper and arguably easier to just whack in an application, and treat it as the "pre-application" if it gets rejected and you need to resubmit a freebie.
  8. I have to question why, but then again most things I do someone would quite reasonably question why If this is "just because I want to prove we can build this thing without concrete", then that's fair enough and crack on with it. However, if you want to reduce the carbon footprint etc. it's not as clear cut as just cutting out concrete completely. So if you want to proceed without concrete, just look at how houses were built 300 years ago, and repeat? Dig down strip trenches until you hit hard ground, then use bricks or (if you're made of money) large stone over a wide footing, build up to ground level with lime mortar, then have a suspended timber floor. This can be easily insulated from below, and you can overlay a UFH system in either boards, or if you want a bit of thermal inertia, you can simply fit the pipes between joists in a layer of sand. Alternatively if you're okay with lime, then do the same for the footings, but instead of suspended timber floor, whack down some glapor (or equivalent), membrane, then UFH in limecrete.
  9. I don't like the cavity closers as they're difficult to fix to. Also, in the past I've had just as much success of cutting and wedging a piece of 50mm Celotex between the leaves and foaming it to create a much more sealed cavity closer. You still can't fix to it so need to take the fixings back to the inner skin via straps. I've also found you need to use insulated plasterboard on the reveals, as it's more rigid (and you can only fix to the inner leaf really). Below is what we did on the current build (essentially built a plywood box BEHIND the outer leaf with a 10mm gap). Unfortunately this only works easily if you aren't tied to matching course heights between the outer and inner leaf (in our case the outer is cropped stone, inner is blockwork). Our cavity is fully foam filled, but I don't see why this sort of setup wouldn't work with other insulation.
  10. What am I missing here (something clearly)... For application in a pitched roof between rafters (200mm full fill) Knauf loft roll (from Wickes) works out to £4/sqm at 200mm Omnifit roll works out to someting like £11/sqm at 200mm Recycled PET at £15/sqm Sheeps wool at £35/sqm Now, I understand why the recycled PET and sheeps wool would be a lot more, but what is the difference between the "loft roll" and the frame/omni roll products? The thermal performance doesn't look massively different to warrant going from £4/sqm to £11-12/sqm? Or is it that the loft roll stuff isn't suitable for use between pitched rafters for whatever reason?
  11. An extract below a window would be really ineffective at doing what you want from it. What's the room and ceiling layout? There's usually a way to find a solution. The extract needs to be as high as possible, and ideally far away from the door (if not immediately above or adjacent to the shower).
  12. Never tipped a delivery driver, but probably should do something to recognise our local Amazon and Hermes drivers. For all the shit we read in the news, there's about 3-4 regulars, and over the years they've always gone out of their way to leave the packages, even when it involves them entering a building site, clambering over some rubble and putting it safely in a box somewhere. It's a thankless task, with ridiculous time pressure and having to drive through difficult towns and villages trying to find houses with no number or name.
  13. Seems like only when installed! Although this is tipping the balance now towards me just using my relatively inactive Ltd company to branch out into energy-saving material installation. If I VAT register through election (currently only turn over a little bit so below the threshold in planning consultancy/design), I can then install all of our insulation (~15k's worth) and even with me paying my Ltd company a nominal labour rate for the installation, if it's all zero rated, it will save a decent amount. Otherwise I'm either paying 20% on anything I DIY install (as it's a renovation not a new build), or I get 0% on installed materials but paying someone the labour will wipe out any savings. Although I am pleased that we were delayed in getting the cavity wall foam insulation - that should give a modest £400 saving by losing the 5%. All this of course assumes that the firms won't just up their prices by 5% to offset the VAT...
  14. Never worked with that, but I've found either a 14-15tpi plastic handsaw or a serrated knife the best for most types of insulation. The plastic saw is much more fine toothed than a wood saw and so catches much less. Don't know how much of an issue this is with the honeycomb stuff though. https://amzn.to/3igUBDr https://www.screwfix.com/p/bahco-15tpi-wood-toolbox-saw-14-355mm-/44210?tc=AL4&ds_kid=92700055262507126&ds_rl=1244066&gclid=CjwKCAjw_tWRBhAwEiwALxFPocvzzJ3MAdsY88RVriAsTbjBFGhYmHCliJla_RE1mj2IjSCc7YP-BBoCMJEQAvD_BwE&gclsrc=aw.ds
  15. I'm not sure I understand the section detail here of 2x133 beams under the 350mm wall. The indiviual leaves should really be centred over the web of each beam. Which would mean an akward 15mm protrusion of the chords either side of the wall. In any case, I'd fill the inside web (facing the room) with 60mm PIR, and then cover over the beam on the interior side with whatever thickness of insulated render board (marmox/wedi) that brings you flush with the plasterboard. Board the underside of the beams with the same insulated board, and then pump the cavity full of beads which will also fill the space between the two beams. Also I'm not a structural engineer but I've yet to be convinced that bolting two beams at 600mm centres achieves anything when used in a cavity wall installation. (We have independent beams in our build for the two leaves).
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