MortarThePoint

Any other options? The render is booked in for just over a week's time. He'll need the scaffold to stand on too

Why will it leak? Won't any water striking the flashing drain onto the soakers that are tucked under it.

I'm specifying the windows for our bay window and it's raising a lot of questions that I'm sure the wiser among us have come across before. Below is an extract from the elevations drawings and a dimensions drawing of what the masonry and window elements look like in the bay. Questions: Window tolerances: Across the front to the rectangular bay the dimensions are in the hands of the window manufacturer as it's not like it needs to fit with a reveal that is slightly off nominal or slightly off plumb. So there I presume I specify the actual dimension I get by measuring on site and subtracting twice the desired amount the windows are to be set back from brickwork (twice because one set back at each end of the run). That leaves the dimension between the pillar and the brickwork wall. Here we are subject to variations in plumb etc. For my windows in reveals I have allowed a tolerance of 5mm to the cavity closer and lintel on all four sides. Do I just allow a tolerance of 5mm on these side dimensions? If so that yields left: 695mm - 2.5mm(cavity closer) - 5mm(tolerance) = 687mm and right: 705mm - 2.5mm(cavity closer) - 5mm(tolerance) = 697mm. Is that correct or am I missing something or being too tight with the tolerances? Roof support vs pillars: I'm pretty sure all the windows quotes I have had have said their pillars aren't structural, so I need to work out how best to support the hipped bay roof. Making it self supporting off the wall could be a big ask as it will put a lateral force on the wall that will try to pull out any fixing used at the roof's pitch abutment*. The rightangle bay posts in the window range I have gone with appears to include a metal corner post and jack arrangement, but no information about how much weight is allowed. The roof is around 1100mm x 4200mm at a 45 degree pitch (1.5m pitch abutment length) so that works out as 1.1m*((1.5+4.2m)/2 + 2*(0.5*1.1m))*1.41 * 77kg/m2 = 572kg is just tiles. The load is mostly on the wall side, but I can easily see >100kg required on each pillar support and that's before adding any snow load etc. I guess a factored load would be more like 300kg. [*] Force calc: taking moments about the bottom left corner and just considering tile weight: F_fix*600mm = 77kg/m2*(1100mm*600mm*1.41) * (1100mm/2) --> F_fix = 66kgf = 0.7kN (first 600mm is the vertical distance to the fixing from bottom of 'truss', second 600mm is fixing spacing). There are other weights to be considered so probably more like F_fix = 2kN, perhaps 1kN if using one fixing every 300mm instead. Most of the blockwork is a low panel beneath the window so no real weight to the wall there. Abutment lead vs render: The render above the bay roof needs to go on before the roof is in place (scaffolding in the way). This means what would normally be supporting the lead isn't there yet. I think I understand the approach here. The roofer puts in flashing flat to the wall which gets mostly rendered over. The roofers then tuck their soakers under this flashing when the roof gets installed. Above the windows: There is a short vertical distance ~450mm that needs to get framed out in timber. This is then to receive 12mm painted plywood. Across the top of the windows 2no. 50x200mm timbers. No real need for soffit, but will need sprocket, fascia and guttering.

OK for now. My local Minster and Travis Perkins have the standard stuff in stock. The BG Acoustic and deep track needs ordering in (e.g. from CCF), but that's only a couple of days (supposedly). Prices have been going up, but nowhere near timber.

No test thankfully and likely overkill anyway ?

Does anyone know if I should start a BG acoustic stud (Acoustud) partition on a blockwork abutment with a standard C-stud or on a vertically mounted section of floor/ceiling channel? The BG Acoustud doesn't have a flat back so won't work screwed t a blockowork wall. Tried getting an answer from BG but their swamped and haven't responded.

Hmm, looks like TradeLine specify 400mm centres though! Also with reduced GL2 c/c. https://user-ehptxzr.cld.bz/ccf-bookshelf/Tradeline-Brochure-2017/86/ GL1: TradeLine 2.5m/m2 £0.83/m, £2.08/m2 GL2: A Hough 12.5p each but 4.2/m2 GL3: A Hough 18p each but 0.7/m2 GL8: TradeLine 75p/m That makes the arbitrary 4m x 4m room 16m2*(£2.08/m2 + £0.53/m2 + £0.13/m2) + 16m*(£0.75/m) = £55.84 or about £3.50/m2 plus screws which is more than BG. BG is only at 600mm centres with GypLyner if using 15mm plasterboard though: WhiteBook C06. S04. P07 If using 12.5mm plasterboard the TradeLine offering will still be cheaper than BG despite using more GL2 brackets.

I've had some prices on TradeLine and it is much cheaper: GL1: TradeLine 1.67m/m2 £0.83/m, £1.38/m2 GL2: A Hough 12.5p each which is similar to Builder Depot GL3: A Hough 18p each which isn't better than Builder Depot GL8: TradeLine 75p/m That makes the arbitrary 4m x 4m room 16m2*(£1.38/m2 + £0.18/m2 + £0.09/m2) + 16m*(£0.75/m) = £38.40 or about £2.40/m2 plus screws.

That works out as £6.50/m of wall uplift to timber plus resilient channel at around £6/m of wall.

With a timber wall, you're looking at starting around STC32 and going into the 40s at best without using resilient bar (aka resilient channel) or doubling up on timbers. Timber highlights from IR761: Page 26: 406 c/c, 90mm timber studs, double layers of 13mm plasterboard, mid density insulation STC 38 Page 178: 610 c/c, 90mm timber studs, 16mm plasterboard, lower density insulation, resilient bar one side 406c/c STC 50 Page 218: 406c/c, 90mm timber studs, double layers of 13mm plasterboard, lower density insulation, resilient bar one side 610c/c STC 57 Page 350: Double timber wall, 610c/c, double layers of 16mm plasterboard, lower density insulation STC 69. Good below 125Hz (e.g. 26.7 @ 50Hz) Some MF highlights (copied from previous post): Page 89: 610 c/c, 90 steel studs, 16mm plasterboard lower density insulation STC 50. Page 93: 610 c/c, 65 steel studs, 13mm plasterboard (double on one side) lower density insulation STC 51. Page 120: 610 c/c, 90 steel studs, 16mm plasterboard (+13mm on one side) lower density insulation STC 55. Page 124: 610 c/c, 65 steel studs. two layers of 13mm plasterboard each side, lower density insulation STC 55. Page 245: 406 c/c, 90 steel studs, two layers of 13mm plasterboard each side, low/medium density insulation, resilient bar one side 610c/c STC 60. Page 350: Double timber wall, 610c/c, double layers of 16mm plasterboard, lower density insulation STC 69. Good below 125Hz (e.g. 26.7 @ 50Hz) So looks like you get about the same result using 90mm timber studs with single sided Resilient Channel as you do using 65mm metal studs. Mapping to the UK that would be 95mm timber and 70mm MF. The timber option is about 40mm thicker and currently more expensive. 70mm MF is around £1/m of material whereas 4x2 is above £2/m of material and would need the resilient bar on top of that.

Internal. I have two kids and like the sound of mechanical clocks and a good read ?

My comment was made a bit quickly. Pointless to go nuts with the soundproofing if the door isn't specifically sound proof. Even then, the door is likely to be the weak spot in any wall above 44dB which is a single skin each side (denser board type) insulated wall of C-studs.

Important to remember that any wall with a door in is pointless to soundproof ? link

I've been getting my head around Partition duty and I think I'll be happy as long as it is Severe duty in certain places. BG Habito is expensive (£20) and only available to me in Pallet quantities (38 @ 2.7m). It's good stuff though and the BG System Selector says a sheet of Habito either side of a 70 S 50 C-Stud is Severe duty rating with Sound Insulation of 38dB. That's with no insulation and they don't give a value with insulation. However, I can deduce from page C04.S02.P04 of the White Book that adding 25mm of acoustic insulation adds 6dB, so would make that combination 44dB. Given the incremental cost, I think I'll go with the Acoustud and SoundBloc upgrades which give Severe duty and 58dB sound insulation, the same as insulation + 2x SoundBloc each side. That gives me some combinations that all have 58dB: Habito + Soundbloc both sides £65/lm Habito + SoundBloc one side, 2x SoundBloc the other side £57/lm 2x SoundBloc both sides £49/lm In less sound and duty sensitive locations, I can go single skin with 50dB: Habito both sides £47/lm Habito one side, SoundBloc the other side £39/lm SoundBloc both sides £31/lm Future proofing with Habito is going to cost me a fair bit, but not as much as if I was to put Plywood or OSB in at their current prices. I may end up with some Habito sheets left over though. I can do this as I don't have many metres of partition to address. For reference, a 40dB 70 S 50 wall (with insulation) would be around about £18/lm I think. On this, SoundBloc each side adds about £8/lm and the Acoustud adds about £5/lm. I don't have any fire requirements above 30 minutes.

The MF looks great. I've never seen it in the flesh so it's great to see. I see they have included the deflection heads by using the deeper track which is good. Crazy how much more expensive the deeper track is than the standard track. (about 3x).

Cool, thanks. Looks tidy and good large service openings in the studs. The Tradeline studs look to have pretty small service openings. Are they standard 92mm C-studs? Hammer in similar to these: https://www.builderdepot.co.uk/spit-udz-6mm-x-35mm-fire-resistant-hammer-in-fixing-pack-of-100

@Conor to understand your install a bit more I was hoping you don't mind me asking the following Do you know what fixing they have used to attach the GL2 brackets to the underside of HCF? If not, a close up photo would be cool. Did they put up the MF for partitions first? They haven't used GL8 perimeter along the ICF which I guess is to do with the ICF. Do you know their plan at the edges? What plasterboard are you going to use under this? Thanks

Architect has included enough details. He's specified 150mm void with Casoline MF. I don't want or need such a large void.

I'm tempted to go for MF I-studs rather than C-studs but they are about 3x the price without supported pricing. In terms of feeling solid, Does anyone know how 70mm I-stud compare to 92mm C-stud? Having a 6y.o. who already likes slamming doors doesn't bode well for the years to come if I don't have solid feeling partitions.

This one includes Resilient Channel

Sorry you did say that. Found an installation video. The brackets look to be GL2 and the channel is GL1 (sections can be joined by GL3) and a perimeter of GL8 (also used for pattresses). GL1 brackets seem to normally go in at 600mm x 1200mm centres. GL3 joins sections of GL1 as required. In parts (Speed Pro not BG): GL1: 1.67m/m2, £1.14/m, £1.90/m2 https://www.builderdepot.co.uk/metal-lining-channel-3600mm-gl1 GL2: 1.4/m2, 12p each, 16p/m2 https://www.builderdepot.co.uk/195mm-gypframe-gypliner-brackets-gl2-box-of-100 GL3: 0.3/m, 0.5/m2, 12p each, 6p/m2 https://www.builderdepot.co.uk/gypframe-gypliner-channel-connectors-gl3-box-of-50 GL8: £0.83/m https://www.builderdepot.co.uk/metal-track-3000mm-gl8 An arbitrary 4m*4m room would cost 16m2*(£1.90/m2 + £0.16/m2 + £0.06/m2) + 16m*(£0.83/m) = £47.2 or about £3/m2 plus screws. BG may be more expensive as likely a better brand (?). 47x50 timber at 600mm c/c would be £2.75/m2 so GypLyner does compare well with the timber cost. Perhaps not so favourably historically, but based on where timber prices are now... Whilst the timber feels easier to install to a flat level surface, under the hollow core camber the ease of adjusting the metal frame looks very attractive.

Sounds neat, easier than chasing blockwork!

Looks great, what system is that? Do you have a link to the brackets?

Architect included a 150mm MF void, but seems pointless (no ducting). MF needs at least 100mm I think. To get it flat I was planning to pack each mounting as @Mr Punter suggests. To mount the timber to the underside of the HCF I was planning on something like these masonry screws at 400mm c/c.

Basic architect 'construction drawings'