SBMS

Probably LVT. I would imagine a bit of 9mm ply on top of the LVT then 3mm screed over the top and then the LVT?

So in practice you think just fill to the purple line and it'd be okay? I guess it's below the DPC? Any issues with thermal bridging as @Dave Jones seems to indicate a marmox block would be useful?

Does the extra expense justify it? Is there much thermal bridging going on?

Following on from my previous thread... Architect has designed this as a flush threshold detail to help minimise thermal bridging across our triple track sliders, but also provide the 'solid' base that the door manufacturers insist on (they had a wobble regarding having any PIR under it due to them being sliding and heavy). What are thoughts on this as a detail? Not sure how the slab gets poured leaving the haunching in the concrete infill in the cavity - would it matter if it was continuous?

It’s the downstairs one - circled in red on the attached with walls shown:

Thanks everyone

Thanks @joe90 that’d be great. It sounds like there’s options. I can ask our SE and was going to go to Stairbox but maybe a bespoke set are needed

Thanks @nod but that’s what we are trying to avoid

We’ve got a half turn/switchback staircase. I’ve now just realised that we’ve got try and work out how to support the half landing. Timber or oak staircase so no modern steel thing that could be self supporting. Fairly stupidly I now realise, we had assumed that the half landing would be floating - as the staircase is in a corner. But there’s nothing to support it at the fourth corner (layout attached below). We could probably support the fourth corner marked with an X below via a post, or box the stairs in, but would really rather not. Is it possible to build some sort of a steel frame that cantilevers and supports the fourth corner so it floats? Can the half landing be supported by the staircase rising up to it (always read that staircases hang off the floor so need the floor to bear the weight of them, not other way round). I’m no engineer and will probably ask our SE but wondered if anyone had come across anything similar?

What is your planning consultants view? My counsel would not be to focus on what’s existing, reduction in space, existing pool etc. Whilst logical in our minds, they don’t form part of the planning policy around permitted development rights, and I don’t think would be considered on appeal. I think in a full plans application, an inspector might give weight to these facts as there is policy around existing development but I don’t think there would be for PD. I would suggest to others to keep your appeal (if you’re writing it yourself) to the absolute facts and policy on the ground - and that’s the issue of ‘incidental to the dwelling house’. Which I would think is clearly demonstrable in your case. Don’t give the inspector any opportunities to respond negatively to your appeal by including things that don’t serve your application. Be interested to know if the above is consistent with your consultant’s view, or if they think your existing site makeup is material to the appeal?

Yes - I think that one is a bit darker. Struggling to find one that matches that lightness, most reds are quite a bit darker

Anyone know what a good match to this brick is? I think it’s a light red multi? this is another similar one (less busy) - any ideas?

ChatGPT and other generative AIs (don’t get me started on the terrible misuse of the term) are simply stochastic language parrots, and unable to perform any actual maths calculations. So wouldn’t trust them to actually deduce anything!

Yes, it was more about the cycling that JohnMo mentioned that I was trying to understand.

For those of us not in the know, and who are setting out on UFH design with an ASHP can you summarise the point regarding centres and flow temp?

20%?? I’d be tempted to put it in the cavity if this was true.

Not that much of an impact. The engineer at Pasquill has over specified it and a 202mm joist will suffice. I think he specified it for a traditional soil + greens roof makeup whereas we are using a lighter tray system.

If you could reduce your joist depth to 202mm - 2 layers of super quilt plus 40mm PIR making 242mm yields 0.15 u value. All warm roof. We’ve got a 202mm posi joist with green roof loading… alternatively if it’s the Mbc detail then it’ll be a 300mm joist (0.14 u value with cellulose) which you could do with a 202mm with 1 layer super quilt and 80mm PIR.

With difficulty. It's possible but once I started looking into it, I realised that the detailing had to be exact and a warm roof was much easier. The detail you've posted looks like MBC's flat roof with cellulose. Are you sure the joists are 254mm and not 300? 254mm cellulose filled wouldn't be a great U Value.. probably 0.16 or something?

Is it the MBC flat roof detail (300mm joists achieving 0.14)?

What’s your current joist depth your cold roof is working to - or to put it another way, what’s your maximum height you’ve got for the warm roof make up and the u value you’re trying to achieve?

We’ve had this exact issue with our flat roof design. We are going with 304mm posi rafters with warmcell for our pitched roof. Originally we were going to do the same with the flat roof portion but then another BH member pointed out the need to ventilate this. Then came the issue that cross ventilation with a parapet wall around the top is incredibly difficult to detail successfully. I decided to switch to a much simpler warm roof design with PIR on top. Any reason you’re not going warm roof for the flat roof? Much easier to detail.

@Mr Punter in both details or just in detail 2? Is the second matrix block required in detail 1?

Is the thermal break just required across the cavity to outside brick junction (irrespective of the depth of the track), or should it extend past the inside edge of the track? My example scenario shown below with a 186mm deep track: Detail A looks much easier to construct?

Marmox block = 65mm width. Track depth = 186mm. So where under the track is the marmox block positioned?