Iceverge

Ah I didn't realise you were underway. The plan looks fine in that case. I was thinking you were still at the design stage.

Would you care to add some plans too please?

I calculated this. From memory all you need to do is widen the cavity by about 5mm to make up the difference. SS every time. Here's my alternate version of the above detail. 1. Full fill of EPS beads, right to the foundation. Allowance for mortar droppings so they won't build up to DPM level. 2. Less thermal blocks, they don't really make a difference to the heat loss below the insulation in the floor. 3. 2 x Layers of EPS 150mm insulation with the DPM in between for protection. 4. Separate DPC on outer leaf. 5. 50mm insulation at perimeter really helps the heat loss. 6. Much easier to level this concrete floor than the other design. 7. Allows for the use of cavity ties below the DPC increasing stability. 8. Simpler threshold detail for DPM.

If counter-battening would make the floor too high I have another suggestion. Buy some 3.6mm plywood and rip it into say 300x50mm sections. Use a laser level or string line and tack or staple the ply in place to get it close enough to level. When the floor is finished use some self levelling compound to take any last imperfections out if needed.

Have a look at the kg/m3 figures. The denser the better IMO. Also I prefer slabs to rolls in general. What joist spacing do you have?

It really helps. A tip from our Welch wizard. @Nickfromwales

A great stage to start this thinking rather that 6 months down the line. Keep an eye on this. Shrink the house to fit your budget with sone contingency. There will come a day when you need to throw money at it to overcome some obstacle. Passivhaus is designed to be an economic corner where the added efficiency gets rid of the need for a conventional central heating system. If it's costing £50k for £500 then you've done it wrong. Use the spreadsheets here to get a feeling for the balance of heating needs. Forget GSHP and battery's. Too dear Vs the benefit. Don't bother with the PIR internally. Just widen the cavity. Stainless steel ties are cheap enough. Use separate lintels for both leafs. 200mm cavities are the norm where I live. North facing glass is bad for energy efficiency. Careful with this. Airtighness is the lowest hanging fruit. It's a very big house, sub 1ACH should be very achievable.

That's a shame. I was interested to see how much of a difference they would make to the sound.

You must have very good windows. What profile did you use?

Can you not just tape the sips to each other internally for airtighess? What are you planning for your final rain screen? A block external leaf or cladding hung from the SIPs?

Or use EPS beads.

Have you this fitted yet? If you were to put it exposed on the ground floor ceiling it would really help quieten the echo in those rooms. The way I think about airborne noise is to compare it to water sprayed from a hose. Obviously if you were to get lots of splashback like you would from plain plasterboard then the same will happen with noise. Spray a hose onto wood wool and it'll kinda fizzle out. For sound it'll make the room much less "echo"y. The water hose though idea works for air gaps and reverberation too.

I really think UFH isn't the optimum solution here. 1. Too much heat loss downwards. 2. Too high a heat loss property requires quick warm up times. This means high flow temps means bad COP or poor boiler efficiency. 3. Disruptive to install.

You need to deal with 1. Airpaths - lots of acoustic mastic at any joints and at the walls. Seal all gaps. 2. Reverberation - A layer of fluffy stuff just to stop the drum effect.Thats why 175mm won't make much difference Vs 100mm here. 3. Impact noises - decouple the surfaces. You've done this with the resilient bars and to some extent the cork. 4. Add Mass. Plasterboard, standard or soundbloc or OSB is the cheapest way, more the merrier. (Insulation is a dear way to add mass)

€514/M2 plus vat in 2019 for a 2 story completely rectangular house without no big windows and a hipped roof. This was the twin wall frame and raft. Probably completely meaningless 5 years later however.

I'd be tempted to keep the gas boiler and install a few slimline vertical rads. Or if you really want an ASHP just get a good A2A unit like this.

The MBC package is the most complete one I know of. It's really well though out. The only bits I'm a little iffy about is the sparse window and threshold details.

The Harlequin I liked because it was square, plastic (no corrosion) and had all the connections on top. However 210l was far too small in my opinion without a gas or oil boiler on call. Also it couldn't be plumbed to a solid fuel loop. I can see the attraction of a PHE type too. What about one of the Gledhill Torrent Heat banks and an ASHP. It might work as an off the shelf solution. Of course the obvious answer of course is an UVC but the G3 servicing can add up over time.

Nice, what size did you go for? What would you estimate the temperature of the TS when it can no longer provide DHW ?

@dpmiller Did you install the Harlequin Heatstream in the end? I really liked the idea but thought the storage volume too small. If they could make an really big one it would be ideal for an ASHP.

It can be done safely IF you are fastidious with airtighness. Almost nobody is, hence the fear of hybrid roofs. You only get issues when you have more moisture getting in Vs getting out. Airpaths through the structure are the real risk when drafts carry moist internal air into the structure to below the dew point and it condenses. I have never ever heard of a structure failing purely through diffusion (vapour passage through materials) so it doesn't matter where the airtighness layer goes IF it is comprehensive.

Interesting topic this one. I laboured over the best DHW solution for ages. Ended up at a direct 300l UVC, mostly because I was sick of all the sales nonsense and high capital outlay. It works fine and doesn't cost too much to heat. Hopefully very little whenever I put in some PV. On my plumbing research travels I became quite attached to the idea of Thermal stores. I subsequent installed a 250l maxipod thermal store in my parents house to merge an oil boiler and a solid fuel Rayburn to deliver pressurised hot water. It works really excellently. Instant hot water, no G3 or discharge pipework to worry about. However It needs to be kept at a high temperature to deliver any reasonable amount of DHW. Not ideal for an ASHP. You could just get a massive coil in tank TS (say 600l) and it'd work fine I bet.

How thick are the rafters and I'll push something cheap and buildable though ubakus. Or you can do it yourself. https://www.ubakus.de/en/u-wert-rechner/? Also what's the planned build up above the woodfiber? This is extra important to know if you plan on a material of very low vapour permeability such as foil faced PIR. I'm not a fan or PIR between timber rafters. It's slow and wasteful to fit properly. Expands and contexts differentially to timber so is a recipe for gaps long term. It's poor for noise and fire Vs minerals wool.

Welcome welcome. De-identified Pics and plans always welcome.

I'm thinking we may have wires crossed! I would advocate burying any cash into the bits of the house that can't be changed or added easily later. Specifically MVHR Airtighness Insulation Triple Glazing.