PeterW

Where is your water source ..?? These work well on boats as there is a permanent water source available. Without a continual changing water supply you will not have the cooling available.

Just done one with Warmstar mat, cheap thermostat but the control is by a contactor driven by a decent programmable time clock that is part of a pair - one doing ASHP UFH and DHW, the other does E7 boosting of DHW tank and UFH mats and electric towel rails in the bathrooms. Not difficult to do and puts all in the same place for control purposes.

Seriously ..? You would switch off in the summer as it is providing your extract ventilation for wet rooms ..?

I’d prefer those who understand how MVHR works, nothing purist about this ..! The answer is yes, the SFP and flow rates of an extractor hood is significantly larger than a full house MVHR system. Ergo it will unbalance things and you have the chance of pulling warm moist air from bathrooms into your kitchen as the hob extractor reduces the pressure in the kitchen to the detriment of the MVHR system. Basic fluid dynamics and flow/pressure calculations, not rocket science.

This isn’t a recognised design detail in England & Wales so your BCO needs to sign off Why is the Architect telling you who to use ..? Make your own choices as you’re paying the bills. Approved by whom..?? Approved BRegs drawings are those approved by Building Control so unless they are “approved” then they aren’t ... So the builder will include the potential loss from not making any savings and then increase the price accordingly. You’re not making any money on this - you’re just reducing your cost as you’re not developing for profit.

Ok but you’re not defining a sarking board then. You’re defining an underlay of OSB. What has the architect drawn and specified .?? He can’t “advise” then wander off ..!! Who’s doing the Building Regs section drawings ..?? I would get myself into that relationship before you end up with “BCO says ....” conversations that cost you £££££. Also, I would never price a job on unapproved drawings or spec - who is adjudicating when BRegs comes back with X and your builder says he priced Y..?? Private BCO or Local Authority..?

Sarking south of Carlisle is unheard of ..! Have you engaged with BCO yet..?

2-4mm max depending on the fabric or rovings that are used.

Slate in a moderate to severe area has a minimum pitch of 22.5 degrees so check with your BCO that they will accept it. siga have tested to lower than that but it’s very specific on the design. Slate hooks, 150mm headlap etc

650 sqm @£2000/m you will be at £1.3m.. That basement is a very complex shape - could do some value engineering on it and get the price down as there are lots of detail corners etc that will add to cost and complexity.

Most cylinder sizing is done using 60 litres per day per person, tank at 65°C with a 21kW boiler giving a recovery time of around 45 minutes. It’s the old “rule of thumb” same as rad sizing and so on. None of that is achievable and suitable for ASHP as you tend to run cooler, heat source isn’t as powerful and modern houses use more hot water than people realise. If you size about 35% larger than this, you end up at nearer 85 litres per day stored so 255 litres rounds up to the next largest tank. You still need all the G3 kit including your tundish and PRV drains etc.

No it’s not ... minimum 250 litre for 3 people. 180 litres for 2 people. Secondary cylinder in the loft ..? How ..?? Thermosyphon and other issues, long lengths of pipework, recirc nightmare ... why would you ..? Ignore the salesman, buy a bigger and better tank (Telford HP 400 litre is cheaper than that unit you’ve quoted btw...) and do it properly. Bring it forward ...??? Ful height unit wouldn’t notice.

About 1.5 times the thickness as it’s UValue is around 0.032 to 0.037 and PIR is 0.020 to 0.023 So 300mm of frametherm is good, but at that point consider Warmcell blown cellulose as that is even better.

Which way up you putting the tee ..??? And where ..??

Issue is if the first bend blocks then you have the volume / weight of the stack full of ... well, you know what, pushing back up hence the 45° I’ve put in. Plus, this is basement so we have double stack above and BCO will normally insist on long rest bend (well will round here..!) as otherwise you end up with a slow moving poo pile at the bottom of the branch..

Zone valve on the inlet side then is what you need (and would be good practice anyway)

That’s a very small but very expensive tank then ..! Still appears to have rear connections too. I’d be putting a standard kitchen unit in there and leaving it, tanks don’t belong in the kitchen.

You would put a 45° Y fitting on the current connection then the rest bend at the bottom of the stack into the straight inline, then connect the WC to the branch. TBH I don’t like the two changes of direction - before you concrete this lot in I would get Buillding Control to give it the thumbs up.

Isn’t the Veissman the split unit ..? Or the weird internal boiler thing..? If so, find a plant room for it not your kitchen as they can make some noise. Also if you’re going split unit and it’s refrigeration then you need good access to run the lines and they need proper insulation. Also looking at the MIs for the unit all the connections are on the rear so you need access either side to install and service it.

@JulianB are you expecting to run the ASHP in cooling mode also..? Not clear from your description / diagram..?

Not an issue with distance to the manifold - just insulate the pipes properly.

Yes - you basically can write to say that “XYZ Engineer / Building Control state the foundations are no deeper than xM and using the 45 degree rule you are not required to serve a party wall agreement”

They do - it’s called the Tariff Information Label The problem is the rate you pay is based on your region and your MPAN identifier (first two numbers, mine is 11) alters the standing charges and the generator premiums depending on the fees available.

Same thickness as a frame so about 110mm.

so this is bridging between two internal spaces - of you line them with PIR and they fill with ice or snow they don’t create cold points and potential condensation issues internally. It doesn’t cost much but can make it much better than just a flat timber gutter that can be a nightmare to insulate from the inside due to rafter ends etc.