WisteriaMews

I've just completed the survey. Any follow up questions let me know!

Build cost - I don't think £3,500 per sqm is that crazy in the south east if you are going to do a decent specification (e.g. you mention a lot of renewable tech). Build costs have gone up a lot post pandemic. I actually think it's refreshing they've given you an estimate (many architects don't in my experience). I'd suggest an open conversation with them on why they think that will be the cost They'll know the cost of their recently completed projects. I expect they have some comparable projects to yours that have cost £3,500 per sqm and that's why their suggesting that price to you. Architect fees - in my (limited) experience all architects base their fees on a % of your project cost. Stage 0-3 they usually price on a % what you say your budget is. When it has become clearer what the real cost is going to be they'll re-baseline for the later stages. There will be a lot of work in a 441 sqm building. It's really tough. It's a lot of money. It feels very frustrating when you get fee hikes / estimates higher than you expected / hoped. I'm sure you can cut the build cost. Do you have time to fight for every bargain and do work yourself, or do you want to give the job to a good main contractor and take pressure off yourself? In my experience a good architect is really valuable on a project. They'll come up with good solutions, they'll design nice spaces to live in, they'll take a lot of work off you, they'll solve a lot of problems. (I suspect my view are contrary to a lot of people on this forum.)

If they've just asked for a warranty quote, rather than a proof of policy, hopefully you can just give them a quote. Similarly can you just give them a solicitors details, but tell the solicitor not to do any work until you give them the green light.

*penultimate bullet point should say "buy the new build warranty before you commence work...."

It would probably be best to speak to a self build mortgage broker as they'll be able to offer some advice on your circumstances (e.g. Buildstore - not recommending them, but they are one of the bigger players in the market). The Buildstore website has into on it how the process works too. Generically I'd say: - I'd hope you can get an in principle mortgage offer without having to pay any fees. - Knowing that the mortgage looks 'do able' depending on your approach to risk you could then get a QS / costing to price your build, to know if the house you want is achievable within the amount you can borrow. - if happy, press go on the mortgage. Conveyancing, mortgage fees, stamp duty etc.... all kick. The mortgage doesn't cover these. - Once you have the land, you need a bunch of professional services; architect, structural engineer, soil survey, discharging planning conditions, building control, etc... Your circumstances will determine how many of these you'll need (you can never avoid them all). I've not seen a self build mortgage that will release funds to cover these fees. - In my experience you need to buy the new build before you commence work (as they send an inspector as you go along). - Unfortunately there are lots of outgoings before you start building!

Currently planning for our next self build. We are doing to have an electric heated towel radiator in all the bathrooms and I'm looking for a controller to meet our two requirements: 1. Ability to set a schedule via WiFi / an app. 2. A physical boost button that we can press to turn the radiator on for an hour / two hours. For the times when you have a shower outside of the scheduled times and want to turn the radiator on to dry the towels by just pressing with a button and not needing to faff with a phone / tablet. Can anyone recommend a controller like this?

@TerryE thank you for the detailed reply. I'm not as IT savvy so the above is probably a bit advanced for me! 🙂 Might be a silly question, but how.did you install the top and bottom thermometers? I'm assuming they are on the outside of the tank? Did you try to get round the insulation to install them on the metal skin of the tank? It sounds like you only use a top temperature sensor to drive the boost if needed? Being able to have a boost is my main concern, so I might be able to do something simpler than your setup. (I'm planning to be on Go / Flux rather than Agile so will have a set block of off peak that I can just use a timer for.)

@TerryE @JanetE I'm looking to specify the same tank in my new passive self build, but have been struggling to find out many specifics about the controls. Ideally I think I'd like to: 1. Heat to full overnight on off peak electricity - it sounds like it has timers so this should be possible. 2. If the tank falls below a certain level boost it so there is enough hot water for evening showers / so we don't run out etc... - I haven't been able to find anything on a 'smart' feature like this being possible. Are you able to share your experience with the tank controls. Thanks.

PHPP tells us it's sufficient. Still feels like a bit of a leap of faith installing such a low power system.

Yes, our architects are Passive House qualified.

We're planning a certified passive house and are looking to install a Zhender ComfoAir Q450 with the Zhender Comfoclime bolt on that does heating and cooling. Assuming we hit the passive house standard, that should be sufficient for us. I see you mention above UFH (and also have seen your other post about ASHP), if you get a heat pump that can reverse you could do both via the UFH; heat the slab in winter and cool it in summer.

Not much further forward, currently waiting for the structural engineer to finish a few pieces before we can fully engage a timber frame suppliers. We're in London.

If you are happy with them, could you share who supplied your external blinds? I think we'll be installing some as well.

Thanks for all the info. We are looking at an Oso cylinder having seen it mentioned on the forum.

Our architects are doing the PHPP modelling so I'll ask them for the cooling load. We are currently aiming to be certified.