SBMS

What were your ground conditions? We are on clay and worried about ground heave? I don’t know how strong beads down to foundations would be?

Thanks. Out of interest did you leave any airgap from top of concrete to the beads? We are probably going to put a cavity tray across the top but wondered if you can fill the beads all the way down to top of concrete infill?

Hi Foundations done and our block and beam floor is down. We are having EPS beads (standard masonry construction). There’s currently no cavity infill from top of foundations to top of DPC. Building control weren’t bothered but some people are telling me we should concrete infill (up to 225mm below top of DPC), in the event of ‘ground heave’. Is this right?

It was around 400k

This seems really high. Our fees from buildstore: £300 broker fee £1500 lender arrangement fee £105 lender conveyancing fee £200 discharge fee £20 chaps fee £500 valuation fee We chose to go with an advance stage mortgage where funds are released in advance and the application is packaged and underwritten with an insurance policy and paid an additional £3k on top of this for that type of mortgage. This was 12m ago.

You could go direct if you’re good at scouring the market and finding the cheapest rates yourself and have a simple financial situation (full time employment, employed). If you deviate from this (self employed, company director etc) and have a more complex financial setup with regards your income sources I think a broker is highly valuable. For example, if you’re self employed/paid through dividends some lenders assess your income based on your tax return income, others on net company profits. This could make a huge difference to what you can borrow and it’s very difficult to ascertain which lenders use which method without phoning them all up and asking. Secondly, I would recommend someone like buildstore if you’re looking for an advance stage self build mortgage as this mortgage requires an assessed build budget and these sort of brokers have an in house team that can help with this. All in all, I would say a broker is worth the few hundred that you spend in fees.

We had to have this. Attenuation via stone system with a hydro brake to slow discharge into the ditch. On clay.

We had exactly the same setup (including the Nibe 12kw) specified for our build. Was priced up in January and came to 11k for supply and install. Yours seems high but I know that ASHP have gone up. Be careful re lead times - we had to order our Nibe in April and earliest deliver is September. FYI At 11k less the 5k grant I think the equipment cost is more than the net £6k.

I think you should be able to get a simple self build mortgage, just because you own the plot doesn’t preclude you - it’s probably viewed more favourably by the lender as your LTV would be much lower. We borrowed to purchase plot and build house. That will be calculated as part of your equity and therefore your deposit. What I would imagine is that most lenders won’t lend for the site preliminary costs which demolition might be included under but it sounds like you can fund (and prove you can fund) that portion. Is there a reason you’ve been told a commercial loan is required?

That’s really useful @joth it’s great to see some real world data. Makes me wish we had gone for a zehnder as I don’t think vent axia’s app shows as much info as this.

Not necessarily. Radial will eliminate crosstalk but may be noisier due to a smaller ducting radius (more air resistance - noisier). We went through the same dilemma when picking our MVHR design. We ended up opting for branch with rigid metal spiral ducting. We’ve got crosstalk silencers as well. One of the things that you have to be careful of with semi rigid radial is making the bends too acute and introducing resistance and noise. Rigid ducting have pre manufactured bends which maintain the designed air flow. If you dont have web joists you could struggle with a branch system as they use higher diameter ducts. If youre self installing, radial might be easier. I don’t think one is better than the other I think the things that impact your decision are: - joist size - ducting routes - self design or pro design - self install or pro install If you’re going radial you would have a better chance of self designing it, but you’d still need to calculate ducting runs, air pressure and extraction rates (and need to certify it meets building regs). If a branch system I would get it designed as you have to simulate intake along the branches and main trunks to determine ducting size. And you’d have to be sure about where your crosstalk emerges and silence those (usually bedrooms).

I get you. It’s difficult to draw any actual conclusions, for comparing overall effectiveness I mean. If the electricity usage of DCV was 10kWh then 50kWh for MVHR is negligible for say, a 6% energy saving on a 10,000 kWh annual heating demand.

I might be misunderstanding but is the report saying that although MVHR ‘saved’ 6% of heating energy, 5x of this energy saved was utilised in powering the system? Ie if it cost £1000 to heat on average and 6% equates to £60 saved; are they saying it cost 5x the savings to power the system (ie in my example £300)? If not I’m not sure how the two things can be compared.

One thing to remember is that ideally your ductwork needs to be within the heated envelop of the building, or you need to make sure that your supply/extract ducts are well insulated in the chimney void - or that you insulate the chimney void before installing the ductwork.

Seems high. Our foundations have just been dug on our build. All contractor managed: House and garage strip foundations excavated and concreted - £17k Build to DPC on house and garage, drains and scaffold mat - £12k Block and beam to house and concrete slab for garage - £10k Services for water and drainage etc were brought to our site at a previous phase but still our groundworks are less than 40k this is for a double garage and 12m x 11m footprint house.

Hi all Just looking at where we can position our Nibe F2040-12 Heat pump for our build. We have a side path down the side of the house which s about 2m wide and has our gable wall one side and the neighbours fence the other side. At first I thought this would be a good place to put it, but reading the installer page, Nibe seems to recommend 150mm rear clearance (fine) and then states "Clearance in front of F2040 should be at least one metre" but then in the diagram shows free space in front of 3000mm (see page 8 of https://www.nibe.eu/assets/documents/16900/231844-5.pdf). 1m would be fine (150mm rear + 400mm deep unit = 1450mm clearance on our side path) but not 3m. Anyone got an idea what the recommendation is?

Correction sorry, just checked my spreadsheet , these prices do include services

This price doesn’t include water and electric connections (electric £1200 and water is £500). North west (Lancashire) so we do benefit from northern prices!

This was priced up by our builder in March so fairly recent. Things like our engineered joists, block and beam floor, bricks, blocks etc are locked in prices. Excellent question though and I don’t know how much price contingency in supplies our builder has built in. Most of the trades he uses he has used for years so am pretty sure labour costs are secure - but you’re right about things like concrete etc which I know have gone up in April. I think once we are out of the ground I will be less worried.

So you don’t have any internal room stats?

Yes I think there are just two circuits - the UFH and then the upstairs rads. I’ll ask the installer.

Our ASHP installer has currently specified a 300l cylinder and 100l buffer for a Nibe F2040 12kw. House is 280 sqm internal. UFH downstairs radiators on first and second floors (8 radiators + 4 towel rails).

I was reading heatgeek.com and they mentioned that many heat pumps with advanced weather monitoring don’t need an internal thermostat or temperature probe to work out the internal temperature for modulating the heat pump: “Advanced weather compensation can obtain accurate room temperatures without any internal reference once you've dialled your weather compensation curve in. This means it continually runs rather than being flicked on and off by a thermostat, which minimises flow temperatures and cycling which of course maximises efficiency. “ Can anyone explain how it does this? Does it look at return temperature heat loss or something to do this?

Thanks - do you have a buffer? Am thinking it might be tight to get a 100l buffer which our installer has specified, in a cupboard this size (if we can’t do what Johnmo suggests)

Hi all Just wondered if anyone can give an idea of the smallest 'cupboard' required to house: 300l cylinder 100l buffer (for the ASHP) Plumbing gubbins for the ASHP We have currently set aside space in our utility on the ground floor of approximately 1m x 1m internal space (full height ceilings). I think we might be being optimistic but this cupboard has stolen space from the downstairs WC already so hoping we don't have to steal any more. Does this sound tight?