Nick1c

Just as the weather turns we are ready to put in the UFH piping & think about pouring the slab..... I sent the details to Wunda, asking for three zones, a Wilo pump and probes to put in the slab (thinking that it would be useful to know the slab temperature if using active cooling to ensure it stays above the dew point). This is what they have suggested: Specialist Tools Components Qty Wilo 22kW Yonos PARA (A) Rated 1 WUNDA PUMP STATION - Wilo 1 Isolation Valve (Red) 1 Isolation Valve (Blue) 1 6 Port Manifold 1 12 Zone Wiring Box 1 Actuator Valve 6 Touchscreen Digital Thermostat 3 Floor Probe 3 Perimeter Strip Insulation - Screed (50m Roll) 1 Perimeter Strip Insulation - Screed (25m Roll) 1 Cable Ties 10 16mm Wundapipe (80 metre coil) 5 16mm Wundapipe (100 metre coil) Having spent some time reading the UFH section on here & also looking at @JSHarris ‘over thinking things’ part of his blog I have some questions. - is it worth zoning the gf at all? It will be a 3 bed, 2 bath, reverse level house with near Passivhaus levels of insulation and good air tightness, there will be 2 people in it for most of the time. - as the slab is in an eps raft do we need expansion tape? Doesn’t the eps have enough give? - is the in slab probe a good idea (it’s all of £5 IIRC)? Anything else to think about? TIA

Floor to ceiling glass is loved by architects & is great for drama. It is also expensive, thermally inefficient, increases overheating potential and may well reduce the useful space in the room. If you have jaw-dropping views think about how best to frame them, from a practical point of view you could probably halve that amount of glass & still have more than enough light. It seems particularly extravagant in bedrooms. Having said all this our house is pretty highly glazed......

We have a fridge magnet we stick on the door of the dirty one ?

We have 2 compact ones. There is only 2 of us in the house so one goes on every day or two, if people come round we can use both. We tend to use the same stuff most of the time so it rotates from the clean to the dirty one. I wouldn’t go back to one.

Thank you @JSHarris, a mat well is something I had originally thought of & promptly forgot. I am struggling to see how to make one though. @HerbJ I searched for that phrase in the forums & generally & nothing came up.

Like @Visti we are having a power floated concrete floor on the ground floor of our house. This is being done before the frame goes up, there are benefits to this but also problems.... The two major ones are shuttering related - the front & sliding doors need a rebate to allow a flush threshold and we need 2 shower trays to be fitted in the floor later. As far as I can see the options are either to shutter the voids accurately or not shutter the door thresholds & make the shower void too small & use a diamond cutter to make them later. If we go for the accurate option I am worried about getting a clean release at the edges & the door shuttering’s stabilty as it can’t be supported on the inside edge (& getting it right!). If we cut after the floor is in the inside corners will be hard to finish cleanly, but a multitool might do the job. Visti, did the shower tray method you showed work and is there any tips you can offer? If anyone else has started with a finished concrete floor before the frame went up what did you do?

Thank you.

@jack I did have a look back, but not far enough so thanks for the links. I have decided to go through the wall for the ASHP, it allows more flexibility. I am using a hockey stick bend to bring the water pipe up so it sits easily. The electrician has asked for 100mm pipe to pull the armoured cable in. As the ffl is below the level of where the duct will start I assume I should drill some drain holes where it is sitting in the MOT to stop water getting in the house! @JSHarris would the loft area be too hot? There will be 400mm of warmcell above it so the only real issue I can imagine is if the inverters generate a lot of heat. There will be MVHR ducting up there so I assume it could be ventilated to a degree if that would help. Where do these things normally go? @joth thank you. The house is reverse level with the kitchen above the plant room so hopefully not a problem.

Would it work going through the wall for the ASHP, or are we better ducting it in? Does the power duct need to be black & is 110mm soil pipe overkill? What about the Pv?

The EPS is about to be laid for our slab and I would like to check what needs to be brought in through it & how. The house will be all electric with an ASHP situated directly outside the plant room. It is being built from panels pre-filled with warmcell and will be timber clad. Water - 32mm MDPE into the plant room. Does the MDPE need protection in the concrete? Electricity - ducting for armoured cable to the consumer unit. 110mm soil pipe with swept bends? Or does it need to be black? BT - ducting supplied by them. ASHP - either 2, 75mm, ducts for flow & return plus one for power & comms, or none & do everything through the wall? Pv - no idea how that comes in. We will have a smallish loft space at one end of the house. Is it sensible to bring all the cabling to the inverters into it & site them there so it is easy to check individual items for failures? WRT sealing the ducts is it just a sprayfoam job, or is it worth filling them with eps beads? How do you stop them filling with water before they are sealed, or do you just not worry about it? Any information gratefully received.

WRT the position of the extraction, what is trying to be managed is in hot air, which rises. Therefore the optimal position for the extraction is directly over the pan, the next best one is to the side and the worst at hob level. I visited a Neff dealer to have a look at the in-hob method, it didn’t impress me and the dealer didn’t rave about it either - apparently the claimed efficiency is achieved by having the extractor on for 30 mins before starting cooking and with no order air movement, hardly a real world environment. In our particular case the island isn’t centrally located in the room, which is on the first floor with the ceiling following the roofline, so we don’t want a ceiling hung version. The.Novy sounds like a potentially good compromise, as does a Gaggenau lifting extractor (£££?). @vivienz are you pleased with it? It’s a lot of money, but potentially justifiable if it does 2 jobs well.

It might be worth checking the regs. I have a vague memory that a conservatory isn’t allowed to have permanent heating in it.

I am no physicist or mathematician, but it strikes me that from a practical point of view (having a comfortable house with a reasonably stable temperature) there are an awful lot of variables in this which make accurate predictions very difficult, if not impossible. One of these, which hasn’t been mentioned, is the colour of the materials, which would affect the time element - a black surface would behave differently to a white one. Another is airwash. It has reminded me of a quote from an ex-president of the CBI I used to use in a previous job: ‘There is a great danger that because we tend to value things we can accurately measure we risk being precisely wrong rather than roughly right. ‘ Rather than dancing on the head of a pin are we not better served by trying to use materials with adequate specific heat capacity and thermal conductivity, adequate being determined empirically rather than modelled to the nth decimal place.

We went for stainless steel & love it, but the kitchen has a pretty industrial look - the doors are brushed aluminium. The first mark on it felt pretty traumatic, but they build up to form a patina of use & it now looks great (IMHO). No staining, easy to clean & heat resistant.

Why not have a thermostatically controlled fan exhausting into a largish area & fit vents into the av cupboard with dust filters fitted - should keep the kit cooler & clean for not much, the heat stays in the thermal envelope.

I used fire blanks cut to size & ballbearing hinges in our last house & will use them again (possibly with concealed hinges if I can afford it).

The rainscreen is mostly timber (WRC or SILa, tbc), with a small amount of render.

Anyone used them? Our architect has specced them. The weather can be pretty brutal - overlooking the Atlantic close to lands end & he thinks they are needed, I think they are common in these parts. All the windows will be sitting on timber, 2 sliding doors & the front door will be on the concrete slab. If it helps I will do it, but all that lead will be expensive.......

@Dan Feist Being at the end of the country I haven’t seen them - what were your impressions?

Check out Reuter badshop in Germany. I bought a Grohe one from them, about €125IIRC & it's great. That was a few years ago. I bought my bathroom stuff for our new house prematurely as I was worried about b****t in March, megabad wouldn't supply to the uk then, but Reuter did.

I am (hopefully) going with an in roof system in the knowledge that it currently is not justifiable on a purely financial return basis. The rationale is that our ability to self use the power generated will increase over time with electric vehicles & time-shifting via batteries, making the numbers more attractive , a feed in rate may become available & it is a 'good thing'. If we need active cooling they will make the running of it free as I assume it will only be needed when the sun is out! Our roof pitch is pretty much due N/S so we have no ability to change the time of peak generation throughout the day, if we oversize it to 'widen the shoulders' of generation we will use an export limiter if needed by the DNO. I have no plans to install batteries in the short term, but will make provision for it so we can use them as & when they become economic.

I considered doing this for our house with some pretty large panes. IIRC when I spoke to Gaulhofer about it they said that it was no problem technically, but there was a much increased possibility of damaging the glass as the edges/ corners would not be protected by the frame. We are using a TF, with concrete in the mix I imagine the risk would go up. If there are no problems I am sure it would look amazing!

Anyone come across them? They are effectively in-ceiling radiators that can be used for both heating & cooling. Zehnder do them, they require a minimum ceiling height of 2.2m &, subject to cost seem as if they could offer a good solution to temperature control on a first floor. I am waiting for more info, but would love to hear from anyone with experience of them. The web page is below: https://www.zehnder.co.uk/products-and-systems/heating-and-cooling-ceiling-systems/zehnder-nestsystems-radiant-conditioning

I have, more than once. (I think) the main issues I remain unsure about relate to the scaffold being used by more than one contractor, even if it is sequential and what happens internally between different contractors if separately hired and also between 1st & 2nd fix. Does someone with HSE training always need to be on site?

Having spent a good deal of time in this section of the forums the whole CDM thing still looks like a mine field, any help will be gratefully received. ATM the plan is to use the same contractor for the groundworks, slab, frame and a small amount of rendering. I have organised the Windows (supply & fit) and plan to get individual contractors to do the remainder of the work. The issues I am aware of are: As a domestic client in order to enable each contractor to be responsible for their own CDM they need to be employed sequentially, this has the biggest effect early on with the windows & roofing. Both will need scaffold, which will be up for the frame, but the frame company will still be there. I had hoped to include the scaffold as part of the 'supply & fit' of the frame, making it vat exempt (there will be a 10% profit on this for the contractor, but I assume he will get a better rate than me), it sounds as if I might have to organise it myself - but does that change my responsibilities? The alternative may be to do the roof through him (+10% again!), so they are responsible until the scaffold comes down. Once that is done I am left with the internals. The options seem to me to be either have a single M&E contractor so trades can be on site at the same time, or get them on site sequentially (slower). I am unclear about how it works with the lining between 1st & 2nd fix. If someone other the the people actually doing the work has to have overall responsibility do they need to be there the whole time, or are visits enough (& what constitutes an adequate frequency)? Many on here have built in a similar way (since 2015) - how have you managed this & at what cost? I am starting to loose the will....... Cheers Nick