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This was a project of mine about 15 years ago, maybe more. It is used by a company you all know. I was there recently as a customer and asked if I could look at the warehouse for interest. I'm really pleased how this is performing after the years of forklift use. No cracks other than the controlled joint which has barely widened. But look closely at the micro cracking of the surface. This is normal and is always there unless covered by paint... and then it isn't exposed concrete. This is why I don't recommend concrete in a house unless desperate to impress on Grand Designs ( who won't return to see it with stains and cracks years later.) And this is a very good floor by utter experts. Bte the few tiny indents are caused by lignite which we get in aggregate.

I had some high spots on our concrete slab, used a diamond disc and a hoover attachment/guard attachment on an angle grinder. Used a Henry hoover which survived. Worked well enough, but time consuming. You will still need a face mask.

@IanR did a poured resin floor that might be an alternative: Microcement exists but isn't cheap. The only other suggestion that comes to mind is exploring commercial concrete contractors rather than 'polished concrete' specialists. I've no real-world experience, just researching for a future build but if you haven't already looked, have a look at https://concria.com/dry-shake-floor/ and their polishing system. Would only work on a large floor area without obstructions, but if thats what you have then might be a lot cheaper than conventional polished concrete.

Concrete can work with the right design. Does need careful thought though and I certainly don't think it's worth a premium price.

So a very heavy warehouse for forklifts and racking? You can do almost anything over that. Your internal walls and even steel columns could go straight on your floor with SE input. Above that I would have minimum 150 pir then a screed with ufh. As prev discussed I don't see the attraction of a polished slab in a house, perhaps because I've built hundreds and see them as functional. I'll find a photo to emphasise this.

150mm allowed for insulation and screed? Insulation below and around the structural slab? Where are you in the project - just planning or kart way through build?

Thanks Gus, I get you now. My reading of this is about taking a wider view of heating design beyond cost cutting via material, initial design input, and doing it in the quickest most convenient way. Instead invest for the long term rather than just look at the engineering redundancy. Yes, whole life cycle makes perfect sense and is ultimately a more sensible approach. And from a design perspective I'd suggest it's more about the principle of understanding the space as a whole rather than what the plans indicate. In this sense it's still important, if not absolutely necessary to vary the design for different areas of the building - e.g. a large living space with acres of glass compared to enclosed individual rooms with small glazing factors, but at the same time look to provide reliable heat distribution throughout the building. Although temperatures will tend to equalise across a well insulated building, there is still very real possibility of localised over-heating if not considered carefully, and therefore the system has to be designed with balance in mind, but not to get distracted by variables occupants can easily change over time. If my understanding is correct, I think we're pretty much on the same page.

Have you thought about a different tariff other than E7? Octopus does one for storage heaters, three cheap periods, one expensive period, and the rest of the time standard tariff. Instead of one long off peak and one very long expensive period. Then just drive immersion via an immersion time switch and allow to tip up every cheap period, so you never run out of DHW. You would need a smart meter and time other heater via a time switch also.

I'm mulling a Fajita brushless jigsaw. A tool I don't use a lot tbh. The s/hand Makita circular saw I bought is a bit gutless tbh. Blade looks alright. Brushes maybe 🤔

The clue is in the writing on the right hand switch. It says "Kitchen switch" So leave the 2 in the cupboard always on. The tank will heat overnight on the off peak. Then IF you have used up all your hot water before the end of the day, you can turn on the switch in the kitchen and that will top up the tank from the peak rate. It saves you having to go to the cupboard to do so.

I think you've still got a good couple of weeks to go at least until the system balances itself out. I would just go weather compensation, fully in the knowledge you'll be tweaking it for the next couple of months.. The problem I've found with running elevated WC with a thermostat is that they can end up fighting each other, especially if the thermostat has modulating input to the heatpump & flow temps. You then get oscillating compressor frequencies and can even see elevated defrost cycle frequency. Obviously this depends on how the controls are designed and implemented. If you go weather compensation only you're reducing your variables and any diagnostics/analysis of system behaviour becomes a lot easier.

the fake stuff is great now- I've got both turquoise and yellow flavours

I've genuine 18V Makita drills (3), impact driver, grinder & circular saw. I've then Fakita grinders (2), sabre saw, multi tools (2), palm router, paint spray gun and 4" chainsaw. I can honestly say I use the Fakita stuff heavily. Had to replace the motor in the chainsaw as I asked too much of it but that's it. The fake grinders were my goto before I bought a genuine one s/hand off of someone on here. Tbh I often prefer the fakes as they're slimmer and lighter as well as brushless. I only ever use genuine 5Ah batteries on the above stuff and other platform stuff where we print battery adaptors.

What are you finishing the floor with? Are the levels generally OK apart from ridges and raindrop marks? How soft is the top? Can you scratch it?

They also have this, which has 250mm dia diamond disc. It's a big enough area, about 70m2. I wouldn't fancy going at it with anything handheld!

That is a bit of trial and error, to see what works for your floor. There is a third option, a slightly elevated WC and thermostat. The ideal is one long run between thermostat trips if you go that route. The 3rd route gives a better overall CoP than a fixed flow temp as your flow temp reduces with warmer weather. Two things to look at, CoP but more importantly is energy input.

We did have some sediment when we did the original pre commissioning wash through but not a great deal. I did that earlier this week first backwards, as you suggest, and then forwards. The flow rate was prodigious both ways at 12L but of course that was at 4 bar pressure, the pump measures just over 0.6 bar. I then ran Sentinel X800 for a couple of hours and flashed that out, then put X400 in and have left that to see if it can do any more. The long and the short of all this work, and taking out any Glycol, is that I have improved the flow rate a little in the long run and so across the UFH by, well, nothing really, about 30l/hr and most of that improvement is probably due to the higher flow temperature changing the viscosity of water (you can see the effect of this in chart below). Anyway I am not too downhearted because we have managed to find a stable operating point at COP of 4.0+ and got the house up to temperature. At the end of that group of runs the slab temperature reached 23.8 deg C and so turned it off because that is about what we want in the final event. Next week I will connect a slab temperature probe directly to the EMON so I can watch it all in one place. Zooming out to now you can see that the house temperature lags the slab by 7-8 hours! Obvs the period of inactivity hist the overall COP but I am not displeased by even that. I am not sure I need to reach for an industrial pump as I think @SimonD was correct in urging patience while the system settles down and I think we have clear evidence that approach worked here. One more thing I found when making adjustments is that the Control on IN / OUT switch actually refers to using external or internal sensor but has no effect, when set toe external, unless you also turn on Weather compensation. So where to from here is my next question. I need to either switch on weather compensation and see if I can tune that or run the UFH in much lower flow temperature chunks against a stat that could be room temperature but looking at it might usefully be slab temperature given the way the system (house / slab/ heat pump) performs although I am not sure.

You can usually hear an immersion heater work by the fizzing sound. So during the day, try keeping the kitchen switch off, and flick the 'Peak Supply' switch on, you should be able to heat some noise from the cylinder, or you can check the meter and see if you have an extra 3 kW load on. The kitchen switch may be just a secondary switch to make life easier i.e. not having to open a cupboard. Most of us on here like to keep water temperature as low as possible to save parasitic losses. I have a 200 lt DHW cylinder and store, via E7, water at 50°C. That is enough for a bath and a shower. Check the thermostats as the upper one (peak) should be higher temperature than the lower one (off peak).

As title suggests, I’m after advice re polished concrete floors, the cost/practicalities and alternatives. project is a barn conversion, we’ve already got a 200mm structural slab which is 220m2 and have allowed for 150mm further flooring but this must include UFH, insulation etc. We would like something resembling polished concrete (mid shine) but are fully open to any other suggestions that don’t cost £100 m2 plus. My contractor is very practical but has limits. any help and advice would be appreciated

I use hotukdeals quite a bit and have alerts set up for the yellow and black tools. Good to get alerted when the offers are on.

Advice please? (Attached pics) Got unvented hot water cylinder in a flat (1995 build) I just purchased, fully electric flat no gas. The unvented hot water tank has two switches... 1 is off peak supply (through the night it runs only- cheaper prices). Other is 24 hour on demand so heats at any time throughout day (peak times so normal elec rates). But...There's a third switch (in kitchen).... So I plan leaving off peak switch on and others off so that tank heats up during night and is hot enough next day as I know if left 24hr on, the tank would constantly heat up to a required temp via thermostat so using alot of electricity... I was told that if I wanted a bath say, and the hot water wasn't as warm as I'd have liked (Ie last heated in the tank night before)I can switch on the 24hr switch for hit water in demand...which makes sense. My question is, following on from above I was told I'd have to switch the kitchen socket (silver switch) on along with the 24 HR supply switch to achieve the on demand hot water? Does this sound right...or is it possible that the silver switch located in kitchen is for hot water on demand to the kitchen sink? Also told if just showering and no baths just leave the off peak switch on and rest off so uses as little electriciy as possible. Any tips on this would be great before I waste a small fortune. It all makes sense just the third kitchen switch is throwing me off a little like why is it there and not just use the switch marked 24hr next to off peak?? Any help much appreciated.

There are many ways to skin this cat....... You know me..... I'm always expressing an opinion due to my 'lack of varnish'

Arms like a fiddler crab afterwards?

Some things to try just to rule stuff out. Ruling stuff out is a good way of approaching a problem. You have 185m loop. I would disconnect that and first gently connect up an air compressor to the return end. Gently blow the water in the pipe into a bucket, see if you are getting sediment and if so what kind. then blast it. That may be enough to clear any stubborn gunk. At least then you know if the pipe is clear. Then connect mains water to the return and back flow.. DO NOT do this on the flow side as you could make matters worse. Check the mains water inlet pressure and collect the water in a bucket. What is the pipe internal diameter you have? if you know that then you have some data on the loop that is maybe a problem. Now you can back calculate the loop characteristics. You can then reduce the mains water to a lower pressure and see what happens. Once you have handle on that you can then see what you may or may not have to do to the rest of your system. It could be that you long loop is ok, it just needs a good clean out! Remeber that as a long loop the flow at the return end would be diminished so gunk could have accumlated over time. Other question is.. did it work before you got your new boiler? Did it work fine when you first installed the system?

Are there grounds for the OP posting the question: “given the suggestion of SIPs should I trust my architect?” In the appropriate forum. Not that I’m expressing an opinion, mind.