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Following the example of @Weebles last year who we visited, we would like to invite fellow Buildhubbers who would like to come and see our MBC 140mm frame to get in touch and make arrangements to visit. We are located in North Essex about 8 miles west of Colchester. We briefly met @Dreadnaught and @vivienz when visiting @Weebles and we all agreed that seeing a real project was extremely useful. See photos below of the house from the rear + central section - taken just after MBC had completed frame erection and gone home for Christmas (the rooflight is 2m x 1m, triple glazed and weighs just over 180kg - we had fun getting that in place ?). The photo is a bit deceptive in that the ground does not slope as steeply as it seems, the house is set down in the ground - we had to dig out over 1,500 tonnes of soil due to the constraints those nice planners put on us ? - and there is more to come out once we start landscaping: At the moment we are reaching major milestones every month or so. November 2018 saw the slab poured, December 2018 the frame was erected and (most) windows/doors installed and PV array on roof, January 2019 the slate roof was nearly completed (slating should be finished this week). About half the house has a brick skin and brickwork starts tomorrow (weather permitting) and they are expecting to take about 5/6 weeks (weather permitting – I think I shall be saying that a lot in the coming weeks). The other half is rendered and the rendering team should start preparations within the next couple of weeks. We also have a couple of areas with brick slips, just to keep us on our toes (but that's another story for another day). MBC are due back during the second half of February to install the insulation in the roof and then make the building airtight. All the above means that there is plenty to see in terms of how the house is constructed. We have lots of lessons to share as well. We have contracted with MBC for them to deliver wall & roof u-values of 0.14 W/m2.K (achieved using Knauf Earthwool + PIR for the walls and similar for the roof) and the slab of 0.105 W/m2.K. I also have a belated apology to make to @Dreadnaught for not responding on his previous thread about the 140mm system – we have been distracted by non-build related issues in recent weeks as well as having plenty of build related issues to deal with. @Dreadnaught - see the photo below of the panels in situ (struggled a bit with the light I am afraid)

I went back and checked my calculations from earlier and noticed that I had multiplied by the COP twice. Errors like that creep in when I sneak in an answer whilst working. OK - 1300kWh per month. You have to remember that you don't have any gas. I don't know the exact circumstances in your house so will be guessing a little. I am also using a COP of 3.5 for the ASHP. According to the manufacturers specs, the COP is anywhere between 3 at 2C outside heating water to 55C and 4.7 at 7C outside heating water to 55C. If you only heat water to 35C the COP rises, but I do not know where it is set. Spec below http://www.mastertherm.eu/wp-content/uploads/2019/01/BAxxI.pdf Electricity for lights, cooking etc. Assuming that the average family uses around £500 of electricity a year for these, that is around 300kWh per month(at 14p per kWh). Maybe slightly more in the winter. Adding in UFH pumps and MVHR, this may rise to 400kWh per month. Hot water, apparently the average household uses about 120l per day. Assuming a 50C temperature increase, this would require 7kWh per day. Allowing for heat losses, let's call it 15kWh per day, allowing for a COP of 3.5, this is 130kWh per month at the heat pump. So very roughly 500kWh of your demand is for general electricity and hot water at a COP of 3.5. Thus you are using 800kWh at the ASHP to heat the house. At a COP of 3.5 this is around 2800kWh of heat demand. As I mentioned earlier, I use around 250kWh of gas a day for heating excluding hot water. You are using around 90kWh per day. My house is well but not super insulated and I am still working on closing up all the leaks. You are using around 1.6x as much energy per square metre for heating. Not great but not disastrous. However my house is not cold when I use this much energy. There are really two problems - Are you using too much energy and why is it cold and they are interlinked. I have looked at the heat pump specs, but maybe someone who knows them better could look. 9kW is the output, it seems it would use around 3.5kW of electricity at this level, which is not the same as the COP, but I may be misreading the spec. You are using around 27kWh a day for heating, this suggests that the ASHP is running around 7-8 hours a day for heating. It should be able to put out more than enough energy to heat your house in almost any circumstance, although this would mean running it longer and using more energy. You mentioned earlier that you are home 6.30-8 and 5-10.30. Is this when you are running the heating/ASHP? UFH has slow heat up times. Depending on your flow temperature, thickness of your slab etc you might need the heating to come on 1-3 hours before you want it to be warm. Some UFH thermostats like Heatmiser try to allow for this, but otherwise you have to figure it out yourself. I would expect you to have to set the heating to be on at 5am to be warm at 630am and then again at 3.30ish in the afternoon. Does the house feel cold when you come home, but warm up by 7pm? The advice to run the heating 24hours a day is not quite right, normally what you do is set it back 2 or 3 degrees when not using it and set the heating times earlier than when you actually want it to be warm. Roughly in your case I would set it to 21C from 5-7am and again from 3.30-9pm then 18C the rest of the time. Indeed the COP of your heat pump is much better when the water is less hot, so it may be better to run the heating for longer periods with a lower flow temperature. But this won't work at the moment as your heat losses are too high. I suspect that your pump is not running long enough and driving a high enough flow temperature in the UFH to warm up your house. You can certainly make it warmer and warmer at the right times, but this might drive your electricity bill up by another third. And so where using too much energy and it being cold become interlinked is the air leakage or insulation problems. 9kW should be more than enough energy to heat your house and keep it cosy. But if you have a lot of draughts then there will be periods where the house leaks heat faster than you can heat it up. In extremis the house could lose heat faster than you can actually get it out of the slab and it will be cold.. You can compensate by running the UFH longer and with a higher flow temperature but will use more electricity to do so. You need to reduce the house's heating requirements to what is expected. My guess is that if you fix any obvious leaks and insulation problems you can keep the house warm using the current amount of electricity, but maybe not use less electricity. You are going to use around 4-5000 kWh per year for heating, this is the peak now and 6000 kWh for everything else. Around £1500 a year for all energy use wouldn't be a bad figure if it was actually comfortable in your house.

With terms like "flange", "black rubber", "lube"and "insert" I'm wondering where he's gotten to!

Don't forget we are trying to help @Jude1234 get the heating bill down. To summarise my earlier post, the biggest difference will probably be sealing up all the air leaks, unless some idiot has forgotten to insulate your loft.

Don't forget a lot of people on here aren't the type to compromise with cost a considered but secondary factor. There are some of course for whom compromise is or becomes a necessity but given the choice they wouldn't have. There's then the pure satisfaction of being able to say "I did that and it's the very best it can be!" Means a lot to many for them and their family. Tends to be that the best air tightness figures are achieved by them either doing it themselves or paying close attention to their builder / having a builder who understands and is willing to meet their requirements. Simply put many on here at least are prepared to go the extra mile whether it be by DIY'ing, paying a premium or even having the tenacity (often need) to shop or sometimes wait for the best deal. Many will not like to be told they could have done better. Many builds are a labour of love. Hand in hand of course there's the bragging rights such a build gives you. Then there's the feeling as you watch visitors marvel at the warmth, sound and draughtproof qualities of your build that costs a pittance to heat. Can't put a price on that!

Went with the decking type wall. Don't think the white wall look would last with my kids jumping over it and the frost. Its been in over 6 months and bar a few of the mitre corners opening up with the timber swelling and contracting it has been no need for any maintenance. I done it during the hot summer so the wood was always going to move about so come this summer if I think it needs it I might redo a corner if I could be arsed!!! I have it divided up so some sections are flowers and others are herbs and have another bit where there are lettuce, cabbage, tomatoes, chili's and garlic are planted.

How important is it to have "nothing" at the eaves? Would a minimal overhang do? This is what I have done: The eaves board is just regularised construction timber, fitted before the render. Eventually it is going to be over clad in aluminium painted to match the window colour.

The toilet humour seems appropriate!

I’m here . Taking abuse whilst being innocent as usual ! ?

ASHP can be put out of sight but needs careful design for airflow. A number of commercial buildings use a type of brise soleil type setups with the end gable wall of a building and then vented panels in the roof to get airflow. It can be done but to minimise internal noise you need a very rigid structure.

Hi everyone, The email said I should intro myself, so here I am - please be kind :-) My background is in construction, but I completely lack anything but conceptual information about Renewable energy, so that's why I'm here (thank Google for that). I'm also planning to do an extension on my house, an outbuilding for use as an office and tool storage and a few odds and sods around the gaff (lecky, plumbing, etc.). Anyway, hope you're all well! Cheers, Chris

Haha I like your brain thoughts ? That sounds pretty tough to me! The only thing is keeping the warmth in - my dream land idea is that it stays at a constant temp all through the year. Jesus though, if they were able to break into the first area, I'd have the buggers locked in and suck the air out. May be have a catapult to send them to the nearest farmers field...I hates thieves!!!

@scottishjohn Thanks for that, may be a very small boiler would be the option instead, then I guess it's just the air con I've got to sort. You don't think that's a lot of plumbing for a small space? The only thing I'm not too keen on is extending the mains water, it's not that far, only 30-40m or so. Thanks for that though! @jack Thanks for answering about the willis heater, very much appreciated and thanks @dpmiller for confirming it has a stat built-in. I'm not going for the cheapest option, but the one that offers the tidiest solution and gives me some good savings in the future...in case we stay here for a while. @JSHarris Thank you for weighing in about this - if we're using electric anyway, is it sensible instead to have direct electric UFH instead of a boiler / water system do you think? @scottishjohn Indeed, life is never simple! @A_L Sorry, misread about the 20C you mentioned, my bad. By chance and don't ask why, but I've got around 5 oiled filled radiators and I have a plug in timer/thermostat that controls it very well - so I've got a fall back if funds get too low. The only thing about about aircon is the placement - normally I'd like to place it to the rear or side, but that's not an option. The front will mainly be glazed, though I guess I could just have a single external door to the left front. I'm planning for other half to have her own room, it may not be needed so I thought have double or bi-fold doors across the front would give me the option to have the whole space to myself! Just trying to anticipate things changing! Thanks for confirming the GSHP, if only I could get some bugger to actually quote for it - they seem to not be interested at all (no surprise considering the floor area), that or their website email forms don't work! I still really like having one system that does both heating and cooling (do correct me if I'm wrong that it can!). Computer/monitor power needs, yes they are high because I have to render and video edit and have 3 x 27 inch monitors to power. That's one benefit to the office I rent, I have unlimited electric for the same monthly cost - I'm guessing this is only because the rooms aren't properly kitted out with their own individual meters. To ALL: You've all given me a lot to think about, what a great bunch you are, and on the internet of all places ? Something that I'm still determined to do is go for a solution that heats and cools me, is cheap to run and doesn't look to ugly. Hmm, these things aren't easy! I even had a stupid notion to use GSHP to heat / cool not just the outbuilding but part of the house as well (in the extension), but of course I don't have the garden area for the pipes...Ho hum ?

The S’Fix one is made of recycled bottle tops .... avoid ..! 1600x900 is an odd size in that room as you’ll end up with a very small sliver that will leak. Maybe better to give yourself a decent “gap” that could have a towel rail or similar so consider 1500x900 These ones are good - and heavy too

Sorry mine was a typo meant to say dettol - bloody auto correct

Moister boards are fine Hardy backer is outdated gypsum backer out performs both and cuts like plasterboard They are yellow in colour Bit pricey at £16 for a 2,4 x 1.2 sheet Graet to tile onto No need to seal Easy to handle also

I think he is probably stuck in 1980, if he suggests you render the out side in a sand and cement render, kill him quickly and bury the body in your footings. Im not familiar with stone walls but from what I do know I think it should be allowed to breath i would look for better clarification from a stone/lime pointing type body.

The high speed films of shells vs armour I saw was during time spent at Eskmeals in the mid 1990's, looking at their proofing capability. We were looking at rationalisation (weren't we always?) and Eskmeals was being looked at with regard to closure. Needless to say we got a very good demonstration as to why the facility should be retained, despite Chisholm's pressure on us to try and find a reason to either close the place or hive it off back to the centre (which is what happened in the end, I think).

Did you know an MOD photographer Nick Coleman?

That has brought back memories from the 80s of modelling long rod DU penetrators v complex armours along with many different CE and HESH rounds.

Yes, it is sort of "self-sharpening". What happens is that when a round hits armour, the outside tends to get peeled back, making the impact point cross-section smaller, increasing the force per unit area in the central impact area. The round may well not fully penetrate the armour, but it tends to deliver enough energy to cause chunks of it to spall off inside, usually at a high temperature, creating a sort of shrapnel fireball inside an armoured vehicle.

yep, 12mm cement board, have a look at the info for another cement board product https://www.jameshardie.co.uk/product/hardiebacker/

everybody makes their own choices and as long as they are happy with them that's perfect and no one has the right to say their choice is not a valid one if it fulfills their design goals and aspirations

Why not use some thing like Aquadry Backer Board instead of plasterboard, to save having to tank?

Details are in Appr Doc L1A and Building Services Compliance Guide - primary circulation pipes for HW services should be insulated even if inside insulated envelope

We are multi talented here so can swing either stick. My wife would kill me if I do any more homers, my wrist and both elbows are done.

last one i bought i got on ebay --unsed -bnib --at half price --so if going that way start goggling

I'm sure it could be done more cheaply with a Willis heater, but for not that much more money I agree that having everything in one integrated and warrantied unit is attractive.

A willis uses a standard immersion element and has a built in stat...

the answer is adefinate --yes --but it might be very small --like in a combi boiler -if its going to run be a non vented system amptec type you get temp control etc all in one package--its what they were made for simple heating solution for a flat

A Willis heater is an inline system, no tank required. You could use a small tank as a buffer if you wanted to. You'd need to check with a plumber as to whether an expansion tank is required given the volume of the system.

ok --so what in reality is the insulation level that is needed in uk -- walls roofs floor windows maybe too much is causing more over heating problems as is being talked about all the time on these threads one for you boffins. trying to build with no heating -to me should not be the goal ,but a comfortable and economical build that most can afford

If you now thinking elec boiler /immersion heater then small dhw water tank as buffer and expansion vessel -job done .nick the plumber will probably confirm or say i,m talking rubbish , and give you better solution but i think you can get small tanks with expansion vessel built in , so then its just plumb to mains pressure + add a circulation pump my reason for using inline boiler is a more accurate constant temp control than a simple immersion element .

Welcome. If you would prefer timber, than i dont see it as a problem. Use the reinforcing mesh that you normally put in the concrete around the inside of say your 4x2 structure. Cheap. Then a batton, then line with 18mm Osb. The only weak point will be the door. I like a thick door frame, double door. One opens out, and the other opens in. Cheap alarm, Solar if no power. Contact breaker on outside door. Keypad on inner door. Scum gets through your outside door. Beep, beep, beep, and sign on second door says. Hi scum. You now have 15 seconds to enter the correct code before my shed starts screaming at you... P.s Please smile for the hidden cameras.

Thank you very much Jack, you've certainly given me more to think about - like you say, so far the only ASHP/GSHP's I've seen are well oversized which would be a waste of money. I really do like the idea of one solution that deals with the whole year round...though having a pump go after only a few years would be disappointing. So the immersion heater route, is there a miniature hot water tank you can buy to put it in, or is there a more inline system available? It would be a shame to need an Air Con unit put somewhere, the roof would be a no-no as the structure will be tall enough as it is. When it comes to building orientation, I'm kinda stuffed, as it can only be set to the back of the garden for practicality, the glazed elevation faces South South West roughly, though I have incorporated a 3-4 foot overhang to the front which should help with solar gain and if budget permits I was going to include a Brisolei. You've given me a superb amount of info and I'm really grateful for you taking the time to write.

this is what i would be using for heat supply in your small build https://electricaldealsdirect.co.uk/heatrae-sadia-amptec-c600-6kw-electric-boiler.html?msclkid=bc823df1a32818b32ba061a8ea6c5a8c&utm_source=bing&utm_medium=cpc&utm_campaign=Heatrae Sadia Shopping AD&utm_term=4583245503759036&utm_content=AD - heatrae sadia %26 Heatrae Sadia Amptec C600 6kW Electric Boiler (EDDSADIA108) presuming you still going UFH only advantage i can really see for UFH in that building is to get more space and flexibility of layout as radiators or heaters will take up wall space

An ASHP is much, much cheaper than ground source. For what you're trying to achieve, you'd be buying the smallest possible unit. You can probably get something for £1700-2000, depending on brand (you might get it cheaper if you're willing to go the ebay route). Installation isn't too hard, and with an installation this size you can probably avoid a manifold + pump (etc) and have the ASHP drive the UFH directly. I do worry that even the smallest ASHP will be so oversized that it will be cycling on and off a lot. Edited to add: ASHPs are fugly, for sure, but usually you can tuck them out of sight. The issue you'll have with your situation is that you can't put it at the back or side of the building, because there's no space. You could put it at the front, but you'll need some form of screen to camouflage it. I wouldn't worry too much about noise: if you're using it, the doors/windows will be closed, and decent inverter-driven ASHPs really don't make very much noise, especially when they aren't being driven very hard (as would be the case with your setup). Given how low your heating requirement will be, I'd really think hard about whether it makes financial sense to go for such an expensive heating option for a space like this. Alternative idea: @TerryE plans to use an ASHP with UFH, but is presently experimenting with a Willis heater to get a feel for how much heating he actually needs. A Willis heater is basically a standard immersion heater in a sleeve, which heats water as it's pumped past. It's incredibly cheap and simple - eg, here's one for less than £50. You'd need to add an UFH pump to this, but it's still a lot cheaper than an ASHP. They're very reliable, and if it breaks you can buy a replacement immersion heater off the shelf for peanuts. In comparison, we had a pump go on our ASHP after less than three years and that cost several hundred quid to replace (had to replace a circuit board and pump together). In your situation, I'd consider a Willis heater driving a radiator or underfloor heating, and wiring up (but not yet fitting) provision for an air conditioning unit that can be retrofitted if you find it regularly getting too hot in summer. You could spend the money you were going to spend on an ASHP on better insulation (as mentioned above, timber frame is definitely your friend given the space constraints), which will further lower your energy requirements. Pay attention to shading so that you maximise gain in winter and reduce it in summer.

@JSHarris has been kind enough to lend me his airless paint sprayer recently, as I've started decorating at the build following on from the plasterers, wherever feasible. I will put some more info on the blog in due course, but wanted to put a note in here in case anyone was thinking about this. I've got a lot of surface area to paint and it's particularly tricky in the upstairs bedrooms where the vaulted ceilings reach 4.7m at their high points. Even with a scaffold tower, painting up there is challenging and I really didn't fancy doing it with rollers. First off, it's messy, more so than the promotional manufacturer videos would have you believe, but no more so than many of the youtube videos I watched on the subject. I wouldn't want to do it in a small room or one with lots of stuff in it, particularly for ceilings, as being able to move about with the sprayer seems to be fundamental to the technique and being able to keep the nose of the spray gun at 90 degrees to the surface being sprayed. That said, for getting the white mist coats onto the plaster skim, it's nothing short of miraculous. Masking takes a couple of hours, depending on what you need to do (large windows in my case) but once the sprayer is up and running, you can get a large room, walls and ceilings, done in half a day as it dries incredibly quickly. I've stuck with contract white for the ceilings - it gives a nice opaque, super matt finish that I really like and makes the sprayer the obvious solution. For colour coats on the walls, I'm using rollers. This is for a couple of reasons - first the sprayer is a thirsty beast and it would cost a fortune if I sprayed the vinyl emulsion, and secondly I'm not sure I could mask effectively enough to retain the white ceilings without overspray from the colour. It also means that I get some texture on the walls, making it easier to touch up any paintwork in the future. If anyone has a new build with lots of bare plaster walls and empty rooms to paint, I'd certainly recommend a sprayer for the mist coats. Do prepare to get messy, though.

The overlay systems need a painfully accurate control system to stop over & under shoot of the set room thermostat set point. These types of floors continuously give me a headache as I get called out to installs for rental / residential tenants who just cannot get their head around UFH, and the usage patterns of. They typically need a higher water temp to achieve what a slab would do with say 10oC lower flow temp, so suffer from the hysteresis of the floor not being accurately responded to by the room stat or the heat source. FWIW, I would not quote for an overlay system as its a PITA to control and an equally large PITA to get a customer / end user to understand how to use it properly. Not a fan, sorry.

Look at it from a heatloss point of view. Assuming an outside/inside differential of 20°C then with 150mm of PIR or equivalent on all six surfaces the heat loss is about 340watts, plus say 180watts for 6m2 glazing, ventilation of 0.5ach with no heat recovery is about 200watts. So about 720watts, then subtract input from solar/bodyheat/appliances. Do you really need a GSHP?

Separate your heating and hot water ‘thinking’ as they’re two very different things. The boiler will be able to do both heating and hot water ( re-heating the hot water cylinder) with ease, even with a kW rating as low as 14-18kW. That 30kW boiler in @nod‘s is very big but will be able to reheat the cylinder a bit quicker. Its the kW rating of the coil inside the cylinder that decides how you convey heat from the boiler ( primary ) circuit to useful hot water though, and you can have for eg a 60kW boiler and a 10kW coil and still be waiting as only 10kW will be conveyed at any one time. Not so simple a question so needs a little more understanding so you can ask the right questions

Fab barn - pics of dog please too. looking forward to hearing all about the renovation. Cant help with any advice, sorry, unless its gardening related but will enjoy ?seeing how you get on. Welcome to the best advice forum on the web!

Might be able to help with some recommendations. I don’t live a million miles from you (we’re Chiltern District council). We’ve just successfully got through pre-planning and are now fine tuning the design before going to full planning application. Our architect is based in Berkhamsted which a I am sure you know is Dacorum and have quite a lot of experience of building on Green Belt sites. Our planning consultant used to run Chiltern’s Planning Dept so knows the ropes very well and has been very helpful....my feeling with him is that if he tells you it’s possible you’ll get it through. We’re demolishing a de-listed house and building a new replacement as well as going for two additional houses on the plot so it’s quite complicated...the boundary for AONB and Green Belt goes right through the middle of our garden. Drop me a PM if you’d like details,

Hello Sam and welcome With vapour control layers the convention is to place them on the warm side of the insulation. You should maybe do away with the membrane against the wall as it may trap any moisture which would be better to diffuse out through the stonework. Just make sure the VCL over the studwork is properly fitted, lapped and sealed. Regarding insulation, Rockwool may be difficult to keep in place if it just open studwork, whereas pir can be foamed in securely.

What you are describing is what I see regularly on Scottish stone houses. Usually done VERY badly. The inside face of the stone wall is way too irregular to just fix insulation to and hope for it to be flat. Usually a 50mm frame is installed, as already noted with the thin studs being supported at intervals with fixings and packers from the stone wall. If you are lucky a bit of insulation might be poorly fitted between the studs before the plasterboard. Usually though nothing. And the last poor detail that makes it so rubbish is the top and bottom of the gap so created is usually open so cold air enters from the loft creating the ubiquitous "plasterboard tent" To do this properly, you need to make your frame fixed to the walls. Then line the entire wall with well detailed and well sealed sheets of insulation paying particular attention to seal the top bottom and all edges (expanding foam?) so no air can enter behind from outside. Then on the inside of your now well sealed insulating box you need to fix battens to create a service void so pipes and cables can all run inside without penetrating the insulation and letting cold in. It all comes down to getting the detail right.

If you want a 50mm thick insulated wall then I can't see this working without the wall being very wobbly. You would want 95mm studs minimum I would think if you are only supporting at ceiling and floor. With a thin wall it would be easy enough to include a few intermediate fixings through to the stone wall to help sure it up. Lots of variable thicknesses of packing material would be needed I expect.

What's the technique, wait till she opens her mouth and shove the ear plugs in still in the bag?

We prefer to store it up and then when it reaches an explosive level vent it in the direction of an injudicious comment from a male!

You are a bad person @PeterW!!! Karma gonna get ya! I’m sure Mrs @joe90‘s contact details must be somewhere! ?

Fit a second stat for her on the wall .... just don’t wire it into anything ....