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+1 on the main issue with dot & dab being air-tightness. Builders tend to botch this by using the plasterboard as the main air-tightness membrane, and if you've got any cracking in or voids in the blockwork mortar lines (which you nearly always do) then you get convection cycling behind the plasterboard which just pumps heat out of the house. There are some good FIR camera walk-arounds of which show this. Far better to directly plaster or alternatively seal the block work and then batten out to carry the board. We keep our house at ~ 23 °C and I accept that we may be paying a 15-20% premium for this but that's 15% of a small bill anyway. The problem of 0.18 vs 0.12 is a more subtle one of tipping points. We loose minimal heat through our walls so we don't have or need any installed form of CH on the upper floors: no radiators, boilers or CH plumbing and this saved a lot of installation complexity and cost. You should use a Jeremy-style heating spreadsheet and have a play with the parameters and sensitivities and see what the correct mix / trade-offs is for you. Having a truly energy efficient house (if done properly) doesn't add materially the overall costs because of the consequential savings that you can make. Architects will design crappy performance houses, builders will build sloppily because that is what they are used to, and building to an energy efficient standard is just an inconvenience for them: this is the culture of the UK construction industry. But you will need to live with the consequences every day after you move in.

Today was the day - after a lot of taping etc two years ago we found out today how good it all was. I've not had the paperwork through yet but the tester said the Q50 reading was 1.29 - not sure what this means but the air changes per hours came out at 1.1. Well pleased with that. Not too sure what others on this forum have achieved. I suspected it must be Q good because the house keeps warm with very little heat input. The weak points were french doors (bad - need to see how to adjust them) - 2 pairs of these. And there is a leak somewhere on an internal wall (?) but I've decided that we are not going to try to find them. Just need to move in now. Hope everyone is well, CC

Why..?? Use single skin Catnics straight off the shelf - they are all available and you can use either concretes or steel box lintels on the inside blockwork (or both for high load areas) so you don’t need an SEng to do it but you’re talking about £3-400 tops for all the calcs anyway as it’s all standard.

brick slips are thin sections of genuine bricks that provide the same look as conventional brick work which are commonly used to replicate the appearance of a conventional brick wall in both internal and external applications.

Pics as requested,, as above, don’t forget your the client, they are building/working fir you!!, ask as many questions here as you want, lots of knowledge here ?

Would this be good to use? Tanking Slurry Waterproof Cement Based Coating 20kg | Builders Merchant Direct (bmdgroup.co.uk)

Is it desirable to anyone else, i.e any other neighbours that could tack it on to their garden? If not, then the sellers have a pretty limited market, so the value is whatever you're prepared to pay!

I think he means the heavy end of medium i.e. a block around 15kg. A truly heavy block is about 19kg.

So why build something very unique if you’re not staying in it..? Medium blocks, 150mm cavity, blown beads. Quick, cheap, simple and meets regs with no additional effort.

The original dwelling will be the current dwelling.

7n concrete blocks ??

Depends on the loading. Which way do floor joists run ..? Which wall is holding up the cantilever ..?? What blocks are you using elsewhere ..? Lots of openings at ground level makes me think you’re going to be using a fair amount of steel to hold that up which will cause point loads on the inner skin and you need to work out what the outer skin is doing in relation to that. I would be using heavies on the outer skin as a matter of course as they are cheap and sounds like you’re going to need to do a lot of load calcs anyway.

Further update today. The area around the WC is much improved, so much that I had to turn up the thermostat there. Historically I ran it 2-3C lower than the rest of the house as it was so much colder in that area that if I ran the thermostat at 21C the heating would hardly ever turn off. What is weird is even once all sealed up I could still feel a slight draught in the roof cavity. This got me thinking to the windows and is air coming in around the windows. Now my windows are sealed to the render on the outside, but thinking about it, they are still attached to the cavity behind that, so air can still get in from the cavity. Watching the windows being installed, I was going to ask for them to be taped up, but the builders put plastic sheeting around the frames and taped that up, so I thought they had air tightness sorted. I cannot remember exactly what the detailing was. You can see the plastic poking out in the picture below. Looking at it, I think the plastic is designed stop air getting into the rooms. And indeed we have no draughts anywhere. But what it does not stop is air betting behind the plasterboard. I have been investigating in the gym, as the wall is getting beaten up by gym equipment anyway. If you look at the first IR picture taken on a very cold day, you can see the window reveal is cold, the outside wall which has insulated plasterboard is warmer and then the partition wall which has plasterboard on dabs on a block wall seems have cold air getting behind it. At first I tried sealing up the corner there by pumping foam into the small cavity. This improved but did not fix things. Any I keep thinking where is the air coming from. I pulled out a spotlight and I could feel the air was moving above the ceiling. So as I am already suspicious that there is an issue around the window, I cut a hole in the window reveal What I found was immediately behind the wall I hit the green plastic sheet. This was doing its job of stopping air getting into the room. But immediately I punctured the sheet, I could feel the cold air behind it. The problem is that I think the sheet is sealed to the plasterboard in the reveal not to the block wall. Thus it lets cold air get behind the insulated plasterboard. This air can make its way up into the ceiling void and along behind the insulated board coming out behind the skirting and round the corner behind the non insulated board. I have pumped the area behind the plastic sheet with foam. If this works to stop air getting behind the plasterboard, I will have the simple but laborious job of drilling holes in the window reveals and filling them with foam. I suspect that this has a larger impact on the air tightness test than heating costs. There are no draughts anywhere from behind the plasterboard into rooms that I can feel, other than occasionally at the bottom of the skirting board. Thus the amount cold air getting into rooms under normal circumstances is small. But I am probably heating the air in the cavities constant which will be increasing my costs. When you run the air tightness test the higher pressure involved starts to draw air out under skirting and in other places that are tightly enough fitted to stop normal draughts. As an example of the lack of actual impact on heating costs, the heating has never been on in the gym shown with the cold air behind the plasterboard. There is a UFH manifold in the wardrobe and the heat it generates seems to be more than enough to keep the room warm. Indeed we usually have to open the door when we exercise. Even below 0C outside the temperature in that room stays above 20C.

I looked at the JS Harris heatless spreadsheet with similar U-Values to quoted and changed the internal temp from 21-23C. If you think about it, the average outside temp in the UK might be around 10C, so you have changed the temperature differential from 11C to 13C, which is an 18% increase in the differential. However, you don't have your heating on all year round. I assume that there are 7 heating months with an average outside temperature of between 5 and 6C(using Edinburgh where I am). Thus you are increasing the differential from 15C to 17C which is a 13% increase and pretty much where the calculation came out. I certainly find that I only have the heating on around 7 months of the year. Solar gain provides enough heat the rest of the year. Indeed one issue with heating to 23C is that it might increase how many days of the year you need to run the heating and I did not take that into consideration. That could add another 5-10% to the heating bill, although as discussed on other threads ASHP would be much more efficient on those days with higher outside temps. If you look at JS Harris spreadsheet, and this is somewhat design dependent, heat losses tend to largest to smallest - windows, ventilation, walls, roof floor. The sample house I have in the spreadsheet is my parents' which has a lot of glass, otherwise ventilation would probably be first. Changing the wall U-Value from 0.18 to 0.12 reduces heating requirements by less than 5% and I wouldn't get hung up about it. I would be much more concerned re air tightness in a block built house with dot and dab plasterboard. It is or certainly can be. I deliberately run the flow temps hotter than they need to be to make the system more responsive. Using a gas boiler this does not have the issues of reducing the COP that would happen with an ASHP All kinds of things go into the responsiveness of UFH - Slab thickness, flow temp, floor covering and so on. Rooms in my house with wooden floors take hours longer to warm up than tiled rooms. We have 75m screed with warms up faster than having UFH in 150mm of concrete slab. However, now that I have been in the house for a long time and experimented a lot with the heating, what I find is that the heat loss of the house is the main determinant of my gas bills. Thus I just run the heating at 21-22C all the time. It costs maybe 5% more than sometimes letting it cool down and then warm it back up again (you would sometimes benefit from a smaller temperature differential as discussed above, but the house doesn't cool down enough really to benefit from that which is what happens in an older less well insulated house), but with an offsetting gain in comfort with never having to wait for it to warm up. Thus in @Matt60's case I would probably run it at 22C all the time and it wouldn't take long to get to 23C if required. I also suspect that in real life a new better insulated house might feel warmer at 22C than an older house at 23C.

£35 for blocks £20 for concrete £5 for steel £5 for pump Plus labour, scaffold, bracing. £80? Can I have his number please?!

Reading the above D&B route would be a good option for you (One point of contact ) While the tendering system can push the price down It would be worth spending on a independent professional to compare the quotes As very often the lower quotes have items missing

IMHO all aircrete is rubbish, as I said I wouldn’t use them if they where free, beer or no beer.

Welcome. The best way to start here is with one simple question - such as (say) How do we dry this wall out ? And perhaps post some photographs. Good luck! Ian

We need to make use of small spaces like this to help us meet the need for more housing. Good luck.

hello, and welcome. Don't worry about your grammer, i can't spell. I have no clue about spellchecker, and i can only just use a computer.

My builder charges £80/m² for building ICF (standard ICF block for a simple wall inc openings). I think the Amvic blocks work out at about £35/m² for Joe blogs.

As predicted - the rain stopped as soon as the Brickie topped us out! Little celebration. Roofers were already on site and working like men possessed! Solar panels fitted and today will be their last day. All of a sudden we are back to making decisions and chasing up suppliers! We now have to get our house on the market as we are fast running out of money. Anyone want a completely renovated (new roof, rewired, completely re plumbed throughout,) clay lump cottage in Norfolk? Plenty of room to extend

Watch the videos about the denby dale passive house from green building store. Here's the first one in the series. It's an hour spent that will make your house comfortable fro generations. Also whoever is doing your insulation calculations is telling you porkies. At a quick take your floor comes closer to 0.14 W/m2K nad your wall 0.2W/m2K. Ditch the dot and dab. It's terrible for airtightness.

It's not me that is hung up on anything, I know sod all about this. I have an architect, bricklayer and builders merchant who have all independently said the same thing, and I do not have the knowledge to challenge it or suggest an alternative, though I have suspect there are some from the outset. I get what you are saying re brick arches, I think but cut bricks into slips when glued.... not the foggiest. Yes please, do post - simpler the better, nothing to prove, I know lots about stuff I like and need to know to earn a living, but very little about this. ?

Hiya all, Me and my wife are looking into our first self build. This is completely new to us. My Wife is an Early years nursery worker and I work in IT. We are looking at building a large 4 bed home using ICF in a rural location. Heating GSHP Block and Beam flooring Electric Mains & Solar i have family who can help with foundations and who work for Howdens. but that about it. We are having difficulty pricing the build. If anyone has got any hints and tips on how to set a good build budget, id be more than welcome. As ive said before im an IT Geek, so happy to help and advise anyone on anything techy incluyding home networking, home security etc. Thank you Dave

They are just ignorant. Get it spec'ed up properly and submit it, basically they are holding you back because they don't know. If they were smart, they would let you do it and learn. Typical public sector worker.

Disjointed thoughts since it's late and I spent 4 hours on the phone today: I'm really not convinced a Sunamp is any better than an unvented hot water cylinder for 90% of people - it's a lot more money for a small space saving. Unless you're building on a very compact site you're going to be much better off with a cylinder. For the capacity they're quoting 4-6x the price of a comparable cylinder. I'd suggest a fan heater or something would be a far cheaper way to be safe - you're very unlikely to need the safety if you do your sums right and it'll cost you a lot of money up front to build in that safety margin with a heat pump. If you're fitting MVHR you can get post heaters which go in them for a few hundred pounds, capable of providing quite a bit of extra heat (the Passivhaus standard is essentially written around one of these heating the whole house). I can't remember the last time I saw a wet heating system leak - I've got 1970s pipework at the moment which has all sorts of problems but leaking isn't one of them. Sounds like an excuse to sell you a dry heating system. I would question the value of being able to control the heating system from your phone - it sounds like a lot more hassle than a heating system that just sits there and does it's thing without your intervention. With a well insulated house, there really isn't much benefit to turning the thermostat down during the day (particularly if PV is most available then), so you may be as comfortable and have less to do with a very simple thermostat. The bit about "German style electric storage heaters" is pure snake oil. I wouldn't worry about two circuits - oversize the radiators upstairs as much as you can (good for heat pump efficiency), and you'll presumably have a mixing valve for the underfloor heating anyway to bring the flow temperature down from that in the upstairs circuit to what you need. Remember that heat will rise within the house so you shouldn't need as much heat from upstairs radiators as you would from ground floor ones. Several people on here use Willis heaters for the underfloor heating, with Economy 7. The only reservation I have is about your insulation - 150mm of mineral wool isn't all that much (~0.23 U-value) and using direct electric heating might be expensive, those who do it are at or close to Passivhaus. Check the heat loss calculation before you decide.

So... in the end I needed a proper saw, and even then it was so powerful it was chipping at the end of each cut. Luckily, on the side I didn't need. I don't think I will ever buy these tiles ever ever again!!! haha..... 100 x 100 x 1 porcelain. Nightmare - i'm sure easy for a pro, but this is only my 2nd time tiling. Most are now laid (had to lay a few before kitchen fitters came the following day). I also done all the cuts for the step (And laid one row). I leveled all tiles to the highest point on the step and used a self leveling cement to take up the difference - before I tile the step itself. And that's where I'm at now. Builders didn't leave such a level step and also some concrete was taken away when they done a repair job on the underfloor heating. Overall, happy with it - but don't think I ever want to use such large format tiles again.

@OP. If you intend to collect waifs and strays of the car world like Terry you will need about 4 garages. One for a tractor. Two for the two halves of the other car. And one to rebuild it in. Then the real car can live on the drive.

Thanks, this is from BASF - they have a wide range of products for use with EPS inc concrete admix https://www.master-builders-solutions.com/en-gb/contact/persons/27 if you need a contact

You could try a smaller cutting wheel - I believe its an 8mm wheel that is recommended for porcelain.

Even at the localised 200mm thick EPS below the beams the U value is still better than Building Regs, so I wouldn't characterise it as cold spots, and certainly not "majour". But it does need to be taken into consideration when calculating the whole floor U Value, just as timber fraction does when considering the whole wall U Value. Taking my floor as an example, I have a 475m2 slab, of which 79m2 "only" has 200mm EPS underneath, due to integral beams. But 396m2 has 300mm EPS underneath. So 83% at 300mm thickness and 17% at 200mm. The overall effect on U Value is quite small. Your suggestion is to remove the top layer of EPS and have the 100% of the floor with 200mm EPS. Still an OK U Value, but not as good as good as keeping the reductions localised. It's really not a lot of work to set out the EPS formers. I believe AFT allow 3 days for 3 people to get from compacted sub-base to concrete pour for an average slab. There's really not a lot of work to do the whole floor with beams, so very little to save by not doing the beams. The additional reinforcement would still be required to strengthen the slab where the load bearing walls will be sitting.

Gentry? Fergie? Or does she not know?