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Our certificate was emailed over today , feels like another milestone on the build, despite the fact this will be our second Xmas in the house officially we have(now) completed .

You do understand it. It is the U-Value [W.m-2.K-1 or W/m2.K (not W/m2/K as above)] multiples by the surface area [m2] multiplied by the temperature difference [ΔK]. So with a U-Value of 1 [W.m-2.K-1], a surface area of 32.9 [m2], the unknown ΔK, but a solution of 881 W. 881 [W] / 1 [W.m-2.K-1] x 32.9 [m2] = 26.8 [ΔK] To work out the assumed outside air temperature [OAT] you just subtract the external temperature from the internal temperature [IAT] i.e. 20°C. 20 [°C] - 26.8 [°C] = -6.8 [°C or K]. Now that is the power (the W) not the energy [Wh] losses over a set time period when the OAT is -6.8°C i.e. a cold winter day. To calculate the energy lost, you have to multiply by the time in hours [h] to get to Wh, which is how we purchase energy (we purchase in kWh, so need to divide by 1000). Now we do not have fixed temperature differences, they vary over the year i.e. large in winter, small in spring and autumn, irrelevant in summer (they they can be positive as well, we call that solar gain). Temperature probabilities, based on a typical metrological year [TMY] are used to calculate the amount of time spent at different OATs. Now you may have noticed that I have mixed descriptors for temperature, sometimes I have used celsius [°C] and other time kelvin [K]. This is considered very bad practice but is often used to make it easier to read. There is a reason that it is bad practice and that is if you are adding or subtraction temperatures then the scale name makes no difference as the size of the graduation is the same. But if you are multiplying or dividing, then you must use the kelvin scale or you get odd results. This is very important when working out radiative losses and the efficiency of CoP of heat pumps. To convert celsius to kelvin, you add 273.15. So -6.8°C is 266.35 [K]. (We should really use the joule [J] for energy and not the Wh, but that is another lecture)

And progress on one side

As promised, a Q&A, to ask us anything about our Grand Designs project, which aired on TV two weeks ago. Forums like Buildhub, have been an great resource for us to learn from others, and so if this is one way we can give back, then happy to. Much of the 'technical' gets glossed over during the TV show, purely due to time constraints. So if there are specific questions about our building fabric, fire away. Rather than dumping loads of photos here, there's plenty of the process on our Instagram: https://www.instagram.com/thefoxesmaltings/ Disclaimer: We are first time self-builders, and I am by no means an expert, nor do I pretend to be one. There is still plenty of stuff I have no idea about, and plenty of you on here with way more knowledge than me! Based on any answers, I would love to know what you would have done differently, or things we could have done better. Who knows, there might be a next project... And of course, if you missed the episode, you can watch it on demand, on Channel4.com.

Do NOT build it into an accessible space. It has to be accessible somehow e.g in a kitchen, on top of a wall unit etc. Or even build it in behind the light switch and run dc to the light strip?

I think so if it makes a material difference. The key points of MIS 3005 D are that it requires a heat loss calculation to be done with specified minimum interior temperatures, exterior temperatures dependent on location, and 'otherwise complying with BSEN12831-1:2017' Without referring to the latter I don't know what it says, but it would be surprising if it doesn't allow some latitude for accounting for the actual building. Unfortunately its £460 to buy. I doubt many if any installers actually have a copy so they will most likely be relying on interpretations/software produced by others. Thus they may be (and in my experience are) open to persuasion or may dig their heels in, depending on how confident they are in their own abilities/judgement. In the end they know that the MCS rules, followed to the letter, are their protection because following makes them essentially bomb proof. However the better ones also know that pleasing the customer and doing the right thing, with an appropriate interpretation of the MCS rules, is a better way, in most cases, to gain a good reputation.

The thought had crossed my mind

I don't have MVHR, I have a 1930s house with (originally) solid walls, that has been subjected to various fabric upgrades at various times including double glazed windows that have no trickle vents and solid flooring downstairs. MCS ACH = 1.5-2.5 based on age. I ended up with two installers that provided satisfactory quotes. One assumed ACH = 0.5, the other a bit higher (0.8 I think). 0.5 gives a total loss that is consistent with the measured loss (based on analysis of half hourly gas consumption over 2 years), 0.8 ACH works out a bit higher than the measured heat loss, but still resulting in the same design choice of Heat Pump. I understand that decent MVHR has a recovery rate of 80% so I cant see why one would assume an ACH above (say) 0.25 unless its expressly mandated, specifically for heat loss calculations (which is what they are supposed to do) in the British Standard (to which I don't have access) referenced in MIS 3005-D.

I made some edits. I was interrupted by a puking child on my first attempt. Keep the big island. Just make it the focus of the design, not an afterthought. Ours is 3.2m long and 1m deep and it's fantastic. I've the hob at one end, all pots and pans under it, oven directly behind, bins, chopping boards, knives etc just a step away. Sink almost directly behind as well. Keep the sink at the window for sure. Try to picture using the kitchen day to day. What happens when somebody is cooking at the hob and transferring food to the oven while somebody else is making a cup of tea? Do they ever occupy the same space? The answer should be no. That's how we designed ours, designated zones by activity type. A rendering of ours. The door on the LHS past the fridge is in to our boot room / pantry.

You must have the patience of a saint , three and a half years to try a resolve a boundary issue regarding a fence built on your land ! I can only echo the opinions above, if its your land then you are entitled to remove the fence (or anything else )whenever you want and you do not need to inform anyone what and when you intend to do it .

Plus 1 If it is on your land Your muddying the waters by getting the LA involved Contact a solicitor and give them thirty days to remove it Though I probably would have driven a tractor into it by now had it been on my land

@thefoxesmaltings thank you for contributing so much specific detail/answers - very useful. I understand (from another much older post on here) that you did a shadow gap rather than skirting boards - we're currently considering this (I'm leaning towards a shadow gap). Any lessons or advice we need to consider early in the design drawings stage if we go for a shadow gap?

Surely it’s just going to be a manufacturer recall, guy will come out with part and not care whether it’s faulting or not, just replace it…maybe play dumb if not and say that’s what you were led to believe

In the end it turned out that the (brand new) driver was the issue. I got send a replacement and now all is well!

Another happy MBC owner here. We put some extra 11 cm pipe runs down from the plant cupboard under the slab and out beyond the peripheral path . We ran various services through these using various flex sleeving covers. These proved great during initial build, but were flawed for future additions -- basically after 2 years of external ground-works and landscaping the external covered pipe end got lost / buried too deep / covered by paving etc. We had a rule that no trades were allowed to breach the twin-wall, so we did all the through ducts / conduits then once the sparky etc had done using them we foam filled and silicon-sealed them all before the pressure test. I only wish we'd put some extra through pipes "just in case" as well. There are no air leaks and tiny U-value hits doing this to it;s a damn site easier drilling one of these out if you need to add extra services later than trying to add a new airtight through duct once the building has been boarded out and plastered / outer skin complete. I ran power and Gb enet to a small shed close the house and added a PoE switch here so that all of the external cameras etc. could be cabled to this shed.

It may be worth stopping all work, then applying for planning consent for a replacement dwelling. Your friend should be eligible for CIL exemption, as well as VAT back. The VAT and CIL need doing correctly as the rules are strict.

Too true - too many monkeys not enough craftsmen. The adage 'never do to a customer's house that you wouldn't want done to your own' is one I've always worked to and tried to instil in apprentices, but I've worked with many so-called tradesmen of all types who couldn't give a toss as long as they got paid. Having said that, I've yet to come across any roof that is 100% waterproof but a properly installed and detailed membrane should keep out 99.99% 🙂

I bought this shoveI. It has been excellent for £21. The serrated edge is very good at cutting through things. Have spent three hours so far digging and pulling. The best thing to do seems to be to dig along just past where you think the chicken wire is buried, then you can pull it up like a roll of turf. The problem is places where roots have grown through it, sometimes up to 2cm thick and in one place where someone wrapped it around a large tree and the tree has grown into it, I just had to cut it there. They also just dumped unused chicken wire on the ground to grow into the undergrowth. Idiots. As you pull the chicken wire back you occasionally have to stop and run the shovel under it to break up roots. It has been back breaking work, I have had to put my not inconsiderable weight behind pulling it out. A woman stopped and cautioned me that her dad did in his back doing something similar. My recommendation would be that you should use chicken wire sparingly. I have also been able to perform an archeological study on the eating habits of builders and school children. They appear to really like McCoy's crisps.

And knowledgeable. I've met some very ignorant roofers who don't understand lapping and flashing. Absolutely not a clue, and if was as easy to do it right as wrong. They were roofers because they didn't mind heights and the money is good. (And ceey few clients check the work). All the above advice is good....it must not leak at this stage. Post a couple of pictures and you can honestly say you've had it looked at by experts and they have to sort it and spray test while you observe.

If your boat is of steel construction and not traditional build the extra heat you generate within your nearly air tight pod will feed through to the hull and head immediately to the coldest area's ie. the uninsulated area of the boat. The stern where your engine bay and fuel tanks are. You will always get moisture inside metal fuel tanks, hence why new builds use polymer tanks. If the boat is of traditional timber construction this allows your hull to breath, and the build up of heat dissipates differently.

Might be worth reminding them that this is part of building regs for an MVHR, from memory

congratulations! having recently received our I know what a great feeling it is.

Min amount is just what is required to support normal defrost cycles. It doesn't address cycle times during normal running. Normal running cycle times are governed by min ASHP turndown, and min house heating load. If your min turn down is 3 kW and house min heating load is 1kW the heat pump will cycle on off to cope. The more water volume you have the longer the cycles.

Site visit now done. The inspector was there for about 10 minutes, not sure if that's good or bad! Checked the kitchen/diner view and the dual aspect bedroom. Went outside and asked about the intentions for replacing the lleylandi, which will be a dry stone wall with native planting. He seems to take 3 or so weeks to issue a report. Fingers crossed.

You could double check by putting similar assumptions into Jeremy’s spreadsheet?

We have the Drayton system. 7 or 8 smart TRVs, 4 room thermostats. I wouldn't buy again. We needed three of the range extenders to get to all TRVs and even then some are a little low on range and I get the occasional disconnection notification. The reason it works for us now is that our house is so poorly insulated it means we can warm the rooms we're using, not the whole house, and we can avoid having any rooms too warm (19 is a treat for us - typically rooms are set to 17 and 18 or 18.5 if being occupied). When we have a better insulated, more airtight house I would have regular TRVs and try to size radiators to the room rather than try to zone too much, as I understand in general it isn't a very efficient way of heating. I also hate having to go round replacing batteries. I assumed I'd be able to use rechargeables but they only last half as long before the battery warnings start pinging. I won't buy any smart home products with batteries in future, it only adds to the faff. I also want to avoid anything needing range extenders because reliability just isn't good enough at this point.

there should be a wee squiggle symbol at the bottom right of the display if it's auto-boosting because of humidity

Hello Will. I've not been about much as busy with the day job and trying to get a bit own own house done before Xmas. Excuse spelling and grammer please.. just knocking out my thoughts. I can see you have put a good bit of work in trying to get to the bottom of this. Well done you! For me that is the benchmark. We want the mortar to be no stronger per say. Ok they seem to be taking things seriously. Insurance companies per say.. delay, deny, defend.. a pattern of behaviour which I see on a regular basis. So nice of them.. as they know it will cost you lots! They are chucking enough at you, getting some testing done to see if this will head you off at the pass. Did the report give an interpretation of the results and the knock on consequences SE design wise? Well done you! Smart thinking. And here is your simple way in I think. When we design masonry cavity walls we allow for the inner and outer leaf to interact. This allows us to take an overall effective wall thinkness.. both the inner and outer leaf work together.. which gives us an overall effective wall thickness. This means that both leaves have to reach the design standard. Also the wall ties are critical as is cavity width.. something to check later to make sure the ties have the correct embedment each end. Now if the inner leaf is sub standard and is contributing to the effective thickness of the wall then someone is going to have to prove that the cracked inner block and mortar with extra air is still able to meet the design codes.. and that will cost them a fortune! Now the questions I would be asking are: OK we have a BRE report. But has an SE had a look at this to check to see how the wall was initially designed to resist the vertical and importantly the horizontal loads and if the inner leaf still is able to contribute to the effective thickness of the wall.. especially for lateral wind load. THIS IS I THINK YOUR WAY IN at least expense / risk to you. In som way they have started the forensic process. The NHBC et al do this, get a report that is confined in scope with no interpretive element.. the knock on consequences. I would go back to them and thank then for the testing. Then say can you give me a structural Engineers report supported by calculations that check both the inner and outer leaves for wind loading and slenderness under vertical and horizontal wind loading.. give the information we have on the cracking in the inner leaf and the mortar findings. They need to provide you with an interpretive report. what does the testing / findings mean?.. and I guess at that point they may shit a brick! My gut feeling is that they are intending to appear they are doing something and racking up your percieved risk aspect. It's a game they play... gambling odds. This is going to open a can of worms as the SE that has to sign off on this will want to know lots more! The main thing here is to force their hand and not spend any of you own money at this stage. For me this is a structural safety issue.. and that concentrates minds. Now as a word of caution. If you instructed me to go full pelters to win as much as possible on your behalf then we could find lots of other issues. As and SE I can't sign off on the stuff that suits you and ignore other stuff I find. Depending on how things pan out you may have to make a declaration to your home insurer and you must make sure you don "blight" the property by a simple administrative error. Now say it turn out that these defects are prevelant over the whole structure? What then? That's it for now. Don't act in haste here.

you need a 900mm structural opening for regs these days.

You can buy lots of things, doesn’t mean they meet building regs. that’s a tight door in a modern house nowadays 838mm on every opening here. Except one cupboard.

All our internal doors are 826mm and even that only gives about 780mm clear opening width. Cupboard doors can be narrower and of course a lot of what H sell is for retro fit into older houses and nobody is ever going to check or care. Time to discuss with H and change them for a bit wider?

It's very simple. In the winter when you turn the heating on, for the 3-4 months of the year that you will be heavily reliant on space heating (in the majority of homes) you'll be at <25% or less PV production, so if you have a 4kWp array you'll not be getting even a reliable 1kW of PV production (when it's one of the sunnier days in the heating season ). That <1kW will be sucked up by the house, so there's "goodbye" to any dreams of diverting excess ANYWHERE as you won't have any. If, for eg, you have space & budget for an 11-12kWp array (maxed out on 3ph, for eg) and it's all South facing, then maybe you'd still get DHW from excess. But even with that size array, during the heating season, you'll be very lucky to get a reliable 2-3kW return from the array. Costs of PV then go beyond the costs of just feeding cheap, grid electricity into the ASHP in the 1st place, for dumping steady low grade heat into a big thick insulated raft slab as a 'storage heater'. Get the calculator out, remove the rose-tinted goggles, and the evidence will support itself.

Has your wife caught you looking at @ducthub in the evenings?

On the positive side that really is a beautiful 'duct-forest'! Doesn't need boxing (not that I think you were going to); it's a sculpture!

I know. They said they could come back and do it but there would be a charge - merry f'ing Christmas!

Thank you. Protek are in pole position re site insurance. Wading through the warranty documentation is next week’s job (I know how to live it up at Christmas lol)