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If you’re not driving the digger then your opinion doesn’t matter. if you have an experienced operator and a good groundworker then they will know exactly what to do. don’t interfere too much, sit on the dumper or work the laser, but trying to over manage lads that do this every day won’t go down very well. You won’t know how the corners will hold up until you start, you might come across a big patch of loose backfill,have the shuttering to hand you will dig all that in two days, you need a site visit the second you get 4-5 m of trench to full depth. you do not under any circumstances want to have to go back over it, so you need depth sign off the same day you start. what do you mean by shutter and pour multiple times. that all needs digging in one go and pouring in one hit the following day.

There is a bit of terminology to learn. Energy is measured in MJ (megajoule). A joule is the standard unit for energy and when converted to base units of kilograms, metres and seconds is very small. Why the M for 1,000,000 is added at the front. Now no one, apart from us nerdy scientists, use MJs, and domestic energy is metered and purchased in kWh. MJs can be multiplied by 0.0007778, or divided by 3600 to end up with kWh. The k just means 1000, W is watt and h is an hour, which is 3600 seconds. Power (W) is the rate that energy is used. You can think of this as your miles per gallon in your car, with energy being how many gallons are in the tank. If your car does 40 MPG at 60 MPH, and your tank has 8 gallons in it, you can drive 320 miles over 5 hours and 20 minutes. A unit of power is called a watt, which is actually a J/second. Again a small unit, so a k is added. A k is 1000. This gives the more normal kW for a power rating. Boilers, heat pumps and even wood burners all have a maximum kW rating i.e. 6 kW. Radiators, UFH and fan heaters also have a power rating. (This can get confused by some people talking old imperial units of BTU and BTU/h, but we went metric in ,'73, so tell them off) Where it starts to get confusing is a house will need a varying amount of thermal power to keep it at a steady internal temperature. This is caused by external temperatures rising and falling during the seasons and even during the day. This can be overcome in a number of ways. The easy way, and the way old heating systems were set up, was to fire up a boiler at full power, heat some water, pump it around the house to all the radiators, which then heated the air. When the house was up to temperature, the thermostat turned the boiler off. When the temperature dropped a few degrees, it turned the boiler back on. These days we are a bit more sophisticated and try to deliver enough energy to match the losses. This keeps the house at a steadier temperature, and used less energy overall. You will almost certainly read on hear about weather compensation (WC). This is just a basic feedback system that knows what the outside temperature is, how much power is being delivered to the house and for how long it may be needed. All that can be boiled down to a few numbers. The main numbers you need to know are the thermal losses for each room. Once those are added together, you get a number for the whole house. It is usual to size for a worse case i.e. -10°C outside. This gives you a maximum power requirement (heat source kW). Most of the time, you will be heating the house when it is way warmer outside, so the second number you need is about how much the heat source can be turned down internally. This is called modulation. Gas boilers have quite a high ratio, sometimes 10 to 1 i.e. 12 kW down to 1.2 kW. Heat pumps are not, generally, so good and are often in the range of 3 to 4 to 1. There are ways around this, but that is for later. The other thing that is important is domestic hot water (DHW). There are two ways to do this. Heat water only when it is needed (instantaneous), this requires a lot of power, often over 25 kW. Or Heat and store in a cylinder. This method takes longer for the same amount of delivered hot water, but used less power, often in the region of 3 to 6 kW. If the heat source is delivering both central heating and DHW, then this needs to be taken into account. With modern combination gas boilers, they are sized to deliver enough hot water, and rely on boiler modulation to deliver lower power for the space heating. Heat pumps, generally, rely on being only slightly oversized (which improves efficiency most if the time) and run a space heating time slot and a DHW timeslot at different temperatures and different times during the day. There is a lot of detail in heating design. So questions to ask are. Maximum house losses. Room by room heat losses. DHW reheat times.

Stock piling is seldom a good idea. It ends up being in the way, at risk of damage from operations and the weather, and needing double handling. Nearer to the time of need, ask the BM if any increases are forecast, and maybe avoid 10% cost and store for a few weeks. But I did this recently with insulation. And we had to shift it to suit a change in plan. The handling cost prob equalled the 10% saving. Then there is cashflow. The VAT cost is sitting there needlessly. Spend your time in saving material altogether, through design reviews and planning.

Have you considered splitting the house so kitchen dining runs front to back instead of along the back?

I'm not a user, but https://www.sunsave.energy/solar-panels-advice/exporting-to-the-grid/best-heat-pump-tariffs

I design stuff like this. There are many options. Best advice I can give you is to get an SE on board now, even if to provide a watching brief. If you don't then you introduce significant cost risk and uncertainty. You know there is a potential issue so the sooner you get that under control the better.

Ok that sounds like a good move. Here is what I would do if I was you. Find the best and well repute self employed 3CX digger driver with their own machine that works local. Pay the extra. Get them round and ask them how to do it! Ask them how they want the found marked; inside, outside, centreline or all of the preceeding. Assume the weather is going to be pish and some marks get lost by accident. Set some pegs well outwith the dig so if the marks get lost you can run a string line to get you back on track. Work out what you are going to do if you hit soft spots. An experienced digger driver is going to be your best friend here. They may also say they will pitch up during the pour and can use the back actor to get the concrete in place. Make sure you take plenty photographs. Be careful not to over dig. There are some horrible examples on BH where over dig happens and it just makes things ten times worse, they fill with water, hit even softer ground deeper down. Go and have a look again at what your SE is expecting in terms of ground conditions. If in doubt ask. Ask your SE if they can be on the end of the phone or just come to site if you get stuck. Yes, I know you probably don't want to pay for an SE visit but at the end of the day it can save you a pile of worry and cash. You only get one real chance of making a good job of this so don't take daft risks. Take time placing any reinforcement mesh.. many ground workers just fling it in.. and you pay for it.. but it is worse than useless if not properly placed.

If you have got the next stages planned in, with contractors lined up, and building regs / warranty people giving the OK to your proposals, you could go ahead. It is not monsoon. It has rained in this country before. You are not made of sugar.

The US dictator will lose interest in Iran quickly - he doesn’t have much of an attention span.

I offer our floor plans, as your house is almost the same size and shape as ours. Context. North is up. Front of house is north facing so at the top of the plans, garden is to the south and West mainly with good views to both. We have an addition of a single storey sun room at the back and a single garage on the east end of the house with a room above it. Things we particularly like. The double aspect kitchen diner as noted before in this thread. That opens to the sun room at the back. The Lounge looks out over the garden to the back / south. The double doors from both main rooms to the entrance hall that when open make it almost one large space. Almost no space wasted with corridors and a simple un cluttered layout. There were some minor changes to the bathroom / en suite at actual build but only minor.

The rear aspect to the garden can be from the lounge and kitchen dining for the garden, and you also can see if people are arriving at your house to the front from the kitchen area, it’s just nicer to be able to do that in a house imo. If you think about it, you spend more time sitting in a lounge looking to the garden, not dining and cooking. you want your lounge on the back, not the front. where you have the WC/Shower is a bit wasted to be honest, not a fan of that. I’d rather just commit to a proper bathroom than mess about with a nothing room with a toilet and 2 doors. Everyone can use the bathroom rather than no one ever. Bathrooms are expensive, make the most of them. so yes, you come in the front door, put your coat in the cupboard, then use the WC. Kitchen on the left, lounge straight on. It just makes sense to me that’s how people use a house.

Better to invest the same amount of cash in defense and medical shares.

indeed. and it is the contractor who would be in very big trouble for not declaring the income. The IR know when annual returns look imbalanced and the VAT computer spots anomalies too. Plus taxes do have a purpose. That customer is probably going through life complaining about government services, and the brown envelope brigade because that is what they would do. 'How much for cash in hand?' Oh just allow a 5% handling charge.

It's funny the cash in hand malarkey. From the other side, it's so common for me to be asked by customers if I'll do the job cash in hand. I never do jobs cash in hand because they're the ones that show up the nature of the customer - they want cheap cash in hand deals but at the same time also want all the regulatory sign off and building regulations notifications is incredible. And they want all the back-up as and when suits them. As a trade, you need your wits about you to choose your customers wisely too!

Lost track of websites visited, videos watched. Glad I asked here

Normally you will leave the battens short of the window opening so the air can flow round. Like this:

100mm is fine, as long as what it's on is not crumbling etc.

Yes, so the paper manuals and guides I used for all my basic training are (no great thermodynamics knowledge needed with these, thankfully 🙂). The underfloor heating design has lots of tables to referencing outputs and floor temps etc. and dovetails in the the CIBSE industry guide for sizing and designing heating system. The low temp guide has lots of easy win nomographs which can save a lot of time for ballpark figures: This links into the above question. As the output of the floor depends on pipe spacing, it seems weird that we can just discount that in design and just not worry about it? Output depends on the balance of several factors, including spacing flow rates and flow temperature all together. The calculation regarding the output of buried pipes is actually quite complex calculation, simplified here in this image: If you have significant transfer across the centre lines, then you're going to have problems with the balance of system output. Here is some images from a much more detailed hydronic books, which illustrate correctly varying the pipe spacing - look for example at where the spacing it closer at certain external parts of the rooms (this is also covered in the ufh design book above but to a much lesser detail: These and the illustration of pipe centre lines are from Modern Hydronic Heating & Cooling by John Siegenthaler. It has a very detailed section of UFH design, but the book costs nearly £100 and it's all in imperial so you need a way of looking up the metric constants etc. for SI unit conversion. HTH

Hi, Was going down the route of Sips build with vaulted truss roof, contacted a few companies and picked a company for the kit that assured me they would build me a nearly passive house and build it in an efficient manor with no hidden extras, they told me in second week in January drawing for BC would take about one week, to cut a long story short nearly eight weeks later no drawings, very poor communication, I found another company and now going down total TF design with same U-values as SIP’s, price is 12k dearer but includes all windows and doors, all walls inside, fully plaster boarded inside, I phoned the first company to speak to the director who I could never get a hold of and spoke to the receptionist to say I had lost confidence in them, surprisingly he phoned me back in five minutes and totally understood my decision and apologised for lack of communication and said he was sorry for the delays and could not find an engineer that could do calculations for the steel work, I told him that I was sorry but if things are going wrong at this stage then I cannot let you continue with my build, I am now really glad I have swapped TF supplier…

All modern traps are "top" or "self" cleaning, which means you don't need access to anything other than the basket and trap that you get to from above.

Dunno if it's in the spirit of the forum to disclose company names? @Buildhub Moderators can delete if required. These are windows from NordVest. Have checked warranty detail. 2 years parts & labour, 5 years glazing & labour; further 5 years glazing but no labour....just shows how variable warranty can be. Perhaps I should have looked into this in more detail when choosing a supplier. But the headline "10 year warranty" seemed comparable with others. Doesn't fill me with joy for the long term. However they have accepted the warranty claim with fairly minimal fuss (a surprise based on previous issues). So new glass is on the way.

Exactly. There are chances and hassles I'll take on for a personal project, whereas for a client I'd accept the norm. I've been challenging the easy norms for decades. It results in better knowledge, the good ideas becoming standard details then improving every project thereafter. The bad ideas rejected and knowing why. Back to the original post. We don't want heat loss from the hot pipe, especially to the cold pipe. I considered the @SimonDproposal for a bit, using the insulated pipes in a duct... if it ever failed they could be pulled out and replaced with uninsulated pipes. This could be a good standard method where there doesn't happen to be 300mm of insulation. But the 2 subbies are now on board my way so it will go alright. I've even found 2 lengths of so-called barrier pipe with the magic layer of coloured plastic... it's just normal pipe. The guidance above is sensible. Building moves and pipe fails? wont happen: each pipe will be continuous so no joints. They can move within the eps. They are 150mm below the screed so won't be screwed into. The ends will be apparent as the pipes will pop up into view. If ever the pipe needed changing, there is tile, screed pir.... not destructive. I know this is ott, but we have this opportunity to exceed expectations. As for the bco... they trust us. We welcome any query. When we adopt novel approaches we explain. If necessary we present it formally for their files. Only my time has been expended and I am foc And your time for which thanks

Such an important bit of advice. Most bolts are overtightened.

I have forwarded the UFH stapler to @Great_scot_selfbuild

Not needed as it refers largely, if not entirely, to fittings. No fittings = common sense can prevail. Probably spent more time typing this than installing 2 pairs of both solutions though, lol. Self-building at it's best (worst?), eg set fire to £500 worth of time solving a £300 problem. Then multiply!!

Yeah, pull the other one. You'll be swearing for a month of Sundays getting it straight and keeping it straight even if it is lay-flat. So you believe the marketing blurb of these but not the technical documentation for MLCP? Well, here you you go. As it's going to be in insulation, the 9mm thickness will be absolutely fine? What diameter would you like sir? 16 Blue and Red https://www.plumbingforless.co.uk/plumbing/unipress-mlcp/unipress-mlcp-pipe/unipress-50mtr-mlcp-16mmx2.0-9mm-red https://www.plumbingforless.co.uk/plumbing/unipress-mlcp/unipress-mlcp-pipe/unipress-50mtr-mlcp-16mmx2.0-9mm-blue 20 Blue and Red https://www.plumbingforless.co.uk/plumbing/unipress-mlcp/unipress-mlcp-pipe/unipress-50mtr-mlpipe-20mmx2.0-9mm-red https://www.plumbingforless.co.uk/plumbing/unipress-mlcp/unipress-mlcp-pipe/unipress-50mtr-mlpipe-20mmx2.0-9mm-blue Oh, and here you go, Wolseley, pipe in pipe Mlcp: https://www.wolseley.co.uk/product/uponor-mlc-insulated-pipe-13mm-25-x-25mm-50mtr-blue/ And it confirms that: This Uponor MLC 13mm, 2.5mm thick pipe-in-pipe is designed for integration into a building structure and can be safely covered with screed. Withdrawn without causing structural damage, this water regs compliant pipe-in-pipe is supplied in 50M lengths. Product features Suitable for hot and cold and heating systems Suitable for recirculation hot water systems PE-X material construction Meets BS EN 13501-1 Complies with water regulations 1999 Any decent plumbers merchant will be able to order some in from one of the multitude of manufacturers out there and the good thing is that it's often cheaper than standard plastic PEX of Polybutylene. But hey ho, go with your barrier pipe...even if the world is moving on.

An update. Mrs BB made up a paste of Bicard of Soda and a little water. Applied it to the offending handles with a finger. The washed off with some warm soapy water. Before: After: (dusty at the top due to work I was doing today)

I think you've just described properties in the opposite of the order most people put them in. Most people will think less about spending huge amounts of money on kitchens and bathrooms, but will then skimp on a heating system, unless it's a flashy column radiator..

Building Regs do tend to be open to interpretation, but what you can lean on and discuss with your BCO if it's a problem is that in accordance with industry practice and guidance (CIBSE Domestic Heating Design Guide) for any new build, a design temperature of 21C should be used throughout the building - because of higher insulation levels and we hope, better airtightness. In this sense, adjacent rooms can be considered as a single zone: 5.21.b

Battery - so only pay 15p max for electric. But air fryer most evenings instead of a big oven (only two of us)

Yes they're crazily low. By my calculation the pressure drop in your longest ufh loop, 95m and flow rate of 2l/m is something like 12.8kPa. And then we have 10m on the 28mm pipework, assuming up to 7kW is just under 3.5kPa. So you are fine.

The bigger dimensions buy you some more space alright.

No time like now. The amount of jobs I start in the ground in the depths of winter is far higher than those which start in summer. It generally pans out ok unless there is a significant seasonal water table. Even that is generally manageable if less than ideal.

It’s not highlighted in that drawing but the GRP angle was resin bolted to the face of the slab. Actually, I don’t think it was resin bolted. I can’t quite remember how it was done, I’ll check the photos when I get home.

They’re more likely to run out of things to fire at ‘the enemy’, at the rate that they’re going through munitions.

Why not run for 15 mins every hour or 30 mins every other hour etc?

it does but if you look at the two details in comparison, they are different. The detail from MBC is spreading the load between EPS & slab. The above detail is compac foam sitting 60% approx. on slab, 40% on insulation. It needs supported full depth and down, not on 100mm of insulation.

It’d be brighter with windows on 3 aspects wouldn’t it?

Worse is cement and concrete. There's a barrow on site with a lot of concrete in it and collapsed against the wheel. It wasn't my lovely barrow fortunately but it seems to be mine now, to get rid of. Subbies will nearly always look after their own stuff better than yours. They will request plant that they wouldn't hire themselves, and better than they need. Then they will let the use, and hire, drift. BUT sometimes the right kit will do in minutes what will take hours without. What do you want, why, and for how long? Then you manage its use and condition.

I used a groundworker recently and he didn't bring any tools. He and his labourer were constantly asking if they could use this and that. So many of tools ended up covered in mud. In the end I did say "do you not have your own tools". It's a conversation that I shouldn't need to have.

Thanks, I see the point now! I'll give it a go Friday when I'm next free

Oh, no, did it go that badly?

If these use the same internals then it's likely the minimum modulation is the same on both. If that's true then there is no benefit for going with the smaller model. Which means with a max heat loss of 2.8kw and a 7kw heatpump you will likely see a lot of cycling which is not great for efficiency. I feel like I'm channelling @JohnMo, surprised he hasn't spoken up yet.

We're still 4, two teenage boys who disappear for an eternity when they have showers! But, with DHW there is actually a detailed calculation method which should be more accurate, but I doubt a lot of designers will spend the time completing those calcs. Now, for a moment I was about to respond on your question about the rethink, but I then wonder whether the industry really is that responsive? It's only taken them 9 years to implement a hybrid version of the 2017 standards....and even then they still haven't ratified the national annexes to the standard, so you can still, according to MCS just use BS EN 1283-1:2017 for your heat loss calcs, for example, and ignore the new CIBSE guide because MCS only require calcs to be to that standard. So still a bit of a mess, but a step in the right direction. It'll be interesting to see what the fallout will be because if I now update a design just completed for a customer, the airing cupboard is not going to fit a 400l cylinder!

Most self builders on the forum had no issues with their BCO and MVHR. My BCO rejected my first self certifying report as the Anemometer had no proof of being calibrated, (used the Buildhub anemometer) I hired this :https://www.inlec.com/testo-417-vane-anemometer-with-flow-hoods Wrote a commissioning report with photos and had to be a little creative with the figures as our MVHR is slightly undersize for the volume of the house. Works perfectly though.

Sorry, I can't help with this, but I must congratulate you on moving in, having completed your build so quickly. You're an inspiration to us all. & thanks for documenting your progress on here too - it's a real help to those of us who are not there yet.

Alternatively. Buy some cheap/dummy thermostats, stick them all over the place and bin them when your house is signed off 😃 ~~~ Our place is a bit smaller than yours and we only have one thermostat downstairs. Nothing was mentioned.

The 150, 200, 250 & 400mb or whatever settings in the WB are CP (Constant Pressure)settings. At the 400mb (4.0M) setting the pump will be running at 100% to just about achieve 20.9LPM at 4.0M (residual head) at the rads, if TRVs reduced the flowrate to say 10.0LPM then the head will remain the same 4.0M but the pump speed will fall to 81%, if the TRVs throttled down the flow to 5.0LPM then the pump speed will fall to 75% but the head remains the same at 4.0bar. If the boiler pump was like the 8M Wilo Yonos Pico set to 4.8M in its PP mode then that will achieve 20.9LPM at 4.0M, if the TRVs throttle down the flow, the pump speed will reduce to give 10.0LPM at 3.0M & 5.0LPM at 2.7M but the TRVvs will be opened a bit further, obviously if the PP setting is lower then the heads at 10LPM & 5LPM will be lower still and the TRVs will open still further. This boiler has, I think, a variable speed setting, 0?, I think it aims to get the flow/return dT to ~ 20C, the rad output then for any given flow temp, outside temp & room temp will start reducing, the boiler output will then reduce to match this. The latest Vaillant boiler has this, where the dT can be set between 10C & 20C but doesn’t seem to work very well on at least on one user's boiler that I’m aware of.

We self-installed a 5 kW Panasonic Aquarea in 2015. Our electrician did the wiring (very simple) and the plumber took care of the plumbing from where it entered the house. We probably paid £400 all up for the installation, maybe less. I did the pipework from the plant room, through the underslab insulation, and plumbed it into the unit. As to why we went with a heat pump: Despite there being gas on the road and the bungalow we were replacing being built in the 1950s, there was no gas to the property. It would have cost us time, money, and disruption to install gas. We wanted to avoid paying two lots of standing charges. We'd used an induction hob at a friend's place and wanted one of those instead of a gas cooker. We were going for PassivHaus class insulation and airtightness, so we knew that we wouldn't need a massive heat source to heat it. The idea of a low-and-slow option seemed more compatible with the house's thermal characteristics. We wanted the option of cooling. Having lived with it for about 8 years (we didn't enable it for the first couple of years), this is probably one of the best reasons to choose ASHP in a well-insulated house with UFH, imo. We (well, I!) wanted some sort of home automation, and I felt that an ASHP offered more interesting control options than a boiler. We haven't actually integrated the ASHP in the way I'd thought we might (the modbus module for the ASHP was too expensive to justify), so this point was somewhat moot in the end. We installed a lot of solar (8.5 kWp) and I thought we'd be able to at least partly power the ASHP with excess solar. With the benefit of hindsight, I'm not sure this was a great argument. I'm genuinely unsure how often we generate excess energy at a time when the house needs heating. In the shoulder months we often don't need heat, and in winter when heat's required, we often generate very little solar, let alone excess solar. I don't remember whether I considered E7, E10, or any other time of use tariffs at the time we made the decision to go with an ASHP, but cheap overnight rates have since become of the strongest reasons for using an ASHP imo. For example, I have our system set to prioritise heating during the 6 hour cheap window with have with Intelligent Octopus Go. I allow a little bit of overheating during that period, and allow things to cool down a little more during the expensive period before turning on the heating. There are sometimes periods of several days where the heating is only on during the cheap period, which is quite satisfying to see given it's about a quarter of the price than the peak rate. The main concern I had was DHW recharge time. That hasn't turned out to be a massive issue, except when our younger one - Mr three-hour-shower-of-power - is home for the holidays. Upon reflection, I'd have gone for a larger tank than the 250 L one we installed. That would have allowed me to lower the DHW temp even further, while ensuring ample hot water. I don't know how repairable boilers are, but I get the sense that ASHPs could have a very long life, at least while parts are still available for any given model. How repairable any particular issue is depends on the failure mode. About three years after we installed the unit, either the control board or the pump failed. Apparently both are replaced at the same time, because it isn't possible to tell why one or the other failed, and one of them failing can bring the other one down with it. Sounded like bollocks to me, but I did a bit of research at the time and this seemed to be a common view. I don't recall what that cost us, because it was tied up with some other work, but certainly it was several hundred quid. I think the pump alone might have been £400, which sounded like an utter rort for a smallish pump, but I wasn't able to find a cheaper equivalent. It's since continued running without issue for a further 7 years. If something catastrophic happened and the whole unit needed replacing, I'd just go and buy a new one for £2-3k and install it myself, reusing the existing wiring and plumbing. The units themselves aren't that expensive, even for decent brands. For example, the current equivalent of the model we installed is about £2700.

If you need to cover 100mm then you’d be looking at minimum 2 runs of 60mm tape to do that, I’d go 3 for robustness and to give a decent overlap. You can buy thicker tapes, but you just end up trying to buy the right thickness tape for xyz locations and as a contractor it just isn’t economical. Wider tape costs more than narrow tape so 🤷‍♂️. Yes, self builders are mostly all loonies, so I am making plenty of adjustments lol. Sand and cement doesn’t really parge well, unless you mix a bit of SBR in and get the consistency perfect each mix, then it still goes quite granular as you spears it out and the masonry almost immediately sucks the moisture straight out of it. Then it’s like making thin sandcastles on vertical surfaces, give it a go if you wish, which is where you will thank me. I accept all major brands of beer / IPA. Remind me are you using AeroBarrier or just tape / foam / parge / liquid AVCL? Are you saying you’re going to spray the whole house interior with liquid AVCL??