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I'm actually not sure where the best place is to post this but as it's primarily about heat pump system design, I'll put it here. @marshian and @mads ,and maybe @MikeSharp01? you've expressed your interest so mentioning you here too. I hope the admins don't mind me putting this up here, but maybe if it is found to be useful, could be pinned to help so many of the people who come here struggling with poor heat loss calcs and designs and want to complete their own. I've finally deployed the tool I've been working on for initial public use. It's available free and open source, so repository on GitHub if anyone wants to host locally. It's currently in a bit of a test mode so I can get some feedback and bug reports to refine it and add further important functions. Just bear in mind I've been developing this myself along with everything else in life and it's been quite a major piece of work since last summer. It is now based on the CIBSE 2026 Domestic Heating Design Guide implementation of BS EN 12831:2017 and BS EN12831:2017 so complies with MCS design requirements. I have been using this tool for MCS heat pump projects in house that I'm doing. It's at https://openheatloss.com Important user notes: At the moment when you arrive, you can complete a whole project anonymously without logging in but this persists only for 48 hours or until you close the browser. The save a project, just register using name and email, nothing else. If you want to remain largely anonymous, you can just add the post code prefix to the installation address to set outdoor design temperature and Typical reference temperature. No need to put in loads of personal information. The workflow design is to work you way from left to right across the app tabs. Current limitations: I have not populated the database with standard wall build-ups and U-values. If you're a self-builder or doing major diy hopefully you'll have this info already for your project, otherwise you'll need to look it up manually. There is, however, a comprehensive floor u-value calculator and a simplified one in the room elements input too, so these can be calculated for you. Same thing with radiators - no standard sizes or outputs in a global database yet. I will do a scrape at some point. All outputs entered should be the Delta T 50 catalogue values and if you want system volume calcs, also input the radiator water volume. The UFH sizing calculates volume automatically based on your set pipe diameter, spacing and room area. Text based design - I've tried some of the design tools that are trying to be like cad design software, so you've got do draw your project. Having used cad software, I didn't warm to any of them because they're not proper cad software but in house bespoke design. As I also found out they have limitations so you have to fudge some shapes - roofs in particular. Text based means you can input elements more flexibly according to your needs. Well, I hope so anyway. What you will find different if you've used other tools, although I'm sure they'll either be doing it already or soon, is that the tool provides 2 different heat load figures. is for the heat generator which calculates the whole house fabric and normal ventilation includes a full fabric air infiltration calculation and is usually higher than the generator load To explain this, the new heat loss calculation methods according to BS EN 12931:2017 and specifically those implemented in CIBSE 2026, with wind load under certain conditions, parts of the building and rooms may require higher heat outputs, whilst other parts may need less. This 'total' value comes to a higher result than the generator. In my own test projects that I've run through the new software, I can attest to this working quite well. For example, in one design and installation project of mine, one particular room in the house was designed for 23C but over the winter, whilst never cold, the room never managed more than 21C. I had thought it was a balancing issue, but no. When I ran this project through the new software it predicted that I would need larger radiators in this particular room, base on the new ventilation infiltration calculation, so that is what I will be installing before next winter. Anyway, please have a go and let me know what you think, and ask any questions you have here, or email me at the tool - heatloss@openheatloss.com Does anyone need a user guide to the design workflow and inputs? Let me know..

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The thing is that snagging stuff is mostly at the finishing stage, because that is what is visible. It begs the question of what 'snags' might exist in foundations, drains, structure, electrical cabling etc. New build estates can look good when newly built, go back 10 years later and you can find rainwater stains all down the render, paint/finishing peeling off window frames, rotten fences, cracked kerbs etc. Suddenly it doesn't look like a place you would want to live. As the generations pass, general knowledge and basic skills seem to erode. Most used to have some DIY manuals and knew how to change a plug, a tap washer, put up some shelves, change their car oil, mix cement, and keep house and home together. Usually learned helping out dad as a kid. These days a lot of that seems to have all but disappeared. Contributed to by youngsters in generation rent that have to call the landlord and not fix it themselves.

You are comparing apples to strawberries, they both do entirely different things. If I had to choose where to spend my £7k, it would be MVHR every time. The air quality and comfort you get from one is very hard to describe and quantify, but very real. Besides, grants are coming in for A2A HP's soon so you might be able to get one retrofitted later under that if you want cooling/heating from an AC unit

Hi all, thought I’d share our garden room build now that it’s finished. It was a proper self-build from start to finish, including the design, and we put a lot of time into researching the best way to approach it before we began. We tried to follow good building practice wherever possible, while still keeping it realistic for a garden room build. I’ve attached a few pictures in case they’re useful to anyone planning something similar. We also filmed the whole process and put it together as a YouTube playlist, documenting the reasoning behind the different decisions we made along the way. We found that especially helpful when researching, as there’s a lot of advice out there and not all of it is equally useful. It’s been a really rewarding project, and I’m proud of what we’ve managed to build as a DIYer with a bit of planning and the right approach. I’m looking forward to using it as an office for many years to come. Would be great to hear what others have done too.

Better if you can send a dimensioned copy of the floor plans and elevations together with all the U-values for the elements - windows, doors, internal/external walls, floor, ceiling, roof, etc. - and the design air permeability or test results in q50 and any MVHR specs. Then privately share your postcode. If I have all these details I can run a fully BS EN12831 heat loss calc to current MCS standards which not only provides a heat generator loading, but also the room loading based on calculated air permeability. I can then also provide initial figures for any underfloor heating design and requirements together with flow temps & floor surface temps assuming that's what you're having. I have a tool that will soon be available free for self-builders, but I'm currently working through final bug fixing and hosting, so it's going to take a few weeks until it's online. Please feel welcome to send me a PM.

This published Thursday and surprisingly the only mention I've seen of it. Not surprising. Maybe old news regurgitated.

I’m a bricklayer. Just had planning approved for south Scotland. Was told rigid boards (PIR) is the standard with 50mm air gap. I sent a email over to building control about having Dritherm 32 fulfill along with the BAA certification. They replied saying I can go ahead with it as long as installed to manufacturers standards. There was no way I would do PIR. Even on my own build taking all the time in the world it would be a nightmare to install. Looks great on a drawing but it just don’t happen in real life and when the bricklayers not getting paid much to take the time you end up with a right mess as shown in photos above. It repels moisture too so won’t get through the cavity, even in exposed locations like mine.

The "render onto foam insulation that is screwed to the wall" method has some risks. In theory a well done ewi solution should protect the building from thr elements and preserve the wall by keeping it warmer and drier. The aesthetic will almost certainly change if you start with brick or stone. There ain't really a way to mimic that - and I'm not sure we should try. Lean into the fact our buikdings are changing to adapt to new circumstances. It has always been so. Structures are extended, modified, uses change, windows are added and subtracted, uses change again etc. Many of our houses were never built with electrical wiring or central heating. A good few didn't have plumbing and some didn't even have indoor toilets. These new technologies were added as circumstance changed. The addition of ewi is just another chapter.

For the lol's or alternatively why I DIY rather than pay people to do things I had the drive brick-weaved about many years ago - but in the last few years the manhole cover seems to be rising out of the drive Of course that's pretty unusual and I suspected that it was actually the area around it was getting lower but wondered how that was happening So I removed a load of blocks and then the manhole cover and found my issue - the frame was sitting on what remained of the original mortar a very uneven mess - bedded down on 4 blobs of silicone!!! FFS So there was my smoking gun - the sand was being washed into the manhole when we had a downpour and there wasn't a car on top of it. So I got the concrete grinder out and leveled the top off Bedded it down on some mortar and threw the sand back in - a few sting lines to get the level and the pile of blocks can go back in All done

It's not the M1, and will be strong enough. Block paving is flexible so you won't get cracking even if it moves a bit over decades. A whacker is plenty. Do drive over it many times. If it's going to compact , then do it now and the sand will level it off. And now stop worrying.

Yes sadly we have been closing our refineries because they cause too much pollution. Instead we export crude oil and import refined fuel shifting the pollution to another country so we look good. But lousy for energy security, loss of employment, and of course globally it makes no difference to pollution. We just kid ourselves closing our heavy industry saves the planet.

If you've got an electrician, why aren't they doing the necessary calculations? You have to consider voltage drop over the distances you mention, as well as the route the cable will take and whether any of that route is insulated. Some induction hobs are in the 11kW range. If your oven uses pyrolytic cleaning, and it's a double oven, even 6mm2 may not be enough. At the extreme, an 11kW induction hob at the end of a 25m run of cable enclosed in insulation could need a 25mm2 cable and a 50A RCBO or equivalent. Can't stress strongly enough that your electrician should be looking at these sorts of considerations and advising you on the appropriate cable sizes. Like @Russell griffiths we have 10mm2 to an induction hob, 6mm2 to a pyrolytic single oven, and 6mm2 to a combination pyrolytic oven/microwave which also serves a warming drawer, all on radial circuits with their own RCBOs.

Easy folks! There is the old saying, "if you've nothing good (or helpful / productive) to say, then saying nothing is best". If we can't offer support then let's keep schtum, please. On the flip-side, if anyone feels like they've been singled out or spoken to in a manner that's offended, then please use the REPORT function and the mods will review this and respond accordingly.

As a literal self builder everything delays us, but we continue to slog away. There is a field where the footpath is going past our build as the farmer won't clear the proper one. But, you know you are progressing when the church people on the palm Sunday walk all commented on how much we've done. Since my last update last summer (remember that - heat) when it looked like this. It now looks like this We had a pretty major disaster last Autumn when a 70 mph storm came right over the field and a wall came tumbling down. For context that's the wall by HID and dog. To say that was a low point is a huge understatement. Comments over the dinner table included knocking everything down and reinstating the stables. The corner was left but we just knocked that down as well and when it was rebuilt then we've only gone up to 5 blocks so it's not such a wind target. Obviously, in hindsight we shouldn't have built one wall so high with no support and we are now going up one layer at a time all round. This disaster also cost us lots in money as the 'wall' is now on the rubbish heap along with the lintels. I've not got any photos after it fell as I was just too peed off. We also lost another month because the BCO wanted some technical details of the slab confirmed by the SE as he was concerned that we didn't have the right grade of mesh and it turns out that this was a verbal discussion and I couldn't find anything written down. It turned out fine, but it took weeks for the SE to get around to confirming this. It was only when I threatened to go to his office to discuss that they suddenly arrived. One corner of the site (not yet touched) is clay, everything else is sand and the SE had originally specced for all clay when the BCO said not necessary. The SE came to site and met with the BCO, but it was all a conversation with no official documentation. To replace the look of the barn we have a sloping flat roof and this middle wall is going to hold the joists for each side. These are 140 wide rather than 100. We are looking forward to having the temp window and internal door frames in place soon as that will really start to look like a house. We reckon that at our usual rate of progress that the walls will be up by end Sept. As we want to put the whole roof on at the same time we are going to put up temp joists to ensure that all walls are held together. Then we have a lot more concrete to break and the clay area to consider. Being a hands on builder can be satisfying, but it can also be very stressful and slow. Back again at some point in the future with another update.

This is a good example of why we need a bit of nuance in the debate. You can quite truthfully say that China are building a large number of new coal power stations every year. And if it suits your agenda, that's the end of the sentence. The bigger picture is that these plants are in part replacing older, less efficient ones, and are acting as backup to an increasingly renewables dependent grid. So that China's emissions are actually falling. Good luck finding that level of analysis in the Daily Mail or GB News.

All the talk is about banning social media for under 16, just ban it all together. So much miss information told as a truth, and then the algorithm just points you at similar rubbish. People that don't have science background just lap it up. Sat next to guy on the train he was telling me that people are daft having solar especially in Scotland, I told him how much I had exported so far in March, he was was quite shocked. Also told him what I paid for it as a self install, he expected tens of thousands, not the couple I actually paid.

Drill a dozen 6mm holes and pump it full of "PIR in a can", eg Illbruck foam <20 mins per window, job done

Yesterday we moved into our place, started in 2018 still not 100% finished in 2026, I estimated it would take me 2 years, 🤣🤣 thanks for all the advice from fellow buildhubbers. What we bought, what we have now.

'To comply with the rules' is an answer but its not THE answer. Why is it a rule? I think it is reasonable to require installation of the cabling to a point on an outside wall. In contrast it is nonsense to mandate that i spend a grand of my hard earned for the potential benefit of someone else.

I don’t go to my mates house and ask for diesel for the return journey. why would I let a visitor plug their car in. im baffled by these ludicrous regs.

Decided to buy the materials I need to finish the direct surround of my house before Diesel shortages and goodness knows what else takes hold! 50+m2 of paving blocks, 3 tons of paving grit and a full load of type 2 MOT to spread around the house next month!! I plan to get bound resin for the driveway, either do it myself or pay someone (£150 per square meter though and 50 m2 so 7.5K and thats with me doing all the edging and subbase prep!!). Still there's a couple of wheelbarrows in the materials above to do in the meantime and I did the driveway in my old house next door (fully paved) and it's stood up well. Plan on having a step up to the front door but a ramp off to the right as an alternate path. Have been working upstairs getting things finished. Currently have the stairwell, landing and office room completed and kitted out. Just starting the Master bedroom this week. Then it's off to the outside! I bought a pull out sofa bed, extra computer desk and some IKEA PAX wardrobes for the office room. There wasn't space for 4 Ikea units (500m wide each) so I put in 400mm wide shelving instead - I'll paint at some point. I forgot to level the sides of the double wardrobe before tacking on the back so while the sides are parallel, it's more like a parallelogram and one door is offline. Oh well!! That'll teach me to measure twice!! I'm gluing the bamboo floor upstairs also and Iove the look of it. I can now move into it as a full time office and save the space in my bedroom for the first time ever in nearly 30 years (i.e. no computer in my bedroom anymore!). the two skylights at the top of the stairwell work well. I forgot to clean the upper window and take off the Velux protective tape before taking down the temporary platform and finish the sides. I won't tell you what I did with a ladder to fix this on all fours and ended up heading back to the Chiropractor the next day!! The Master bedroom is a bit tighter but I measured it and think I have a bit of room to play around with 2.85m x 3.5m so a double bed and 500mm lockers either side still gives me a meter on one side or the other to add a dresser or something like that, fitted wardrobes over and around the bed and another at the end of the bed. How to fit a locker into an IKEA system? You can build in space with the PLATSA - I did a free design session with an IKEA rep who showed me how. I'll have to move the plug sockets up or they'll get buried but should be ok otherwise. I plan to fit a table above where the soil pipe boxing protrudes. If you spotted a hole in the wall above the light socket, the door lining screw pierced the electrical wire at that location and all the lights upstairs went out!! Wago repair done. Electrician is out later this week so will have a word!! Energy usage (last 2 months) so far is 11pm-8am 3562 kWh, 5pm-7pm 71 kWh and daytime 316 kWh. I've been fine tuning my usage with the SigEnergy system and tried using AI for a few weeks but it kept taking from the grid during peak times which was very annoying even when being told not to so I went back to manual and fixed time schedules so that's helped a bit. I hope to get peak to 0 if possible. My overall usage is up but my bill is €60 down from the last one two months ago which is from PV Export, the one thing the AI system was good at! I'll have to have a talk with it at some point! Each export unit equates to 1/2 a peak unit that should have been avoided!! Ah, technology!! I just figured out today how to send excess PV to my car when it's plugged in. I had Givenergy in my old house which went into Administration this week, glad I'm not with them anymore! I finally got the glazing for the internal window installed. It's double glazed but with a large airgap for sound proofing. I did considered fire rating it but the price would have been crazy. It's comprised of: 6mm Toughened x 20mm black spacer x 6.4 Laminate for safety. The seat worked out well, just need a few cushions!! My Sigenergy Gateway is being upgraded to 100A from 63A this week. I have an uprated mains supply but it wasn't picked up by the Solar supplier - unlikely I'll draw that much but still nice to have the extra room in Amps if I ever needed it! Unexpected but hope all goes well! Anyway, that's it for now, lots of joint filling on the Fermacell to do this week and sanding....!

This is ours.. Bought fish, two times now. Just Goldfish, the second batch got about 200mm long last year , then one day the otter cam and that was that. We have had ducklings the last few years raised here. Pretty much there's always a Heron comes by, ducks usually there had geese. My son loves it in the summer, wife goes dipping in the winter ( we all done it Xmas day had to break the ice) . It's just a hole dug with diggers inflow from run off and outflow to the burn. The Clay keeps the level from not changing. It's great.

First heat pump name plate ratings are meaningless. They all take a different datum point for the rating. Vaillant tend to use a low ambient. Worst thing you can do for efficiency is oversize you heat oump. On the design day and they don't happen often you can always flick on the immersion, but doubt you will need too.

I am installing 5A lighting sockets in the living room and a bedroom of my new build. I intend to use plenty of "smart" lighting. But I want everything "smart" to be fully removable for a future buyer (or renter) so am designing & building the house with a good non-smart lighting system first. (At switches, I am installing the deepest back boxes anticipating future "smart" things.)

Following up on Russell's post, I've used Tikkurila Anti-Reflex throughout my home on the ceilings and would never use anything else. Excellent paint. Hides many issues. Not sure Farrow & Ball have premium paint, but they definitely have premium marketing... 😉

Wrong paint I’m afraid. johnstones perfect matt or tikurila. I’ve never used the Tikurila, but the johnstones is good stuff. I’ve got some serious ceilings with big windows and loads of natural light. The Johnstones hides a lot of stuff.

Irrelevant. Even if there were zero reduction in CO2 emissions, my position is unchanged. Even if arguments that drilling won't be practical or profitable are correct, then either: Oil companies won't drill even if granted licences, in which case the argument is moot. Or they'll drill, lose money, and presumably stop drilling when it becomes clear they made a mistake. In both cases, the end result is drilling doesn't continue. I don't actually have strong beliefs either way, but I do believe that non-experts (including governments) shouldn't be involved in decisions about whether something is practical or profitable for a company. There are, or course, plenty of other factors that governments should weigh in on, such as safety regs, environment, tax, etc.

The mechanicals will always need replacing, that’s just acceptable as things that move wear out. The backbone (such as UFH pipes etc cast into screed or slabs, plus MVHR ducting set into the frame and fabric of the dwelling) is where you should focus concerns of “ultimate longevity”. Most build systems have to withstand 50-60 years of occupancy and ‘use’ but that’s mostly for sub and superstructure; the pretty stuff can be changed retrospectively, and one can assume a full cosmetic makeover (x2) in a 50 year span, to allow for end of life or keeping up with modern taste / style etc.

Evidently not an original idea, but build to the Passivhaus standard (or close to it as feasible) and minimise the need for high-tech solutions. Though I'd now evaluate summer overheating against forecast climate data for the 2070s, now that it's available in granular detail for the UK. As for long term maintenance costs & durability, the 25-year evaluation of the original Darmstadt passive houses (occupied since October 1991), available here, is interesting. TLDR: Heating requirement: average for the 4 homes remains stable at 8.4 kWh/m²/year (compared to the 2016 German average of 138 kWh/m²/year) Glazing: gas losses from the triple low-e glazing units so low that these can be used for at least two additional decades Airtightness: after replacing the seals of the opening lights, airtightness returned to the as-built value (0.21, from 0.26 pre-replacement) MVHR: no significant contamination despite never having been cleaned, expected to last >50 years apart from filter changes and fan replacement (1 of the 4 MVHR units had 2 fans replaced in 2002 for about €500; all others were still original)

Ive got a pair of Kress mowers bought in last years grand 70% off sale. Between them they cover circa 2.5 acres, 2/3rds of that is a fairly rough field. Hardware is great, customer support, great. They updated the app last month. Now utter garbage. Was fine before. Hopefully they will sort out the app. Their business model is 100% via dealers. So if you are an IT numpty like me, thats a result. But comes at a cost V cheap chinese ones, where you are the support. Pic here of the first cut of the field. The main reason for getting them, is its simply too waterlogged to get and machinery on it until late may. 2 years ago it was still so soft in August i buried the tractor up to its axles in mud! The mowers are quite happy as they are light.

After the debacle of the last builder, who just couldn’t admit his work was rough, I decided to get https://www.tmcoatesjcbplanthire.co.uk/ back in to dig down the oversite ready for the next brickie that we have managed to get on board. Tim is an absolute legend and goes above and beyond when it comes to excavation tasks! here is a picture of our site (I’ve demolished the abomination left by the last incumbent)

If all the houses get sold, then they are too cheap. Not that often I agree with @Roger440, but he is spot on when comparing house and car quality. It is why kit car manufacturers don't make very good products. The components parts may reach a set quality level, just as they do in the housing industry. Then then get put together by morons. It is often quoted that you cannot have speed, quality and cheapness. You can, it is what production engineering does every hour of every day.

You'd say an induction hob with multiple rings doesn't have multiple points of utilisation? It's a moot point really though. I have 25 years experience in this exact area, doing this sort of thing every day of the week. If someone wants to ignore my opinion, and that of the IET On Site Guide, then I don't think I'll even attempt to change their mind.

Not true. See below in Table A2 of the On Site Guide. Yes, this is only a 'guide', but as above, I've been doing this for 25 years and have probably fitted thousands of cookers and following this formula has never yet caused me a problem and often saves my customers lots of unnecessary cost and disruption in an existing property. Correct Yes, which has a large influence on cable size. The others being installation methods, correction factors and volt drop usually. It's fairly unusual for 6mm2 not to be big enough in a domestic property. I am an electrician 😉 Diversity - On Site Guide - 18th Ed BS7671.pdf

I don't want to hijack this thread, but here are some screen shots. The app will be open source with repo on GitHub of course. Problem is I keep on thinking about additional functionality and adding that after customer questions so I need to be more disciplined and release a version 1 I can then build on rather than continuously develop!

Couldn’t agree more. I’ve yet to find an element of this project where doing some due diligence and checking of my own hasn’t thrown up very valuable questions or even identified glaring errors. I equate it to doing a QA ‘dip check’ and then finding I quickly need to ramp up to a 100% check 😭

We have just signed up for Starlink, which seems to be on special offer this month in our area, for £25 a month for six months then £35 a month. That is for the cheapest level which is 100mbps which is 10 times our current 10mbps on copper line. If it all works out ok we'll scrap the Openreach line all together.

IMO, do NOT use this person for anymore work, particularly above ground. I had someone do some work for me recently who I can heartily recommend, based RG6 4 postcode area (S Reading) PM me for details

They also import the coal - not energy self sufficient. We don't have much coal as proven reserves, so you are saying the policy is build coal powered power stations that rely on imported coal. There is zero business case for that sort of project. Why would anyone spend there money on that. A power station that has been shutdown and not had preservation maintenance completed will be good for scrap only. All the rotating equipment (turbines generators, pumps, fans) will have bowed shafts, the bearings and seals will be no use. Think the l'm for coal lobby, live in a make believe world, that doesn't exist. I will bow out now.

To summarise: We should want to reduce dependence on imported fuels. Given our current situation and available resources by far the quickest, cheapest and easiest way to do this is to build more solar, wind and battery storage. Everything else is more expensive and slower.

no idea about plant watering but we have sucessfully installed 15000litre underground potable tank with pump controlled by pressure switch/pressure tank. filters before tank. Once in house water goes through 3 stage filter then UV - feeds into hot water tank (set at 55° - which as far as i know will kill anything) /hot taps/shower and cold taps/washing machine/dishwasher/toilet cistern. Water not completely clear with tanins still present but not bad at all. Think this will improve however over time as found about 6 weeks ago groundworker was incapable of following clear instructions regarding tank overflow - I've done a temporary fix - another job on list for summer! Once we have built kitchen we'll have reverse osmosis supply to kitchen sink and bathroom basin. Once all in we'll get RO sample tested (and UV only for interest). I'll be astonished if any issues but better to be safe before drinking. If calcs right reckon a full tank will last at least 50 days without rain. Might add another tank for additional storage and/or a connection (dryer season only) from a second roof not currently utilised, and we do have back up supply if really needed. I found the numerous 'uk rainwater harvesting companies' pretty useless and arrogant - most are just ticking boxes / playing at it imo. and found lots of info on Australian/US sites - they are way ahead - and worked out for myself along with significant assistance from pumpexpress.co.uk who suggested schemes and products - which we bought from them. definitely worth talking to. The potable tank from elsewhere - shop around and be careful.

I didnt build this. Fed off barn roof. Clay lined. 4m deep. Sadly, was entirely surrounded by rushes. Slowly eliminating and replacing with other stuff. But its big, so years of work

So no acid rain, the most polluting form of electric, yes it great. By the time you opened the coal mines to feed one coal power station and build the power station, you could have built 3x the capacity in wind - Scotland did.

We paid roughly £6k for our design drawings + planning application management. We had some other, cheaper quotes from architects who seemed very nice. We ultimately picked a more expensive one purely because he was insanely responsive and proactive with all his ideas. Absolutely zero regrets so far; he's been incredible. The responsiveness alone is worth its weight in gold. So sick of people just not replying or taking eons to get their stuff together.

Ask @flanagaj what he paid, then pay more than that. Then you won't have to come here asking questions about basic design stuff, that should be in the drawings already.

Food for thought: Another way of approaching this is to ask. What would it cost you to get a washing machine repair Engineer? Say £50- 60 quid an hour? Ok they have a "down time" that they don't get paid for as they may be at your house for an hour then have to drive to the next job, but someone has to pay for that. Now typical rates for a structural engineer working under the IR35 scheme in the UK are about £350 to £500 a day, equates to £45 - £70 an hour as they get paid for a full 8 hour day. Much depends on experience! Go to a self employed SE/ Architectural Designer like me who has no employees then the rates are about the same except that I have overheads. These are primarily my software, my PI insurance and admin costs. Admin / business generating costs. Admin is admin, I pay an accountant, have to keep records, a secure data base etc.. but quite a lot of time is spent generating business that a contractor under IR 35 does not have to do. Turning now to say a small Architect practice with four or five employees that are innovative, expanding and so on. The overheads shoot up, often dramatically. How long is the string? Well it has no end. This is a summary for sake of conversation. It used to be in the old days that say Architect's, Engineers, Surveyors got a percentage of the build cost. But as the market got more competetive and folk like say MBC timber frame (the list is endless) came along and offered a design service then the main designers.. like Architect's, SE's just shifted part of the design work onto them. Now all that worked ok for a bit.. but now it's got to the stage where the lack of coordination is really causing problems. This is not helped by TV programmes ect that often suggest you can pick builder and design sevices like something off a barber shop menu and it will all be ok at the end of the day. My take: It's vitally important to understand what you designer is offering. Not just in terms of say doing a few drawings but also their understanding of how the design process works practically and how you go about communication to and finding the right builder. . I find that often once I explain this "added value" then many are happy to pay for a service that includes much more than drawings and some structural calculations. In the round once you become a competant designer then the rest is down to communication.. which is a skill in itself. 2% of a build cost for an Architect Take a house extension at 100k.. you won't get much for your two thousand pounds. take a new build at 300k with all the work that goes along with that, dealing with the roads, environments, water board.. all that stuff all for 6.0k. Just maybe but I would not do it as I know I would have to cut corners.. which will come back to bite eveyone. Quite often these days I break down my quotes / estimates into how long I'll spend on each element of the design. I'll maybe say.. two days to survey the site, at £xx amount per hour and so on. I find Clients embrace my transparency. It is very rare that they come back and say my hourly or daily rate is too high. In the round I don't think applying a percentage fee cost works anymore.. you have to be much more streetwise.

Which is why it hurts when good advice is totally ignored.

Go for a twin wall Larsen truss or I-beam, and lose all this unnecessary complication. PIR is a complete and total PITA to cut and fit (properly) so just go for blowing cellulose and gain the benefits of a one man insulation process (roof and walls) and also the hugely improved sound-deadening that you lose with PIR. Your initial proposal is hugely over complicated, sorry. KISS wins every time, and will get you to PH targets quickly and simply, with far less to go wrong. The biggest issue will be getting all these layers, materials, installers to do their work meticulously, which most either can’t or don’t.