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Hi all. Eveyone get a like here. DRM, I like the simplicity of your model and saw your post popping up a few days ago. I've put a few numbers to everyone's suggestions regarding beam depths as a conservative first guess and made a few conservative assumptions (please forgive the typos / grammer as I'm off duty): 1/ You are probably going to put a lot of glass surrounding the courtyard bit and maybe a fair bit along the outside walls. All this means that we need to control deflections so we don't cause glazing problems and if we control the deflections usually the steels and connections will also be fine when we check that it won't fall down or blow over in the wind. 2/ Slab thickness. Concrete slabs are heavy things. Let's run with your slab thickness of 200mm for now. As others have said there are other solutions that may be more economic, provide more service space etc. In the round we will end up with a similar roof weight or a bit less. Budget on the really simple stupid for now and then we refine. It gives the Architect (maybe you) more room to be creative if they know the "worst case" at the conceptual stage. 3/ I'm also going to treat all your roof slabs as spanning in one direction rather than two. One direction span (not the pop group) means that you could use a structural B reinforcing mesh. Main bars in the span direction are thicker, the transverse bars control cracking of the slab and a few other things. We can make slabs thinner later if we make them span in two directions.. but we need to balance the cost / knock on effects if we do this... there is no free lunch in this self build world. 4/ I'm going to treat all the beams as simple supported and see what the later results are. When a beam is continuous over say a central column this support can attract a lot more load due to the beam continuity and that can impact on what happens at the bottom so you end up putting more load down the internal columns (can be up to as much as 40%) and foundation pads. Let's go simple stupid for now and see what happens. anyway very long beams are a hassle as you may need special transport.. and that often costs a lot..and they are heavy.. Always look at the cost in the round of steels.. too heavy.. too long and the cost to get them on site and handle can out weigh any clever SE savings. Also pick steels that everyone stocks off the shelf. 5/ I'm going to rationalise all the steel sizes so we can later see if we can get the best out of the stock lengths easily available. It also simplifies the connection design.. many other things that will drive the build cost down. Be aware that when you have steel beams with thinner webs and flanges it can really drive up the fabrication cost and these beams are not a stock item. Don't try and be clever at this stage loking for the lightest weight of steel as it will trip you up later. 6/ There are load of other things but let's do some sums. I'll work from the top roof covering down. Remember I'm sizing conceptually based on deflections, not strength design. I'm going to split up the loads into two components / calculations: The first are how much the beams etc will bend by when say it snows or folk are working on the roof and you introduce say pv panels.... call this the imposed or live load. The second is to see just how much the beams will bend by when all the self weight of the structure and the live load is applied. Lets look at some loadings you could have on the roof if you say live in England / Northern Ireland and benign parts of Scotland, Wales. I'm not going to touch on wind loads (that push the building sideways) as that is for another day. For all I'm going to work in kilo Newtons (kN) as units. 1.0 kN ~ 100kg to give you a flavour of what things weigh. Live loads on the roof prescribed by the design codes: Say typical snow load in England 0.45 kN/m^2 ( kilo Newtons per square metre of roof when looking on plan, straight down) Roof access load for maintenance 0.6 kN/m^2, in the design codes. The access load is greater than the snow load so I'm not going to consider snow load any more, particularly as the roof is flat and I'm assuming that there are not any higher buildings nearby that could dump snow on the roof. Pv panels.. say you have panels but want to put them on a frame to get the aspect right for best preformance 0.25 kN/m^2 Total live load = 0.6 + 0.25 = just say 0.75 kN/m^2 Live load ~ 75 kg/ m^2. Incedentally this number correlates to some of the old roof design codes. I use this when assessing old roofs for pv panels.. it's a funny world! Dead loads on the beams: Say a PTFE roof covering with some ply on PIR insulation. But we need to create some kind of slope in the roof to let the water drain. I'll play safe here and allow for a concrete screed to create the fall, say a cement screed or something that averages 50mm thick (say max 5400mm span with a 1:80 fall = 5400 / 80 = ~ 70mm of average screed required once you put the bells/ extras on. Average screed density + insulation + waterproof covering = 22 kN/m ^2 thus 0.07m * 22 = 1.54 kN/m^2 say 1.5 kN/m^2 as a ball park figure. Take the concrete slab as 200mm thick as per the sketch up model. The weight of this is the density of a lightly reinforced concrete (I'm avoiding a thin slab with lots of expensive/ complex rebar)* the thickness = 24 kN/m^3 * 0.2m thick = 4.8 kN/m^2. Note: I have not spent much time mucking about with the other loads as the concrete weight really is the dominant component. Now we need to put in a ceiling and some services on the underside. Allow say 25 kg/ m^2 ~ 0.25 kN/m^2 Add up the total loads: 1.5 + 4.8 + 0.25 = 6.55 kN/m^2 say 6.6 kN/m^2 ~ about 650 kg/m^2.. Now that is quite a lot if you compare that to say a timber flat roof with say posi joists which will clock in at a lot less.. but I have a light weight warm roof on part of my house and you can hear the birds trotting about.. and I'm pretty deaf to boot! Ok now we have some loads on the roof split into two components.. the live load and the dead. I'm going to take your longest spanning beam as 5460mm and that it has to support a roof slab width of 6445mm. First calculate the uniformly distributed load on the longest spanning beam. Live load only = 0.75 kN/m^2 * 6.445m /2 = 2.42 kN/m = w1 Total load on beam = 6.6 * 6.445 /2 = 21.27 kN/m =w2 Now let's calcultate the amount of deflection we can expect: Using the formula (assuming all the load is uniformly distributed along the beam) Deflection = 5*w*L^4 / 384 E *I. Lets try a universal UK beam section of 305 (deep) x 165 (flange width) UB 46 kg/m which is a good mid range section, off the shelf and can head off problems (Architectural input) when you come to connection design and the beam twisting / buckling.. for another day. w = the load L = the length of the beam E = is what we call the Young's modulus, the elasticity of the steel I = the second moment of area = a geometric property of the beam For the live load the anticipated deflection mid span will be about 5* 2.42 * 6445^4 / / 384 * 205000 * 9900 * 10^4 = 2.67mm that is not a lot but! For the total load the overall deflection mid span will be about 5* 21.27 * 6445^4 / / 384 * 205000 * 9900 * 10^4 = 23.5mm The 23.5 mm deflection is the key! That is quite a lot for the longest spanning beam to bend, nearly an inch in old money! But here we get a bit more thoughtfull. I know that once we start to stiffen things up and get them all interacting I can reduce the overall defection a good bit. I think I could get this down to under 15mm once I start to value Engineer. The main thing for me is the glazing and how you handle the deflections.. and all that feeds back into the Architectural side.. the detailing, thermal bridging etc.. it gets reallty interesting here. Lets go back to what @George and @saveasteading were advising! Span / 18 and span / 24 @GeorgeMaximum beam span / 24 = 6554 / 24 = 273mm beam depth @saveasteading Maximum beam span / 18 = 6554 / 18 = 364mm beam depth You can see I have picked a UK beam with a slightly wider flange which is smack bang in the middle. In summary George and SaveaSteading are two highly experienced Engineers.. it should come as no surprise that they know their stuff.. all I have done is put some numbers to their experience and picked a beam with a wider flange! My span to depth ratio is 6554/ 305 = 21.4! I'm not shitting you all, I've not manipulated the figures.. I just thought I'll write write this post, do some calcs and if at the end I disagree with the other posters I'll say so and why.. but no need at my end to disagree. @DRM ask this.. now you have comment from three Engineers, an Architect @ETC, professional Contractors, self builders that have been thee and worn the tee shirt and more... time for you to make a donation to BH even if it's a tenner.. it will be good for your sole.

Plus 1 BC will ask you to do several pits around the building to expose foundations for inspection A quick and cheap job

I would have thought this was up to your BCO!, Get them to site and discuss and ask them to confirm in writing what, if anything, you need to do/provide.

Hiya folks. I do like the ICF concept but we are self builders here, not McAlpines ect ( major Contrators) who have Engineers on site checking levels etc. It's self building and we have limited resources. Ok a few options considering what you have to work with. First is ICF.. you have been pouring all day..worrying about bracing and burst out, getting the compaction right and the concete coming on time, it may be raining and windy.. by the time you get to the top of the wall everyone is knackered on site.. the last thing you want to do and are just too tired to do is to finish the top off or start thinking about bedding in fixings. Don't even try to do this at the end of the day. I would keep the top of the concrete 0- 10mm low if you want to "go with the computer"... if you want to be pedantic... not my favoured option. You need to tie the roof to the top of the wall. You can use Simpson L brackets for this which are good for uplift and shear loads. For Posi joists you can introduce a vertical noggings /dwangs if not already provided to give you a nail fixing for the brackets. I would keep the concrete 55 + /- 5 mm low and then later bed and tie down at your leisure a traditional timber wall plate 95 x 45 C16 grade timber on that. You can get it level, fix it down easily and then you can get your expensive posi joists spot on level. I may come over as a philistine but I see this all the time where.. the computer drawing says yes.. but on site at the end of the day, messing about with concrete, with local builders the mood music is.. "NO CHANCE MATE" I know you can go on ICF web sites and the posi joist web sites and it all looks sooo easy on the computer.. but on the ground it is not so. The trick is to identify where things go wrong and actually design and plan for the "shit that happens" Cut yourself some slack.. keep the concrete low and introduce a get out of jail free card for youself by way of a traditional timber wall plate as above. This way you actually get more control over the quality between the two interfaces and design packages as you are able to adjust the wall plate height and at a push it's thickness youself.. you get a fresh start with the roof levels. This can be a bit more work but it it can avoid disputes which are really stressful.. you create a zone where you can just "sort it yourself" and you make a clear break point between the roof and wall work packages if need be. This is unique to the self build thing.. we need to often balance personal stress / family pressure vs the build. I see this and have in the past been a self builder so the above is based on my own experience. You know you have the ability so if you can apply that to make a clean break between the work packages / last lot of contractors it can help a lot. Some Contractors are great and you want to keep wqorking with them.. others it a relief to see the back of them (I'm being polite here)

Faulty foundations apparently... https://www.bbc.co.uk/news/articles/cv2548v1dpyo

Some do it, some don't. Found the instructions are generally way more complex than they need to be. With way to many options that are not easy to plumb in or understand h way to easy to get wrong. Could be made really simple with a relay, this would be seamless (ish) - down to temperature say 2 deg, you have permission for heat pump to run, the relay switching at the preset temperature would make gas boiler come online and switch off the heat pump. Heat pumps normally have a remote on/off contact that could be used, the boiler has a call for heat contacts. You would need a few check valves to make sure the flow directions are correct and you don't get back flow through boiler or HP.

It’s aluminium

>>> btw, quoting people the way you do doesn't notify them that they've been quoted! 😉 @Thorfun - ah yes I do that when I want to actively avoid bothering someone - but then if they come back to the thread they can answer if they want. Thanks for the thread reminder - I had seen it but will read it through again and make sure I understand everything this time

So just as an update, no issues experienced so far, even in the high winds we have had. Was comparing the house output and the vertical array today. Both a similar kW rating, house at 45 degrees, this array vertical. Vertical array was generating 1.5kW while house was generating 1kW at the same time, this was at 11am, when sun direction suited the house array (SE) better than the vertical array (SW). So circa 50% (or more) uplift in winter performance. So fulfils the design brief I gave myself, generation between both arrays was 4.5kWh between 10am and 2pm and a sun/cloud day. Attached is a composite of the total output of house and hill top array, from the battery software.

I can't quite visualise your set-up - a drawing and/or photo would help. Like JohnMo, I insulated around the twinwall in the roof with mineral wool - making sure that I was observing the distance to combustibles limits (e.g. for the roof membrane). BC signed off on it. I don't know exactly how much of a thermal bridge I have left. I guess I could figure it out, but it strikes me that if you have a wood burner and a flue, you're prepared to take the hit on the thermal bridge.

Usually insulate around flues etc with vermiculite

Mineral wool is not combustible, not so certain of glass wool. Rockwool is certainly not combustible and is used in twin wall flues. I would be less concerned about not how much heat is trapped, but more concerned about how much heat escapes as it's a huge thermal bridge if uninsulated. We used a twin wall flue, but used rockwool around it in the roof to keep the insulation at the same value as the rest of the roof.

Downstairs I would do a simple cascade system. Supply air only to lounge (around 50 to 70m3/h depending on floor area downstairs), use a fan in the internal wall between snug and utility. Supply air will be moved by the two MVHR extracts and via the fan in the wall of the snug, the airflow will be the blue lines on the drawing. The fan could be a simple dMEV fan, like a Greenwood, they are almost silent and would run at min speed. You also need an extract in the toilet, or you could cascade the utility into the toilet (another fan in the internal wall), as you wouldn't want smell from the toilet being pulled into the utility

Joe90 - I was hoping he would advise what he required. I will arrange for him to come out for a site visit. Thanks so much for your reply.

Likewise. It didn't make sense to me, so I assumed this was more a specification/ guidance than showing real life detailing.

I've bought quite a few times from eib market, no problems, but I'm importing it via my vat registered company. Maybe they don't sell direct to consumers Fwiw I do cut down the cross connects to the size needed, then use endplates that generally cover over any exposed end. This may not be best practice but only using premade sizes seemed impractical

Through a scaffold tube, for an easy bridge?

The cross connectors are not designed to be cut to length as that would leave an exposed end. I buy whatever sizes I need to use but usually buy in small batches. I don't bother with coloured terminal blocks or cross connectors, just buy the standard grey. You seem to have a lot of end plates on your list, I'd be surprised if you needed that many. I've never found a single supplier who was able to source everything I needed so always have to place several orders. EIB market came close and cheap but they are in Europe and won't now sell to UK since Brexit. I found Hub good for some of the Wago stuff, and a decent price. I think they are local to you too. The CPC/Farnell price thing is bizarre as they are the same company. Have you tried RS? I find them really cheap for some stuff (e.g. DIN rail terminal block end stops) Not specifically terminal block related but I have found Digi-Key very competitive on other components like power supplies. Even shipping and customs from the states (which is all included in their price) they were 20% cheaper than I could buy from any UK source.

I was more thinking about spammers joining and wasting time. Though we are pretty good at catching them out.

I removed your phone number @Gus Potteras the big bad world is full of strange people who can cause trouble. If @ash_scotland88wants your number he can PM you.

I have always built cabinets with RCBO feeds coming from the main DB, not included within the Loxone cabinet. Having RCBO's within the cabinet and as the only form of circuit protection and isolation in my view would not comply with current regs. Using RCBO's or MCB's in the Loxone cabinet as a secondary means of circuit isolation I would say is fine but not something I have done for any clients.

Preference is after. The gables are the tricky bit and trying to get concrete to go off but not too much whilst having it all plumb/straight at the same time and then get a wall plate and j bolts on was stressful. Doing the wall plate post pour was arguably more work (drilling )but was easier to do, and easier to do right.

15m of 32+32 from ingoodnic here on my install, 9kW unit on the end… It was like wrestling a python.

We used Rauvitherm pre-insulated twin duct and put this in before the hardcore below EPS. You need a deep trench, but it's not that bad if you put this in before everything else. This goes through hardcore, EPS and concrete without any ducting. Our M&E consultant told us to use 25+25mm but that was bad advice as 25mm plastic isn't much more than 20mm. Our 7kW AroTherm Plus manages 1200L/h to our buffer, but I'm pretty sure there would be no remaining head for much else. Length is 8m or so, if it had been any longer it would have been worse. 5kW ASHP would have been less of an issue with this size, but most people would still use 28mm copper for 5kW. Do you know what your approx heat loss is going to be. This will help, because it house is huge and heatless is 10=kW, then you might need more than 32m, especially if plastic with smaller ID.

Hello there ash. Happy to have a quick chat with you on the phone if only to reassure. You can pm me or give me a Pm for my number, you'll find me on the internet also. I'm based near Glasgow. I hope so! Agree. It's ok to have a quick chat to understand the background but not ok to judge others / criticise their design without letting them know you have been asked to formally review under instruction from the Client. It's not professional and also basically unfair. It's not a big thing.. my designs get reviewed / checked all the time usually by an in house Council Engineer (or they contract out for checking SE services) on domestic projects, on say bigger industrial stuff ( I often work for the Contractor) by the Clients own Consulting SE. It could well be that the Architect, maybe you, did not fullly communicate to the SE what structural envelope was available to them to fit "their stuff into" and they did their best to fix it at a reasonable build cost vs intrusion into the Architectural space? It may be that the Architect did their best to achieve compliance with the building regs and maybe just did not know about these "structural bits" as they are not SE's?

We did something similar. The first time, we laid the wallplate on the poured concrete, this time we simply got the level and them secured the wallplate using resin bolts. As you can wee, we'd left enough ICF to be trimmed down flush to the top of the joists, then when the OSB went on, we used air tight foam, as well as between the joists and the ICF.

For my 6x5m garden room I did a 100mm reinforced slab over dpm and 100mm of mot1. I then put oversized dpc under the sole plates of the walls, which I could lap up the outside underneath the breather membrane once I'd built the walls. Sole plates themselves were anchored with M10 concrete bolts. For floor insulation, I put down more dpm, taped to the inside edges of the dpc sticking out from the sole plates, and then put 100mm of pir on top, taping the seams with foil tape. Then 22mm t&g (glued) osb subfloor floating on top of that.

What I did was lay a flat concrete slab (excavate, compacted hardcore shuttering, sand blind, DPM, concrete), then two courses of engineering bricks, a DPC and timber frame (Mostly 2x4 and 4x4). Then on the outside WBP to prevent racking. A vapour permeable membrane, then vertical battens and horizontal cladding. I used oak boards but T&G also works. I extended the battens and cladding down over the bricks stopping about 25-30mm above the concrete. Gravel around the outside of the slab to reduce splashing. Ideally water running down the cladding would drip onto the gravel not the top of the slab but the engineering bricks keep out any water that does. The roof is pitched and tiled but flat roof with fall also possible. The front of my building has a stable like roof overhang to shelter the door. The wall plate of the timber frame was bolted down to the slab. I did this by pushing "bolts" made from threaded rod and nuts into the wet concrete slab. These were tall enough to go through the two courses of bricks and the wall plate, big washers and nuts. Caution: I tripped over and nearly impaled my head on one of these "bolts". After that I put 50mm plastic pipe off cuts over them. Scary moment. I also put some electrical duct/pipe in the ground before pouring the slab so that later I could run SWA cable up in through it. I used a so called "garage CU" which has 1 power and 1 lighting breakers. Electrician installed Earth rod etc. The inside was insulated between the frame and another layer of WBP painted white. I wanted it strong due to tiled roof.

Funny that this isn't a routine feature of heat pumps. It almost seems like they copied what gas boilers do without thinking it through. Either that or most other climates are dry enough that defrosting is much less of an issue.

Hardcore, sand, DPM, concrete. You could add insulation between the DPM and concrete. Or heavy 3x2 slabs on a cement mix. Lits of different ways really. This what I did

I DIY fitted a MVHR. It works really, really well, however do not under estimate the work in installing. We went from a house that had mould in the bathrooms (no extractor fans) to much better air quality. Running the ducts in the loft was the easiest, for a given value of easy in the loft. Running ducts down to the ground floor took a while as hiding ducting in cupboards and also ensuring the loft end worked was more effort. Fitting the intake/extract vents in the roof was straightforward for a roofer! It took five weekends; One for the intake/extract/condensate drain/unit setup. One for the upstairs rooms (two bathrooms, three bedrooms). Another for an extension bedroom (should have hired a core drill for going through an outside wall that is now internal). Another for downstairs ducts to kitchen and lounge. Another for a downstairs loo that involved dropping part of the ceiling to fit the ceiling duct as I could not access above it. I think I could do it in half the time or less as now more confident. All my parts came from ebay, isells, BPC, Screwfix. I did the design myself with a spreadsheet of room volumes and flow rates. I went slightly below the suggested flow rates for "Normal" rates and over for Boost. I overspeced the ducting to reduce noise (ie twin ducts to all rooms as running these is not much work relatively). I fitted noise silencers. I would go higher for boost, to clear damp air quickly, however above 90% flow rate it is noticeable noisy. We have virtually zero condensation. The odd, tiny bit behind some plantation shutters on some cold nights. Some condensation on a door lock that is a cold bridge in a yet to be vented room (its the hardest to get to) and sometimes on the letterbox flap (needs more insulation!). If you have reasonable loft access and only need to do runs in the loft this will help reduce install effort allot. I assume you could have the intake/exhaust through a gable end which should be quite easy (given value of easy). Think of the condensate drain and where that goes (I suggest a soil vent spigot to keep it warmish). It is great, but allot of work. I would have a strong think of doing it again, but on balance would do it again. I did consider four individual room MVHR as these would be quite allot of work to install (core drilling, running electrical feeds) and these are expensive units. I think this would be cost neutral compared to my MVHR. Maybe slightly less work, but not much. Running costs would be more due to more fans. It would not have improved the air in non-vented rooms compared to MVHR. Your air leaks might be an issue although depending on units you can set them to run intake fans faster than extract to positively pressure the house which will help with internal air quality. This would be slightly less efficient as you are losing air that is not going via the heat exchanger. On either method consider the filters the units have. Mine goes upto M5 (A "Pollen filter" ie 50% of Pm10). Newer models have HEPA level filters. You could DIY a HEPA filter on the intake from BPC/Isells bits. Sorry that turned into an essay...

i run my grant arona 10kw heat pump, flat out , between 12.am and 5am using cheap over night electric.. during that periord at about 0-3 degrees it uses 10-14 kw of power.. my thermo stats are all calling for heat higher than it will ever reach .. its just pumping heat into the floors .. i have the weather comp set at 50 degress at -3 external .. this is into my buffer tank , but i have recordeded retirn tems of 40 degrees from teh underfllor loops.. i designed my house to run at Under floor flow temps at 35d at external 3, but this would be leaving it running all the time .. and it works perfectly, , but its way more cheaper for me to utilse the overnight cheap rate and charge up the floors as much as i can for teh 5 hour period then turn it off (cost to last year are about a 1/3 ) I have a large 4000 sqft house. all with under floor heating .. during this perior we heat bathrooms, kitchen , family room , living area .. ( bedrooms dont require heat..they stay warm) the charge into the floor make the whole house snug and warm .. we may light log burner in the evening but this is more creature comfort rather than nessesity.. at the same time over night we charge our 10kw batteries ,, this mostly enough to run our house , do our hot water via teh heap pump and electric cook.. if we get a bit of sun its enough to boost the battery by 30% (7.2kw 5 degree facing west rray) to last out till the 12am charge time.. if not and we do a big electric cook we may need couple of imported kw.. House is new, i(designed by myself )contemporay design, open plan iving areas with solar gain in winter if its sunny .. floors are covererd in either amtico , tiles with carpets in bedroom.. (wood floors what ever they are are just terrible for low grade under floor heat efficiency we learned that mistake the hard way in our last house ) we basically pay about £2-2.30 - britisg gas 0.09p kwh (standing charge aside) deending on temp say 5 degree or under to heat and run our 4000 sq ft house per day .. keeping it super comfy toastie thsi way.. we only really need to heat november / december /jan feb march.. if you woudl like any more details or soe energy graphs ask away, but using over night to pre wrm your house works brilliant, teh more isnulation and draft proofing you do to retain that heat then it has every chance of being your only heat time required.. kind regards Andy

Anybody that prefers gas to induction is, objectively, wrong.

Go and buy a couple of cheap portable Ikea induction hobs like this one https://www.ikea.com/gb/en/p/tillreda-portable-induction-hob-1-zone-white-70493503/ or even the double one https://www.ikea.com/gb/en/p/tillreda-portable-induction-hob-2-zones-white-90497166/ and try them out for a while. Obviously make sure you have suitable pans. Once you've spent some time using them, I'm sure demands will change. I once had no choice either 😉 but we do have a permanent induction hob now. One of the best things is how easy it is to clean compared to gas!

Just chipping with my own experience. We have 60 m2 of window area. 7 doors and 21 windows. We were getting quotes in mid to end of 2020, for tripled glazed, Alu-Clad windows from the usual suspects, Internorm, Velvac, Rational and Idealcombi to name a few. I prepared a window schedule with dimensions, so they all had the same specification. They all priced at a similar point, e.g. £35-40K. Then the fun began. My neighbour who had Internorm fitted, showed me his quote, from the same person at the company, going to our (same) post code. He was given 43% discount on the list price, we got 18%. A difference of around £10k. We spoke to Idealcombi to update our quote and they said they could give us an additional discount of 35%. A difference of £13K. We then spoke to some of the other companies and told them the situation. They then replied “oh, we can match that”. We went with Idealcombi since they were the first to offer the discount without being asked. They have also been very good with a warranty claim. Ultimately we paid around £430 per square metre – not fitted. It was also incredibly convoluted. We skipped the £800+Vat measurement fee and did it ourselves. We would ask (using the schedule) please make W1, 100mm wider and W5, 200mm taller. They actually, made W1, 200mm wider and W5, 100mm taller and so on. We had 17 quotes before they got it spot on. I’m from an engineering background, so specifying everything and checking that the supplier conforms is second nature. It’s laborious but don’t leave anything to chance. We also installed them ourselves. Me, with no building experience and a bricklayer/stonemason who was with us for the build. We made our own mounting brackets out of 5mm galvanised bar, because the manufacturers 3mm brackets looked a bit frail. We know a Velvac installer and we were looking at our kitchen windows, he said to me “we would put four brackets on those, two either side, how many did you use?”. “Ten” I replied. I think they will be strong enough! So in my humble opinion, the whole thing is a bit of game. All the quotes we had (every one) had a margin of at least 35-40% that could be sacrificed if necessary, to get the order, on which they were presumably making an acceptable margin. At least use a per square metre baseline price, so you can evaluate the true cost. There’s such a massive variation. I’ve seen doors at the NSBRC centre in Swindon that were £5k+VAT. Ours were around £900 and passive house rated. Good luck.

I thought I would put a post together for those that are looking for windows, replacement or new build. As someone who deals with final order placing / final quote discussions. One of the things that crosses my desk on regular basis, is that the "other supplier" is more cost effective. Which leads me to ask myself "more cost effective against what" are you comparing apples for apples? When I ask people to compare, what we generally explain is to look at the following (see below) if they are not willing to supply a copy of the quote without prices. Product - is the product similar. For example are you comparing a Timber Aluminium cladded window with a Timber Aluminium cladded window? Glazing - Is the glazing on offer from both suppliers comparable? Is it double glazed v's triple glazed for example or is it float glass v's toughened or laminate? Check that doors have toughened/laminated glazing Check that windows within 300mm of a door have toughened/laminated glazing Check that windows below 800mm from the finish floor have toughened/laminated glazing Check that windows that are 1400mm in height or above for toughened/laminated glazing. Most suppliers will start to consider toughened / laminated from 1400mm onwards, some will still be float glass. Check triple glazed glass units. Some suppliers will only toughen the inner and outer panes and leave the middle pane as float glass, others will toughen all 3 panes (I recommend all 3 panes as toughened) when required. Why? quick example is from experience, a customer in the north west of Scotland had the middle pane as float glass in french doors, the doors are recessed with wall on either side. It effectively became a wind tunnel. What happened is during high winds, the door sashes had that much wind pressure constantnly, that the door sash was pushed away from the frame slightly and a rattle effect occurred (only thing I could think would cause this to happen). As a result the middle pane (float glass) shattered. This required the whole sash to be replaced, as the glass was glued into the frame on that particular product. Timber - Is the timber comparable, are both using spruce/larch/oak/pine etc.? Are any of the products finger jointed as standard (which is more cost effective versus fixed timber, but not as aesphetically pleasing). Is the timber cut from from one section of wood or is it individually glue laminated timber? Ug values - A 0.5Ug can be quoted by suppliers but the costs vary dramatically. One of the reasons for this can be the glass make up and the gas that is being used. Some quotes won't tell the gas being used but it's safe to assume that if it's 48mm glazing it is Argon. Pay attention to the spacer distance also, not for cost but if the spacer is above 18mm, convection can occur of the gas filling (gas moves around in the unit). Hinging - Are the hinges concealed or are they exposed? Door Hinging - Pay close attention as suppliers will have quoted standard framing on doors, others may have increased the widths of the jambs to increase the space available at the hinging for plastering behind. RAL Colours externally - are the quoted RAL colours the same? Internal colours - have they quoted the same? Some will offer the standard colours such as a clear lacquer, others will have them painted - does this have any impact on price comparison. Sizes - have any of the units been split, due to not being able to achieve the size required? Some suppliers will not be able to do large sizes, others will be. Look out for compromises. Don't always look at the end figure and immediately reject a quote as being to high, compared to the others. Most suppliers will have the supply price first, then additional items such as window cills, compriband, membrane, installation etc. which are optional to the quote and not necessarily required but may be included in the total cost at the end. Most self builders like to take on the mantra of doing the whole build, others would like to leave this to the supplier or builder and or source their own materials if supply only. What is being offered with the installation service, are the installation options / costs comparible to each other? Who takes responsibility for the windows upon arrival? Generally speaking most suppliers who are installing, should be taken responsibility from the moment the windows leave the factory, to the moment the windows/doors have been installed, sign off. If supply only, the responsibilitygenerally passes to the client once the offload commences. So it is important to document the windows before offload, during offload and once offloaded. The manufacturer will normally have documentation / pictures before departing the factory, it makes life easier on whether a claim with the haulage company or whether a claim with the supplier is required (both should go to the supplier who should deal with it). Warranty - how long is the warranty, what does it cover? Last but not least, is the quote comparible? Have the suppliers referenced things the same way or are have the drawings been scaled and then referenced by the supplier (this happens a lot when no window schedule exists)? A lot of architects don't create window schedules for some reason (one the major parts of a build and most costly aspects) and problems of missing windows can be encountered, due to the elevations not always showing "hidden" windows which can be seen on floor plans. Some suppliers can miss this, which then impacts that quote. Hopefully some people find this useful, of not apologies for the long read

Cool Cool, A couple of things I've figured out along my house journey ( and a couple of things I wish I'd known before) BTW a good architect will have these sorted but sometimes they get curtailed by the existing building and the clients requirements. (i) The main entrance should be into a dedicated welcome space, ideally with some natural light shining into it from in front or above or beside. It is pleasant to have a sense of "opening up) once in the door, A vaulted ceiling or a view up a stairs to a large window can do this. (ii) This should include discrete storage or be very near to a coat/boot room. (iii) A WC should be close at hand. (iv) Think of the flow through the house like a road network. For instance, the kitchen and stairway will be big paths for traffic. These should be accessed directly and via large "trunk" roads. If there is a circuitous route and narrow doorways and hall's it'll be a pain to live in. (v) Natural light is super important, if well designed for it can give the impression of a much larger space without any of the actual cost or hassle of building it. (vi) Light from the South is ten times better than E/W and 100 times better than Northern light. (vii) Tricks to get it into a house (a) South facing windows and glazed doors (obviously!) (b) glazed internal elements to suck some light into the inners. ( fan lights, glazed internal doors etc) (c) Atrium style skylights to get it into the centre of a fat building. (d) Clever use of mirrors and colour to reflect it inside (viii) You cannot have too much storage (ix) Natural light entering a room from two directions can make it feel much bigger. (x) The ratio of ceiling height to room size is important. My parents with 2.65m ceiling in their 4m*4.5m kitchen feels much taller than ours at 12m*4.5m and 2.7m high. I'm sure there's more.

No, the reason for this, is it's a quotation and usually will not cover this and usually irrelevant to a quote comparison. The points you raised are covered by indepenent 3rd party certificates in most circumstances and not covered in a quotation. No specific requirement but it is standard practice with most manufacturers and a safety aspect to toughen glass when the height is in those regions. As for the doors. You are making either an ill informed opinion or you have no experience of this issue. All units will be tested to a certain class / pascal rating. That particular system is tested to 1800 pascal rating which is in excess of 120mph wind speeds, the security class of the system is WK2 and 5 point locking. If you think a tunnel effect is implausible, then supply an alternative theory. As for being rubbish, that they are not - I assure you of that (check out my introduction for more information). Fact is, the wind pressure against the sash was forcing the sash away from the frame. So with the wind pressure increasing/decreasing over several hours it appears that has caused the sash to hit the frame by causing a couple mm gap and has been repeated over several hours has likely been the cause of the issue. It is the only explanation we can think of that would have caused it and without put the unit in a wind tunnel to test, the only logical explanation (from myself and several others). Again, not shown on a quotation and dealt with via certificates and therefor not always relevant for comparison checks. I never said it was. Therefor, please don't imply other wise. What I said was I specifically didn't mention Uw values, the main reason being they become extremely important within PHPP calculations for a PassivHaus where the space psi value can be the difference between a pass or a fail. Otherwise, it is not the sole reason for a customers choice but it is worth checking in the comparison and in hindsight should have been mentioned. Again, not covered within a quotation. This will be in certificates and installation/adjusment manuals and therefor not relevant to a quote comparison. All valid points but again, not covered under a quote comparison but some quotes will advise of the relevant BS/EN EN numbers on the quotes. Most customers will not be aware of these and it is the suppliers/manufacturers responsibilty to supply this information. As well as supplying a performance declaration for all units supplied within any installation.

Put them on the roof but I don’t want them on the roof.

Until there is Parity of Esteem among post 16 courses. @nod , @SteamyTea, @IanR (?) , @ProDave and @ToughButterCup will continue to blow our collective fuses

Yeh, I have properly balanced the whole system a few years ago, down to using a multimeter to get the temp to 12⁰ across the pipes....took 2 days. I was hoping for a quick fix this time! What I don't understand is that on all the hot rads the LS is literally barely open, not even 1/4 turn, even those the farthest away from the boiler.

It sounds like they ticked all the boxes except for the "attention to detail" one. As above, not very surprising, but very disappointing.