Alan Ambrose

I think they've always been 10 years.

OK some progress. Now I need to check all my inputs and back out the psi thermal bridge value... Also had to trace my dxf file for now (rather than getting a direct import). Couple of hours work so far.

+1 suggest either leave the aluminium showing, powder coat a different colour if you need to or ... cement board over and render on that. If there's a chance you need to get at the blind mechanism and can't maintain it solely from below, then the 1st option or some kind of removable rendered board would be good.

I've been looking at some EPCs on older houses and reminded what a load of nonsense these are. For 11 flats in the same very pretty church conversion: (1) All electrically heated, thick brick walls, and no obvious differences - the EPCs range from F to C. (2) For the C, the assessor assumed the wall, roof and floor were insulated. Unfortunately, that's not actually true, but doesn't stop the estate agent advertising it as 'C'. (3) I see for some of these assessments 'Boiler and radiators, electric' scores 'Very Poor', for some, the same scores 'Average'. Maybe something to do with when the EPC was done? OK a pretty Georgian house this time, 1870s maybe, no insulation to speak of, single glazed etc: (1) EPC E, fine. (2) 'Could be' EPC C if you insulate floor, walls, roof, replace boiler, double glaze windows. £250K maybe? And it's in a conservation area, so extra insulation either extremely difficult or impossible. Yeah, a rant.

Unless you can get 2D views exactly from exactly the same PoV as the photos, a 3D model is better so they don’t have to CAD it up again. Also the architect can act as ‘art director’ but will almost certainly sub out rendering work and add a %. We used google maps views for the background images and supplied example images for the textures for roof & wall coverings etc (depends how realistic you want your montage to be). Fortunately it was a sunny day when google drove past.

>>> patch panel, patch leads, switch, data cabinet I'm surprised people use a patch panel rather than just terminatiing the network cables and plugging them into a 12/24/48 port switch. You're not going to be doing a lot of patching-this-to-that and then re-routing stuff six months later. Also, the 'data cabinet' doesn't need to be some big heavy data centre-like thing - e.g. they have lightweight & shallow cabinets for musicians. e.g. https://www.bax-shop.co.uk/19-inch-racks/innox-ina-sr4-studio-rack-4u I guess if you're using Loxone etc and switching a bunch of mains, you need a bit more room. Suggest 3 or 4 sockets for cabinet or a 4/6/8-way IEC strip like they would use in a proper cabinet. This kind of thing: https://cpc.farnell.com/pulse/pds8-c13/uk-mains-plug-to-8-way-iec-c13-switch-panel-rack-pdu-19-1u/dp/dp36294

Fine if you can get it - not much extra install costs - it's only one cable after all. Will be expensive if there's no 3P transformer near though.

I find it depressing that 'everyone' is running a heist these days, even governement departments. It seems to be accepted practice.

I should say I did the latter once (I did the CAD work) and the results worked out well. The parts were fairly cheap since they are small and commercial 3D print pricing is largely based on part volume.

For some Crittall windows, I just ordered a couple of fairly ordinary 2G panels weighing about 50 Kg in total from an online supplier. Cost was ~£650 inc delivery (delivery was £20 from memory). So, £315+VAT seems good value to me.

Just to report back - Sika offered to train and supervise workers and put me in contact with their product distributors. I told them that I was trying to to find already trained and experineced workers. It seemd a bit strange to me - but it turns out they don't have an official list of 'Sika-authorised' contractors, but have undertaken to send me some unofficial contacts.

Like @Pocster said, you have to be prepared to say 'no'. I also think you need to start to nip things in the bud as soon as you detect some initial nonsense, otherwise you signal them that they can take the piss. I appreciate this is sometimes easier said than done. If there is a true 'undiscovered problem' I do try to be sympathetic. As I've said elsewhere on BH - bigger contractors will sometimes just try this on on a bigger scale.

I think you need to post an image and a drawing - it's too much of an ask for us to imagine a 3D design and its context from a text description.

I wonder whether you've just been sent an early/unfinished draft? I wouldn't sweat it, just send the problems back and get them changed. To set the tone, maybe tell them you're surprised and I hope you will get an apology.

Yeah, you can bet that all the planners and the inspectors own cars and have places to park them, thank you. I met a guy recently who designs cycleways in London and whose job involved removing road space for buses and cars, sometimes ending up with ridiculously big pavement areas. 'We should all be moving to sustainable transport he said'. Yeah somewhat true for the younger and more physically able segments of society - but what about parents with young kids / old people who are not strong enough to be thrown around in buses / delivery vans / contractors who need to take their van and tools to site / people who need to pick up heavy or bulky stuff that they can't take on public transport etc etc etc. Yep, no provision for them.

Hmm, tricky - a typical problem with plastic sitting in the sun - or just aging. A long shot - if you can figue out what frames they are - ask the manufacturers. Otherwise ask a teenager to CAD them up and send them out for 3D print (better quality than a consumer-level 3D printer.)

+1 keep it simple

>>> might be worth getting a 10t digger and digging a deep hole +1 even a smaller one will give you a clue. Cheaper than an SI in the 1st instance. Anything sandy and you're home and .... dry 😃.

>>> a serious bit of kit That, pah, a kids thing - could probably hurt a soft human some though. The Hatton Garden guys didn't seem to bolt theirs down and it was horizontal. I wonder how that worked - some kind of frame maybe? And that's, say, 400mm? No rebar at all?

Ah, nice.

Ah, I think you can do some back-of-the-envelope calcs to satisfy yourself. If you're a CAD guy then you could do the stress analysis in Fusion or similar and get some approx results. Approx because wood, strictly speaking, is anisotropic (i.e. it has different characteristics depending on the orientation of the load to the grain) and Fusion doesn't do that. You're going to use a safety factor of 2 or more likely 3, so rough approximations all wash out. (1) Do a simple loadout calc using the quantities and densities of the various materials. That'll also give you the quantties to order. Don't sweat the detail i.e. the fixings and the light/small stuff. Add some for live load, wind load etc (standard BC values). This is a super lightweight building anyway so the numbers will all be small. (2) Maybe read the beginning chapters of an undergraduate structures book. Ignore most of the maths, but get a feel for where the shear and bending forces are and which directions. For example, the roof loads you have will 'push the eaves away from each other'. Maybe consider a metal rod or smallish beam in tension between the eaves. You're building a larger version of a shed, so you don't have to stress yourself too much, but some basic understanding of structures would help. Otherwise find someone who can help, maybe informally, so you're not on their PII. If you like, make a balsa wood or cardboard model and see how it breaks when you load it. (2) To convince yourself and maybe anyone else. Take one truss, maybe full dimensions rather than scaled. Load it approximately with the loads you calculated, maybe measure the defelection. Then stress with 3x the load and/or until it breaks. That gives you your safety factor and some confidence. p.s. (a) You can pretty much see from inspection that it'll be strong enough, maybe with a bit of attention to the joints and the eaves support I mentioned. (b) Is there a worry that any moisture ingress will destroy the MDF? As others have said - would you consider just simple treated CLS rather than I-beams?

Yeah, I was sort of aware of that (I don't know much about SAP). Seems to me that PHPP is a bit more sensible in that, if you don't put in any bridges, it probably overestimates the straight U-Value heat loss and partially compensates for the missing bridges. Have installed Therm, so will give it a go.

Thanks for that, and yes, those instructions are well written. Fusion makes some pretty temperature plots (in 3D) (see below) but doesn't do the last step of calculating total heat flow. Do you have an idea of how well the standard details match real cases? Presumably if they work for standard modern estate builds they're a 'bit high' for better insulated designs. I see from the doc that the BRE have doubled some of the numbers between SAP 2012 & 10. They say part of the rational is to encourage people to do their own calcs. Well great if that was easy. Re: windows I found that e.g. Rationel publishes U-Values and psi-values. I assume other suppliers do the same although I have not looked. How reliable are they - anyone's guess.

IF crazy expensive, it may not be too hard to have fabricated yourself. Assume folded aluminium, powder coated, PIR behind?