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It has taken months but we finally have the stair and balcony glass in place. Best of all it went in with no mishaps, chips or scratches. There is still lots to do but this was the main thing stopping us from moving.

Hi all. I can't quite see where all the supports are to the steelwork but there are plenty things that could be going on here and the SE looks like they have spent some time thinking this through. It's looks quite elegant really even though you have a bit of cantilevered floor that with hind sight you may not have chosen at the Architectural stage. Let's start with the basics. A steel beam is designed for "pure bending" called its moment capacity (Mc). This is often where the steel starts to yield and fail but the beam does not distort or twist sideways. Beams can also fail in buckling where they just twist and distort and collapse suddenly. Often you find buckling (Mb) is the governing criteria. We call this (Mb) the buckling capacity of the beam. Long beams buckle easily so what we do is to fix floor joists, floors or other beams to them to prevent them from distorting / twisting / moving sideways and thus we increase the buckling capacity as we shorten what is called the effective length.. that is simplistically the distance between restraint positions. If we do this well we can in cases increase the buckling capacity up to the Mc capacity and thus get most bang for our buck. Lets start with beam 8 and lets assume there is not much restraint from the floors as the joists span beam 9 to 7a. The SE may be using quite a stiff connection from beam 9 to 8 to stop the twisting / provide torsional / twisting restraint to beam 8 thus increasing it's Mb (buckling capacity) significantly. If you don't do this then often you need a heavier and deeper beam. They may also be using beam 12 to further reduce the effective length of beam 8. As you come up the stairs on your left hand side there is the stringer with spindles above and behind the stringer there is a space before you seem to find the first potential support. It actually looks like the end of beam 11 is supported by beam 7a. Thus beam 11 spans from 7a to beam 10.. it is beam 10 that is holding up one end of beam 11, 7a the other. Now for beam 10 to hold up the end of beam 11 it needs to act as a cantilever off beam 8, but if beam 9 was not there then beam 8 would just twist and it would fall down. I think the SE has designed a very stiff connection between beam 10 & 8 and 8 & 9 so that 9 & 10 act as a continuous beam, supported at one end by the outside wall and by beam 8 at the joint. Lastly you also find that where beam 9 rests on the wall the SE has made sure there is enough back weight to stop this end of beam 9 lifting upwards.. like ballast in a boat. That looks like one possible hypothesis but a caveat is that we have not seen all the info, support detail and the global structural design. Lastly the diagonal bracing. I have touched on a few but not all the facets of this but you can see that the steels will be doing a lot more than just carrying the basic loads. Everything will be wanting to twist, bolted joints will slip here and there so I think the SE has introduced the diagonal bracing to stiffen things up. Also the diagonal bracing may be providing global stability to resist wind loading. In summary don't remove beam 10 or any other for that matter without asking your SE! Also don't let your fabricator / metal worker change the SE's connection design in any way without asking. If you have read this far then thanks. Gus

It’s gone . Gone to the great skip in the sky . Not a mistake but a mere oversight

I would say they both look cramped. How about putting the bath where the sink is, or where the toilet is on the first sketch. then sink and toilet where the bath is.

We're opposites again lol. As the top chord of the posi-joists takes up a good 50-60mm depth or more which is dead space anyways, I always recommend putting the insulation up in between, tight to the underside of the upper deck, and to hold it up with either fishing line or a nylon string and a staple gun. Then we run all the services underneath the insulation. Helps a lot with keeping most of the service void open and clear, and I prefer that for electrical etc so you're not cutting or compromising insulation where there are MVHR vents / downlights / speakers and so on. The insulation can go in early and be done with, and IMO it's a far easier install all round. Much of a PITA when the insulation fitters have pushed a cable off point and you need to go digging through acoustic insulation to find it.

I never just chuck stuff in these days. Always have my circular saw and sledge hammer at the ready. Always pack it like a suitcase ready for a flight ✈ .

I was sick and tired of trips to the recycling centre so hired a skip. Got it 90% full and was waiting for digger driver to come back to clear an area and get a few more bits through in before getting it collected. I'd say he put in another one or two skip loads in to the one skip by smashing it all down, layer by layer. Dude saved me at least £250 🤣

@Marvin, I just cranked the maths on the figures that you provided, not on my figures. For my own house the numbers are a lot more compelling. I have a 3 storey house with ~ 250m2 floor-space with UFH on the ground-floor slab only. The inflow on the MHVR inlets is around 19°C, but we keep our internals at around 22½ °C. We don't have any heating on the top two floors (except a couple of small oil filled rads which my HA system turns on for a few hours every night during the coldest three months). If the 0.5 ACH was coming in at 0-5°C overnight instead of 19°C, then we would have needed some form of decent CH system for the top two floors. You just can't look at one component and try to optimise it in isolation (not unless your name is Boris 🤣). You have to treat the house as a whole. You also can't just use averages, because if you want to avoid freezing your bollocks off, then your system still has to cope with that Dec-Feb window when the night temperatures can hover not too far above 0°C. We did our MVHR for ~£2K, labour DIY. We avoid maybe £4-5K of CH costs and needing to install gas, etc. Ignoring the avoidance of replacement CH solutions, the payback period was under 3 years. As well as living in a fresh damp-free environment. IMO, this one was an absolute no-brainer. You do need reasonable access for maintenance / cleaning, say once a year or so.

It is never as simple as you think. Solar PV is a good companion to an ASHP but it is wrong to think of it in terms of "solar PV will heat my DHW" The reality is "Solar PV will reduce my electricity bill" The trouble is solar PV is maximum in the summer and of course only in the daytime, with max output at mid day. so you have to think how can I shift as much electricity usage to close to mid day as possible? Three things work for me. No 1, I have the ASHP timed to start heating DHW at 11AM, there is a reasonable chance of decent solar PV generation by then. No 2 use the big appliances one at a time around mid day. and No 3 install a solar PV diverter, so if nothing else is using the PV generated power, it will go to the immersion heater.

Sadly the inevitable cost of replacement pumps will push you even further back on the breakeven. As you say you've already got the system anyways, be mindful then to maintain it and keep the sump strainer / filter clear and routinely check the cold feed sensor to make sure the pump NEVER EVER runs dry. That's instant suicide for the pump and bye-bye money.

You struggle to get discernible answers about gas combi boiler features in the plumbers merchants TBH. Drop the words "phase change material" in and watch the poor buggers melt......

NO, he still has the walk on glazing 🤷‍♂️ 🤣

That’s very impressive, well done 👍

Precisely. There are no mistakes on my build . But there are some interesting choices .

Because you have the best practical advice to hand at all times, and nothing goes wrong.

On my private builds? There will always be unknowns in a refurb, so nothing to make me hurt. On commercial projects: 1. Doing a trial hole which showed topsoil, a little fill, then solid clay and then designing 300m2 of building with conventional footings. While digging the footings the bucket went through into peat. The clay was a compacted capping. Had to very quickly redesign with piles and beams at our own expense. Lost 2 weeks and a few £k and could have been so much worse. 2. Is it a mistake if you spot it first and correct it? Woke up one morning long ago, knowing my setting out of the day before was wrong. Asked the boss for the landrover and chainboy, before coffee and prepping for the day. Went to the spot and adjusted the trunk road alignment to point at where the bridge would be. Back to the site office, Boss said 'everything ok? and never asked me what it was about ....sound man. Not that I would have minded saying, but he didn't want to know. Moral...dreams can be very constructive. 3. Another issue setting out a big culvert, using a theodolite, over an obstruction. I used a spirit level as a line, but used the wrong side of it. Told the GF that the foundations were in wrong. How did it happen? Fair enough! Any easy way to rebuild it?...yes I gave him a method, No more said by him or the big boss, or anyone as I think no-one was told. That has lived with me as how problems are handled....everyone makes mistakes, better to know about it and sort it, and no point scoring or shouting.

But SA are still not selling to the public then. They’re purposefully divorcing themselves from the mammoth number of enquiries and deluges of email regarding their products, and that then falls to the “approved” folk.

My site experience kicking in again If we insulate before electricians or plumbers They either pull it down or aske us to remove it If your plumbers and sparks are happy to breath the fibers in Go for it 😁 It’s easier to put it in first as Nick says But check with your sparks and plumber first I bet at least one has an allergy to the stuff 😷

Bath where the basin is; WC, sink, towel rail then shower down the window wall

One of those exercise/pressure points knobbly rollers mounted on a threaded rod makes an excellent levelling roller and they wash clean really easily

Cool stairs

I've set our heat pump to do DHW on a number of criteria: 1/ between 0030 and 0430 (Octopus Go cheap tariff) 2/ whenever the PV has been putting out greater than 3kW sustained average over the last 2 mins. (It has a minimum "ON" time of 10mins, but remains on as long as the solar is >3kW and the tank is below the 50-deg target) 3/ whenever there's a surge in use of DHW (defined by the mid-point of the UVC drops below 40 deg C) 4/ manual "boost" button pressed in the loxone app. So far, this has never allowed us to run short, and never had to use #4. #2 is a rough heuristic for "is there enough spare generation to run the ASHP". it's not great as doesn't allow for the kettle or oven immediately going on, or sun dipping behind the cloud, but it seems pretty good on average.

Pretty much. Care to redo the maths, using the Kelvin scale? 🙂

Yes, so the position of the flush plate is set in stone as the max height of the pan governs where the flush plate will reside. You cannot have the WC height at one level and the flush wherever you like with a fixed frame. FYI the height is perfectly normal for a WC. WC and basin vanity units are max 830mm factory height off finished floor level, and the flush plates are usually in the front so at around 700mm off FFL. When discussing bathroom layouts with clients, I mark out the top of the basin and the top of the bath and they all shriek "that's wayyyyyyyyy too low!!". Then they go home to the house they've been living in for 20 years and realise that's exactly what they've had all that time. Top of bath at ~540mm of FFL looks like a high shower tray, even more so when you mark it on a wall in an empty room. Once your pan, seat and flush plate have been fitted, this arrangement will look perfectly normal.

We installed two loos (Toulose?) at different heights: one a good bit higher than the other. SWMBO and the grandchildren prefer the lower of the two. Then, in triumph she comes to me and shows me an authoritative article about the best level for a human to read the sports news. The lower the better apparently. Squatting is best .... I'll try and find the reference. I seem to remember that the article took no account of those of us who have knees that are shot .....

Welcome. Just in case - excuse me if you've sorted this out - are you sure you can extend the house that you are buying? Certain sure? I ask because I wouldn't want you to buy and then find out the hard way that because of [... ] you can't extend. Ian

So you said that Sunamp won’t warranty unless it is installed by a registered installer ..? But now it’s competent person.?? A competent persons scheme ..?? Or someone who can prove competence ..?? All of these are different and tbh it gives me (and probably any rational person reading this) less and less impetus to actually use Sunamp as a product as they can’t even define their own terms or decide what is actually warranted.

Awesome, thank you both. @Russdl especially that towel tree. @Nickfromwalesyou confirmed several suspicions of mine - I strongly approve of KISS. cheers

I find I can self use almost all of what a 4kWp solar PV generates just by self use and the immersion heater diverter, which makes the case for batteries harder to justify. It really only seems to be a benefit if you have a larger PV array so harder to self use it all.

Was also used to find out where the terrorist were staying in Munich 1972.

It becomes even more complex if you have off-peak (e7) electricity as well! Do you set the heat pump to come on in the day when there might be solar generation or in the night when electricity is half the price?

I've been beating myself up on this exact same mistake. But we were being slate roofed in 2019 and we had a hell of a time getting a competent contractor, scaf. and materials organised as it was. To throw another half-dozen variables into the mix just seemed a bridge too far when the gains from PV were so much less tangible.

I have four so far... 1) Trusted the kit suppliers subcontractors to erect my house. 2) drilled a borehole and didn't get enough water. 3) just to be sure I didn't get enough water drilled another borehole...to waste some more money. 4) my current mistake highlighted by the energy cap rise was not putting on the solar PV when I was getting roof slated. Silly mistake.

Word of mouth is best procurement pathway. Forget LDC plan well and build in waiting time.

Easy to work out read building regs for your region. In Scotland it's basically 0.5 ACH. So calculate the internal volume, divide by 2. That's the basic normal flow, add 25% for boost. Choose a unit that flows your boost figure at about 70% or lower it's rated capacity. Extract in wet rooms and kitchen, supply everywhere else. As Dave say semi rigid is easy to install, just plan ahead.

Reading through this thread so many things rang true. Just checked my gallery on my phone and i erected my Hereas fencing in March 2017 and reckon I got another 2 years to go. There have been gaps in construction where very little has happened for a month or more as I have other commitments. I think I was naive with the costs and time it takes and over spent early in the build. Also I had limited network of trades and employing someone cold found in the local free ad is not recommended. My initial passion for project has been sucked away by stressful conflicts of time, cock ups, redos, and seeing other builds go up and now lived in since I started. Now still at it and in the third national/international crisis since start. The more prices go up the more I have to do myself. My advice to anyone starting is decide the max you can afford then divide by two to get your build cost budget. Never again.

Trusting next door neighbour builder and ending up doing the single block wall after strip foundation was done. Just realised how naive we were until the building inspector questioned on joist span and luckily I was present. SE mentioned the joist span at 350mm, we ordered the material to do it at 300mm and the builder did at 600mm later showing some online tool calculations. Even for warm roof he was using 18mm osb board at top layer saying taping will air tight it but initially was told will do with caber-deck. Also we were paying above market price in midlands for the work done but was convinced that we will save by doing the works together. Went back to SE and he rejected the 600mm span but okayed for single block with EWI, amended the plans. Now fighting it out to get the work to be corrected for the payments already made so far. They were also doing the outbuilding and if we compare both works there are major differences. Cavity wall with good insulation, joists at right spans etc for their building. Not sure how someone can sleep by doing a loss to others and making gains from it that to being a neighbour. Lot of lessons learned and hopefully we correct them without incurring major losses. Back to market to find right professionals for the rest of the work.

One advantage of MVHR is that the ventilation in an airtight house is controlled. With trickle vents on a cold windy day there is lots of cold air entering and on a still day there may not sufficient air changes and the internal air may become stale.

I built the house in the wrong place, do I win? 😃 Long story but it ended up about 18” from where it should have been. Clearly I will have to live with it but it annoys me every time I think about it. Nobody else has noticed or will ever.

Interesting topic! I settled on 125mm cavities with knauf 32, should have gone up a thickness or two! Making up for it with extra floor & roof insulation (bungalow, so lots there)

Welcome welcome. Spend £150 ish and buy a copy of PHPP. With an engineering brain it's actually quite possible you'll enjoy it. Looking at the numbers (which are all just school level physics) brings amazing clarity to design in an industry that is rife with misconceptions.

Thinking I could do it on a couple of years on my own....getting there now though 6 years on although only 3.5 for the house. The rest was clearing the site and building the garden room.

Not yet, but (conveniently) one of my daughters has since met and settled down with a guy who specialises in laying LVT. Only trouble is he's so good he never has any time to do jobs at 'family' rates 🙄

Have a read through my blog @Jeremy Harris and others. You have Slab losses, wall losses, fenestration losses, roof losses, air exchange losses, and thermal bridging losses. You need to design a house with a sensible balance to optimise so that you get a delta £s invested on any one that gives the best drop in heat losses and therefore delta £s in running costs. As with my and Jeremy's calcs, you don't need anything too sophisticated like the PHPP model which as so many terms and adjustments that it is intractable to make trade offs. With TF, as Dave says 8×2 + an extra layer of slab insulation can get a U-value of 0.12; slab and roof same ballpark; decent triple glazing under 1.0. Once you are in this domain 40+% of your heat losses are from air exchange if you have a pretty airtight house and MVHR; up to 85% if you use poor quality conventional build techniques and no MVHR, so you need to make your house airtight by design. The MVHR means that it always smells fresh because you are continually replenishing with (reheated) external air. If doesn't matter how good the nominal design is if your builder doesn't bother putting in the roof or wall insulation where you can't see -- as many have discovered with a FLIR camera once they've moved in. Ditto thermal bridges on steel I-beam crossing the warm / cold divide. The single biggest cost component in our house was the natural local stone skin -- which was a planning requirement, as well as looking nice. As to the near-passive performance, adding this was maybe 15% of the cost of the skin, but then again I use a 3kW inline heater to heat my water-based UFH system and our internal temp is ~ 22½°C everywhere, all year round. Putting the water-base UFH loops in the slab cost ~$2K and no other CH installation, rads on walls etc needed. (The 22½°C is because a pair of OAPs like it that way.)

The mantra on this site is insulation, insulation, insulation, especially with the energy crisis looming. Some here have virtually no heating because their insulation is so good, and you only buy insulation once. My heating comes on a few times fir a couple of months only.

You can only use rainwater for limited non-potable applications, such as loo flush and washing machine. You will then have a third water system in the house. If it runs dry you will need to top it up. The water must not be left to stagnate. You will need to store it, treat it and pump it. I have looked into this and you are wasting your time and money.

You thought you were on mate's rates.

@dpmiller thanks again for posting the link to that Iver thread. @andy top, top tip. My quarter turn isolation valve was closed. Its now open and the flow rates are epic! In the words of the plumber that installed ours... "...Not checking pump / gate valves are open is 1st year apprentice error. I’ve not had one yet which has caused any issues." Feel free to put ours down as No1 if you wish. ?

Mine is installed in the loft, hung from the rafters and it cannot be heard unless on boost ?

Friend of mine got in touch yesterday to ask if I could replace her living room light, her new smart meter showed it costing over £2 per hour to run ….. 5x5w LED’s told her to keep the light and Chuck the display in the bin!