SimonD

I have to say I think that buildup is very weird as you've got layers of incompatible materials, thus you actually lose a lot of the benefit of the woodfibre board. Who designed this because it would be much better to have designed the buildup with the flexible woodfibre between rafters and then woodfibre boards on top of the rafters. This would give you the benefit of the materials, plus extra decrement delay and better hygrothermal performance of the envelope. However, if you're still looking for alternative supplier, you could try Ty Mawr who sell the Schneider Holtz woodfibre products, or as has been suggested above, Pavatex Pavaflex. You could also try Hunton - huntonfiber.co.uk - a Norwegian company. Good luck

I'd suggest finding a specialist broker, I'm not sure your standard self-build underwriter would know what to do with this one as a collapse of tunnel could be rather expensive to fix.

They're not wrong. A lot of poor understanding of timber frame out there in England. Where we live I struggled to find a timber/builders merchant that even stocked 38 x 140mm cls so I had to buy it by the pallet. One of my bugbears is poor storage of timber even by suppliers so you can end up with saturated stock for your frame, which is a no-no for a good quality frame (and good internal finish). This is so often overlooked that I recommend if you do go down this route, you make sure the moisture content of the wood is checked before installation - do this yourself or make sure your chippy has the means to do it and does it! However, like @the_r_sole says, find the right engineer (ours specialized in timber and steel frames) and a good chippy with the knowledge and you'll be good to go.

No they don't. There are plenty of very large commercial projects using what I explained was a traditional fully supported standing seam roof. There are plenty of published details. I personally have a copy of the Federation of Traditional Metal Roofing Contractors Guide to Good Practice because I've installed this type of roof. The fully supported traditional standing seam roof is used both for commercial and domestic purposes and has been for decades, if not more than 100 years, more widely outside of the UK. As I think I said, we're talking different products designed for different build systems. For a domestic project, you're unlikely to get any supplier to sell you the systems used for this kind of commercial project, because it's not worth their while due to the normal size of project.I spoke to a few for my current project and the closest I got from one of them was an indication that I might get some offcuts from an airport development. Typically the commercial standing seam roofs I think you are refering to have a much higher upstand, but you'll find they're similar thicknesses to slightly thicker at about 0.7 - 1.2mm. They tend to have a narrower cover at about 400mm or just over IIRC. They also often consist of a sandwich construction with double layers of steel- corrugated below as a structural deck, insulation, and then the standing seam (e.g. Kingspan). I've come across one traditional standing seam product by Euroclad (basically Tata Steel Colourcoat Urban), that can apparently be installed just on battens, but in this case, I'd be concerned maintenance access would be severely compromised. The fundamental fact is that the OP asked whether sarking boards and breather membrane were satisfactory for supporting a traditional standing seam roof and the answer is that yes they are. Sarking boards are actually preferred to osb and plywood as a substrate because they provide better through ventilation to the back of the metal. Plywood is the popular installers choice because it has good pull out strength for nails which reduces installation time and osb is third because of reduced fixing pull out strength, so you either have to increase the number of fixings or use screws instead of nails in high wind uplift areas.

I'm not sure of you're talking cross purposes here. The issue with the hip on a traditional fully supported standing seam roof isn't as described above because you would simply form shorter trays from the coil to account for the effective roof length. Indeed, this would also be done if you were ordering prefabricated standing seam sheets as you'd pull the required measurements off the as built roof. You wouldn't experience the same wastage compared to a standard length corrogated metal roof sheet, nor would you experience problems cutting each tray to fit the angle of the hip ridge - this is bread and butter for a standing seam contractor and is very easy to do. On traditional stending seam, there is not overlap. The coils are sold in certain widths which can be specified, the most commog being a cover between seams of 430mm, 530mm and 600mm, with corresponding coild widths of 500, 600 and 670 for 25mm standing seams. Not on a traditional standing seam roof. This requires the metal to be fully supported. However, I do wonder about the necessity of this buildup I think the roofers could easily have left out the 9mm osb and first layer of breather membrane unless they were worried about wind wash on the insulation where membrane would be sensible. Otherwise, it's absolutely the correct buildup with 18mm supporting osb and membrane under the steel roof. This is not correct, you're talking different a different roof finish compared to a standing seam roof which does require support, unless the OP has got the terms confused?

Assuming you'll be using traditional sarking boards at 22mm thickness these are fine for a standing seam roof. Just make sure that if you do go for the standing seam you use a marginally thinner sarking board at the eaves for the eaves flashing. With traditional standing seam it's often the labour that's expensive and this will depend on the number of penetrations in the roof and its shape. If it's a simple rectangular shape, it's a really straight forward and quick process. You can even buy ready fabricated trays that clip together saving even more on labour. I've installed both and love both materials, but I think my personal preference does now lean towards the metal.

Give Promain a call. They have lots of anti slip paints and will be able to tell you which is best suited to osb. Here's their pages for wood floor anti-slip paints; https://www.promain.co.uk/anti-slip-paints-and-coatings/anti-slip-coatings-for-wooden-flooring.html

The flat and lean-to roofs are pretty easy, the gabled extension may or may not be. As you've illustrated the design, it has a fully vaulted design which really needs the input of a structural engineer first as there are various options as to how to tie the trusses - this will have most impact on the cost. You could use a steel or glulam frame which tie the trusses at the ridge, or you can use ridged or cable ties. Steel portal frame may be the cheapest option as it could be as little as a few grand, but as already mentioned above, it depends on the details.

I've used loads of stainless in various widths and it is very malleable. If you wanted, ping me a pm with your address and I'll pop a few meters of offcuts, probably 75 or 100mm width, in the post for you to see how it works. If it's too wide you can actually cut it with scissors. I use Robinson wire cloth, better prices than the Amazon link. https://www.robinsonwirecloth.co.uk/online-shop/Soffit-insect-mesh-stainless-steel-30m-roll-p49612077

The 60% rule came in a couple of years ago. If a supplier is supplying and fitting a qualifying energy savings measure, like a heat pump, and lets say charges a total of £10,000 ex vat. If the supplier has to pay more than 60% of that to buy the products and materials then the vat charged needs to be apportioned between materials and labour. Materials gets charged at 20% and the labour at 5%. If the total materials is below 60% of the total charged, then the supplier can charge at the lower threshold of 5%. This is warning bell no 1 with your quote. If he hasn't done his own heat loss calcs and merely relied on an incorrect epc, that's warning no. 2. He really needs to do this himself and also carefully design the heating system for a heat pump. Just chucking in a heat pump is unlikely to yield promising results. It looks like your existing radiators are being kept in the new system? That is not a good sign either.

I should probably also add that if the quote doesn’t exceed the 60% vat rule the whole supply should be 5 % vat.

Nibe is a leading Swedish manufacturer of heat pumps so no worries there. However, I would check your supplier as I don't think they have treated your installation correctly for VAT purposes as they've quoted you a flat 20% whereas I believe it should be apportioned between materials and labour with different VAT rates. Not a good start for a potential contractor as Nibe actually provides guidance for this on its very own website. https://www.gov.uk/government/publications/vat-changes-to-the-reduced-rate-for-energy-saving-materials-2019/vat-changes-to-the-reduced-rate-for-energy-saving-materials-2019 https://www.gov.uk/guidance/vat-on-energy-saving-materials-and-heating-equipment-notice-7086#para2-9 Also, has the company provided you with their own heat loss calcs? That would be useful so you can verify the claimed reduction in heating costs and RHI and of course the sizing of the heat pump. At least it'll be neat and tidy they say...

Our planner wanted a chimney too. I wonder what it is about planners and chimneys. On our house the addition of a chimney made the house look like a ferry sailing off to sea. I've built the house without the chimney but if there are ever any questions I can show them that the structure has the base for the chimney so we can add it on in the future. Nothing in the planning rules to say by when you have to finish the build. Anyway, could you do something similar to avoid the chimney yourself? Just an idea like ?

Okay, so I'm slowly progressing with this, along with all the other things to juggle while building on your own. Can someone point me in the direction of manufacturers/suppliers for a 300l accumulator suitable for external installation as I'm going to really struggle to get this inside but have an ideal place outside where the mains comes into the house. And also the same for thermal a large 300l thermal store with a secondary return? Internet search algorithms seem to have decided I don't need anything bigger than 250l! MTIA

Cheers for this. I don't used Facebook and I have a pathological allergy to any tech company which decides to outsource the hosting of a forum to somewhere else where they lose control over their data and access. Sorry, I am a bit of a Facebook activist ? Thanks to the API link from @James Newport I did actually find another link to a different user and developer forum Shelly has created to move activity away from Facebook, which is a positive move, it's here: https://www.shelly-support.eu/index.php?dashboard-en/ . I'll be putting some questions up there soon. I think that's very sensible. Shelly app partially redeemed itself for me the latter part of the weekend, but then on Monday/Tuesday started to go flaky again. It actually started to report humidity and temp readings from 2 sensors I'd disconnected and one I taken apart to look inside! I've just found out from the user forum that if the HT sensor is set to external power supply then it'll report every 10 minutes (well, I'll need to test this ?). My experience so far is that the usb powered unit works somewhat better than when it's battery powered and I suspect this is down to energy saving measures. I've found that if the unit goes offline, the usb unit reliably comes back online without a reset but the battery one sometimes needs resetting completely. Re the sleeping issue, there was a note on the forum link above that the HT sensor needs to sleep a lot to stop it from heating up. I've attached a photo where the manual claims that sensor reporting can be set to time intervals. I'll have to ask them where this has gone. It does seem, that as you say, I can only wake the device up physically using the button on the unit. I clearly misinterpreted the warning message I received. I don't. I've taken one of the units apart and think I've identified the humidity sensor on the board. It does look a bit like the sensor component used in some of the DHT22 internals where I've been able to find images, but really can't be sure (I've lost my large magnifying glass so i can't read any of the identifiers on the other compenents either). For my needs to have sensors sitting under the floor, I've now got in some pre wired and caged SHT30 and SHT31s. I'm fitting those into the under floor space and will connect them up to a Pi when I've got more time. This, I think, is the more robust, long term solution. @James Newport you were spot on with your initial assessment that the Shelly sensors probably weren't ideal for my intended use, but they were definitely worth a try for this. Meanwhile, I do have some other needs that they're going to be ideal for, especially heating and lighting control in my wife's garden office, so thanks for the heads up on these!

I have a formula for calculating permitted notching merely at the end of joists in one of my carpentry books. When I've used it, I've always been surprised by how little can be notched even over a short span. FWIW it actually makes me feel sick to see this kind of practise, which is just unacceptable. It really should be redone properly and I sincerely hope you get it resolved.

Just tought I'd post an update in case there's an interest here. Unfortunately, I've not experienced a great introduction to the Shelly stable of IoT ? I bought 3 of the humidity sensors plus a couple of other items from Shelly and received them during the week. Setup was flaky, requiring several attempts to get them online. Eventually I got them online and placed them in some test locations to see what happened. I wanted to test reporting frequency and wifi capability. 2 of the 3 reported mesasurement for up to about 8 hours, then went to sleep and I had no means of waking them up to change sensor settings or force a report. Then, during the night, they went offline. Interestingly, I had two units placed next to each other and the other unit carried on reporting back. When these units go offline, I could find no way of getting them back online without having to physical reset the units and go through the process of re-adding them to the app and home wifi network and then the cloud. This time it again took several attempts to do it successfully. I've also tried configuring the sensors through their own wifi access point, but they have a tendency to go to sleep while I'm either connecting to them or using the http interface. So now I've placed the sensors in other locations and for 24 hours they been running fine and report at fairly regular intervals. Unfortunately it seems that Shelly have updated the app/http interface and configuration access to the H & T units such that I'm not able to easily set a reporting frequency. In their manual, it shows this option and I wanted to have them report back on a 24 hour basis, but the app and http interface only allows me to set reporting based on temp and humidity change thresholds. The other thing I can't work out is how to wake the things up. When I've tried to change thresholds for temp and humidity the app tells me the sensor will update when it next wakes up or that I can do this manually within the app, but there is no option anywhere in the app or http interface where I can force this (that I've been able to find). I don't think it's the sensors themselves that are the problem, more that it's the app/interface and poor documentation available from Shelly. I can very much see what they're trying to achieve and maybe I just need a bit more time playing around to understand what's going on. I am somewhat wondering if there's a way to hardwire these using the pinout instead, or just going down the route of Raspberry Pi where I've got better access to support and assistance. Meanwhile, I was tempted by Shelly's other offerings so I am playing around with some other ideas - nothing like scope creep! Anyway, work in progress ?

Lots of mini cranes out there that could get in there and would be physically smaller than your 14m telehandler.

What @newhome says. The only part of building regs I.m aware that requires a bath to be installed and accessible on the same storey as the master bedroom is in M4(2). However this is an optional requirement that only applies if compliance is stipulated as a planning condition. So if you don't have a planning condition, the regs for accessibility are M4(1) which just says: Sanitary facilities WC facilities 1.17 To enable easy access to a WC, a dwelling should comply with all of the following. a. A room (which may be a WC/cloakroom or a bathroom) containing a WC is provided on the entrance storey or, where there are no habitable rooms on the entrance storey, on the principal storey or the entrance storey. b. There is clear space to access the WC in accordance with Diagram 1.3. c. Any basin is positioned to avoid impeding access. d. The door to the room opens outwards and has a clear opening width in accordance with Table 1.1. I've quoted the other sections below in case you're inclined to read: Part G says in G5 Bathrooms: A bathroom must be provided containing a wash basin and either a fixed bath or a shower. Scale of provision and layout in dwellings 5.6 Any dwelling (house or flat) must have at least one bathroom with a fixed bath or shower, and a washbasin. Scale of provision and layout in buildings with rooms for residential purposes 5.8 The number of fixed baths or showers and washbasins in buildings with rooms for residential purposes should be in accordance with BS 6465-1:2006 and A1:2009 Sanitary installations. Code of practice for the design of sanitary facilities and scales of provision of sanitary and associated appliances Building Regs for Access to and Use of Buildings Part M4(2) Optional requirement M4(2): Category 2 –Accessible and adaptable dwellings 2.18 The provisions of Section 2B apply only where a planning condition requires compliance with optional requirement M4(2) for accessible and adaptable dwellings (see paragraphs 0.3 to 0.6). WC facilities on the entrance storey 2.27 To provide step-free access to a WC that is suitable and convenient for some wheelchair users and, where reasonable, to make provision for showering, dwellings should comply with all of the following. C In a two or three storey dwelling with three or more bedrooms, the room with the WC and basin also provides an installed level access shower or a potential level access shower, and the shower, WC and basin (together with their associated clear access zones) meet the provisions of Diagram 2.5. Examples of compliant WC layouts are shown in Diagram 2. Bathrooms 2.29 To provide convenient access to a suitable bathroom, the dwelling should comply with all of the following. a.Every dwelling has a bathroom that contains a WC, a basin and a bath, that is located on the same floor as the double bedroom, described as the principal bedroom in paragraph 2.25b. b.The WC, basin and bath (together with their associated clear access zones) meet the provisions of Diagram 2.5. Examples of bathroom layouts are shown in Diagram 2.7. c.Provision for a potential level access shower is made within the bathroom if not provided elsewhere within the dwelling.

I'm guessing you're referring to 14m lift height not reach. Here's an example of the kind of size telehandler you'd need https://www.ardenthire.com/plant-hire/telehandlers-and-forklift-hire/jcb-535-140/ Beware, they are big machines so when you say rear extension, what is access and turning space like to lift your trusses? Ardent hire have a depot up north but I'm not sure if it's up north east enough for you? They do operator and unit or unit only but you would need a credit account with them first, this can take some time with lots of checks. I think they even did a credit check on me when I set up an account. Some hire places can add on insurance but it's quite expensive usually at something like 12% of hire cost, other wise you can buy short term hire insurance from the likes of https://www.jcbinsurance.com/ Looking at it differently, you might be better off simply hiring a crane for half a day or a full day, that would come with an operator and wouldn't need the manouvering around site of a telehandler. I wonder whether you'd benefit from posting some pictures of your site and posting a question here along the lines of how best to lift the trusses and see what suggestions come along? Loads of experience here with these sorts of problems. HTH

Indeed it is. From referencing, this figure appears to originate from a book by Richard Girling called Rubbish! Dirt on our Hands and Crisis Ahead. Originally published 2005 and then subsequent editions it seems. https://www.richardgirling.com/ It may be published a while ago, but it's interesting how long it takes for some figures to change. When I was at Uni studying energy and thermodynamics, power stations where maybe 15% efficient, take away grid inefficiencies, the figure which I can't remember was pretty bad. Despite developments, today I think the electricity grid has only made it up to about 40%, maybe nudging a bit more? I'm sure someone here can give the exact figure Anyway, it's gaining prominence due to the growing calls for urgent revision of the take-make-waste production and economic model that has been the default for far too long. For example How bad design is driving the ‘take-make-waste’ economy. That really is scary, even just on a small scale.

Sorry to jump in but if you're not already aware, my wife's regulations apply here. All dwellings must have at least one generous bath or more, otherwise it isn't habitable. These obviously supercede G5 which otherwise states either or. Unless I'm missing some other obscure regs...

I would look at this problem differently. First I'd suggest that the psychological aspect is more complex because if you look at the systems of product design, production, supply and then waste, it is very difficult for end users to do the right thing and that disposal isn't really the problem. LFT simply targets one small dimension of how we deal with waste at one point in the system, not the system of how we create and reuse waste. For example, the Cambridge Judge Business School quotes on its page on Circular Economy and Sustainability Strategy executive education that "90% of raw materials used in manufacturing in Europe become waste before the product leaves the factory" and "80% of products made in Europe get thrown away in the first six months of their existence." Both these quotes point to the larger problem of waste lying elsewhere in the system, and unless you look there, you're going to miss it and spend/waste loads of money on a pointless policy that doesn't produce the intended outcomes, even if it does produce a false belief that it has progessed things in the right direction. In construction, the waste situation is pretty horrific as the industry produces about 1/3 of the UK's annualwaste. The responsibility for waste management is often pushed down the chain to the contractor/builder to deal with, just as recycling seems to be pushed down to the individual consumer or end user company. Looking at it systemically is much better as it can push responsibility up the whole chain. Positive steps in this area include manufacturers of EPS insulation providing a waste collection service from building sites, although this isn't as well publicised as it should be and thus we still see loads of it chucked into skips. To me manufacturers must be held more to account for the products they make and how they make them to ensure they're not wasteful and the product is easily recycled/reused rather than expecting the client and contractor to deal with a product that's difficult to dispose of properly. For me, it's not just about correct disposal and making that easy for the end user, it's more important not creating the waste in the first place. LFT I think has done Sweet FA to deal with that ?

That's not what I'm suggesting, it's that we need to take a systemic approach to net zero, which considers the ramifications of the decisions and pathways chosen, so that we actually understand what damage, or benefit, might emerge as a result of those decisions and pathways. It may be more helpful for me to quote a document published by the Royal Academy of Engineering which highlights the importance of taking a systemic approach: "This helicopter view of decarbonisation of homes raises the wider sustainability and environmental impacts that result from a positive policy such as net zero, including: • Material resource related to mass production of components such as batteries and solar panels. • Circular economy, though the recycling and disposal of redundant components like gas boilers. • Biodiversity, which is significantly impacted by housing and infrastructure deployment strategies. While it does not necessarily provide simple or easy answers, understanding systems is vital for identifying all the trade-offs associated with decisions. It can help to identify potential leverage points, or points of influence that can be used to design effective, future-proofed policy interventions across this complex landscape." Yes, perhaps we are. In wider view, I'm referring to a systems perspective, encapsulated very well by the above quote, but also that it isn't all about just CO2 emissions. For example, the global company NovoNordisk recognises this by having an environmental strategy that not only targets the reduction of CO2 emissions, but also waste and resource use and they realise this makes perfect sense from both an environmental and business sense. They clearly recognise these things go hand in hand: "We consider use of resources, CO2 emission and waste to be our most material impacts on the environment across the value chain." This statement goes right back to my point. How can you reasonably ignore policy decisions that potentially have the opposite effect, or where you don't have sufficient knowledge to know whether it is actually going to provide that outcome? Because that is what you're doing here. What I'm highlighting is that whilst heat pumps are a great technology, their mass production may not be as universally benign as is popularly promoted, especially on forums like this. Given that you say the discussion is about CO2 and that the OP asks about the likely future of heating, gas boilers, in their context of CO2 emitters, absolutely fit in with the discussion as otherwise you remove part of the context of discussion. If the point as you say is about reducing CO2, then why is the baseline cost for day-to-day heating only relevant? You may have read about the recently published report on blue hydrogen, taking a life-cycle approach (as per the original paper I referenced), suggesting that blue hydrogen production may actually be more damaging in terms of global warming potential than burning methane in gas boilers. Interesting that this now starts to question the basis of the UK government's hydrogen strategy, due to taking a wider approach to understanding potential impacts of new technology. Now we're even seeing that research suggests methane may not be the 'second' most important GHG, but maybe the 1st most important due to its short term GHG potentency. My view is that narrow goals can often be counterproductive and may, particularly when dealing with large complex systems, reduce innovation, vision and flexibility. Narrow goals may also prevent both individuals and organisations from seeing or recognising other more valuable opportunities. The definition of net zero is really about finding a balance between output of emissions and sinking emissions. And it is clear from most of the formal definitions out there that one side of this equation is about capturing/storing/sinking CO2 that's too difficult to cut from emissions. The Carbon Trust, For example: ‘To reach a state of net zero emissions for companies implies two conditions: To achieve a scale of value-chain emission reductions consistent with the depth of abatement achieved in pathways that limit warming to 1.5°C with no or limited overshoot and; To neutralise the impact of any source of residual emissions that remains unfeasible to be eliminated by permanently removing an equivalent amount of atmospheric carbon dioxide. To risk being simplistic, but this may and already is in some spheres naturally focussing attention in that specific direction, one of those being the obsession with finding and developing carbon sinks so that the world can continue as it is and, like one Nobel winning economist suggested, GDP can continue to grow even with global warming up to 4 degrees C so not much to worry about. This represents probably the greatest risk - it may be possible to find technologies, but it's recently moved into the bizarre and rather concerning area of geoengineering where we actually have no idea of the potential ramifications of those activities were they to be conducted at the scale required. Thankful there are many people looking at it from a wider perspective, including more systemically, that may find solutions in other areas, not necessarily constrained by singular focus. As I quoted above, it is already recognised by those far more qualified and experienced than me that net zero policy does not necessarily cover "wider sustainability and environmental impact" and that it is essential these are baked into the mix, along with flexibility as insights and environmental effect emerge through the process. Drawing from the Royal Academy of Engineers paper again: "Challenges such as decarbonisation appear smaller and more manageable when broken down into constituent sectors and challenges. Without an over-arching system architecture or system transition strategy in place, there is a risk of failing to adequately account for the knockon effects that changes in one sector will have on each other. For example, transport decarbonisation strategies will make assumptions about, and have ramifications for, requirements for houses, workplaces, energy infrastructure and vice versa."

That is part of my point: that the net zero discussion tends to miss the wider environmental impact, often to the detriment of the environment and then requiring fundamental policy change at subsequent significant cost. Recent examples are European policy on diesel cars and current European (and UK) policy on biomass for energy and home heating (if haven't already read up on biomass use you will find that it is now causing net carbon emissions as opposed to its intended net carbon reduction and we haven't even seen critical mass yet). Each of these policies are based on a single narrow goal, as I believe 'net zero' is doing and I think it's a mistake. What I said: Indeed, but I didn't use the figures in that study as examples of Global Warming Potential, instead I clearly acknowledged this has changed in the last 10 years. Again, exactly my point which is about taking a wider view to really understand the environmental impact of technologies being proposed. That is why I used this study as a mere example. Who says? The production and processing of raw materials creates vast emissions, and also wider environmental damage. And if we decide to use technologies on a large scale that demand ever more raw materials and their processing, this will have a direct impact on emissions, but then it's even worse because those emissions come from areas that are much harder to decarbonise due to their energy intensity. I believe Herman Scheer covered this in his book A Solar Manifesto back in the 1990s. Generally, I think you may have missed my point(s) ?