SimonD

Thanks, there were two options, one which connected back into Raspberry Pi, the other came with drivers for Windows so I could download data onto my pc at certain intervals. Since my post, I found the original recommended sensor but it's only available from the US and pretty expensive. Hmm, I like the look of the Shelly sensor, thanks for that. Easier than everything else I've seen so far and actually not a bad price. The usb powered version I reckon from the specs is worth a punt as it should be able to cope with the prevailing underfloor environment!

My point is that there are trade-offs and no easy answers whatever technologies we decide to employ to reach some kind of suitable environmental balance (I'm personally cautious about using the tired net-zero phrase here. I think it's problematic because in a lot of environmental science, the term 'environmental impact' has come to mean only a consideration of greenhouse gas and/or global warming potential, but our use of resources has many other consequences that unfortunately get ignored - until it comes back and bites us further down the road). It's very easy to be dudious about statements without backup figures and one of the real problems we face is a lack of transparency so it's almost impossible to make a fully informed decision beyond some headline figures, or a simplistic single goal. Whilst on an individual level, a heat pump using, for instance (see this example study for figures), almost 10 times the amount of copper (40kg v 3kg), twice the amount of other metals, including aluminium and steel, almost 3 times the energy derived from natural gas (ca. 1400MJ v just under 500MJ), and nearly 2x the amount of electricity (504MJ v 294MJ), may not seem like much, as soon as you multiply that by lets say a rough 1.5 million units a year in the UK, not including the rest of the world, then you potentially end up with consequent issues elsewhere in the eco system. Regarding the greening of the grid, yes it has made significant steps, but just as with EVs, its a mistake to simply look at point of use figures because there is still a significant proportion of the heat pump efficiency that merely makes up for the inefficiencies of the grid. But again knowledge an understanding of this is lacking, even in some circles where, in my view, people should know better, they simply brush it off as irrelevant to the overall goal. Sometimes they even go as far as to allude to renewable energy being free so we should just build massive over capacity - yet this ignores the energy and environmental cost of the infrastructure and activity required to build and maintain the over-capacity. Much of this simply goes back to the principle that we should first be reducing consumption and improving efficiencies, then looking at what remains to deal with using technologies. This would ultimately be the most environmentally friendly way to do it, surely?

It's partly to do the the use of refrigerants as this does have high ozone depletion potential as the refrigerants do leak during both manufacture and use and need to be safely disposed of at the end of their life. However the development of CO2 as a refrigerant is a good thing here. Overall it's more in terms of the whole life cycle impact being more complex for heat pumps than gas boilers, which rightly includes the environmental impact of UFH systems, for example. Total figures come from the raw materials, energy and wastage associated with the life of the pump including for instance: 1. Extraction and processing of raw materials 2. manufacturing of pump components and assembly 3. installation 4. operation 5. UFH system manufacturing and contruction 6. Fuel extraction and processing for electricity generation 7. generation of electricity 8. transmission and distribution of energy 9. decommissioning - recycling and disposal of heat pump and related installations The electricity generation side has changed significantly in the last 10 years which has resulted in most of the CO2 benefits of heat pumps coming into play in the UK. In other countries that have relied on a better input of renewable energy (e.g. Sweden) the figures are a bit different. But even so, the true nature of the global warming benefits of heat pumps is still more complicated than often assumed (e.g. electricity is more efficient so therefore it's the best option type assumption) - John Cantor has a good blog post about this - Heat Pump global warming effects The figures for these are changing all the time so I wouldn't be surprised to see different conclusions on environmental impacts over the next 10 years. It's all shifting ground.

Sorry, have to laugh as I've been catching up with this thread and almost said exactly the same thing starting with 'the elephant in the room' ? But I do agree, it's fundamentally about 1st reducing energy consumption, making homes more energy efficient, and then looking at the appropriate solution for heating and DHW. A while back I read a research paper comparing carbon emissions for passivhaus retrofit upgrade and demolition/new build passivhaus and the conclusion was retrofit favourable (obviously depending on overall context).

In 2019 there were approximately 1 heat pumps installed for every 120 gas boilers installed new. This was about 1.2 million gas boilers, a number that is increasing every year. 2020 may have been 1.5 million gas boilers. Heat pump installations have grown in number, but the latest figures I saw reckoned heat pumps made up maybe 1% of total new heating installations. This is a sorry situation indeed given how mature the heat pump market is and it's a testament to how useless UK government policy is on affecting a necessary change. There is also the problem that just as with gas, there don't seem to be enough installers qualified to do the number of installs of heat pumps necessary. It depends entirely on your location. Round us, we can't get a green electricity tariff below about 18.5p. Ours, which I know is properly green (i.e. zero traded certificates) is just over 20p. We have a 'green' gas tariff of 4.26p. Last year when I did my full calculation I needed a COP in excess of 5 to make financial sense in terms of running costs. For me the argument for/against heat pumps just needs to be a bit more nuanced as it's all about balance, compromise and context. For example, the overall environmental impact, calculated to consider wider impacts than just CO2 is worse for heat pumps than for gas boilers. If you only take into consideration CO2 it's a different kettle of fish. Interestingly there's been a recent paper looking at methane emissions, essentially saying that the primary short term goal re global warming should be to minimise methane emissions, especially from disused oil and gas fields, farming, waste, and other industries and that it would make sense to burn this. This is obviously contentious right now. Heat pumps do work and they're an amazing technology, but they do have some fundamental drawbacks (compared to a narrow view of current heating demands) that need to be understood, recognised and compensated for accordingly. Likewise gas boilers could be far more environmentally friendly than they are currently (e.g. using green gas). The elephant in the room as always is that if you want to cut emissions, it's actually far 'easier' to do it by reducing consumption than by trying the generate the necessary energy by alternate means, which means as most have already said, upgrading housing stock. But unfortunately, as can be seen in the recent proposed policies by this government, they want to avoid this, searching (hoping?) instead for silver bullet technology. They also have in place many policies that prevent, and/or increase the cost of retrofit upgrades, and the full utilisation of renewable energy. For me, heat pumps are only a part of the total solution to the problems we face.

I'm genuinely interested in humidity sensors for data logging . I'd like to install some underneath my new suspended timber floor - to sit there in perpetuity. Supplier I was recommended no longer supply them and I don't even have a brand name to search. Can you recommend any for me to look at?

Welcome Des, a very topical subject. Beware that you have now opened a whole can of worms! ? Just to start with a couple of questions: are you viewing the climate change issue merely from the perspective of greenhouse gas, CO2 in particular, or also wider environmental impact? And which home in particular is the heat pump most viable? Causes some rather heated debates, and not just on this forum. ? Good luck with it.

Thanks, it's handy to know. It would be so helpful if the information was easily available on their website ?

Nice one, thanks, even better price at nearly half local suppliers.

Found it, thanks. Link published courtesy of @MortarThePoint on this thread https://forum.buildhub.org.uk/topic/21504-partitions-timbers-studs-vs-metal-c-studs/page/2/ Very interesting. Looks like my initial sketched estimates for staggered stud wall with resilient bars are not far off, just looks like I'll need to double up with acoustic plasterboard each side for what the Canadians show and refer to as a possible STC 60 - 62. Then look at any low frequencies. I'm aware of the lower frequency issue. It would be much more helpful if manufacturers could give Rw + Ctr figures to account for how the buildup deals with low frequency sounds as well instead of just Rw. Do I assume correctly that by noise of the rest of the construction, you're referring to the room acoustics as opposed to transmitted noise? If so, it's always been beyond me to understand how some focus is put into dealing with noise transmission through walls and floors and nothing is done about the acoustics in the room. For me, the first priority is to deal with room acoustics, then transmission. If I can successfully deal with the room noise, the walls will have less work to do and the rooms will all be more comfortable. I'm always flabbergasted by the number of expensive develoments I've visited to find that noise in some rooms can become deafening with only a few people in there, especially kitchen/dinners. I haven't done any acoustics work for almost 13 years and realised all my old reference books on the subject are right at the back of the storage unit, so hoping that I might be able to find the up to date info I need online now ?

It does seem to be the goto. That's an amazing price you got there for the slabs, I can't get anywhere close to that locally. Can you add me to your account??? - about 175m2 of 100mil slabs would do me fine for the rest of the house ??

Always difficult to know exactly what product they might have used. Both the Lynvale and Xpanda tapes have BBA certs with expected lifespan equal to that of Compriband. They're also not exactly cheap alternatives.

Thanks, yes, I totally agree that the complete construction plays the major role, but in terms of the mineral wool, I do need to understand its response across frequencies. Some of Rockwool's commercial range shows a remarkable performance at fairly thin thickness at only 50mm, but it's a resin bound mineral wool board, whereas the domestic product looks to be inferior. It's also interesting to note that the practical absorption coefficient for some mineral wool reduces at some frequencies even with greater thickness, so the rule about thickness doesn't always hold. But all of the mineral wool products do tend to perform best at 1k hertz upwards. The sheeps wool product does have the certificated test data for building regs part E compliance. For this particular instance in the wall I'm starting by looking at using a staggered timber stud wall with resilient bar, extent of plasterboard to be determined once I know the most troublesome frequencies for the room in question. I may go double stud if necessary. Intermediate floor wise I'll have a resilient layer on top of subfloor, acoustic insulation between joists, a timber resilient layer of 50mm, which can be filled with insulation and I also have the floor height to add an additional resilient bar prior to plasterboard - not quite enough for a suspended ceiling. Inside, the room will have acoustic absorption measures. I have some very specific requirements to adhere to with this one ? One word..headache..for me that is..

I've been scrabbling around to find sound reduction index charts for both Rockwool acoustic insulation slabs and Knauf acoustic roll. The only manufacture I've so far found that makes easy access of this info is Thermafleece although I've found some for Rockwool commercial products. I've emailed tech support for both companies but wondered if anyone here might have the data to hand as I need to make some initial calcs for a wall and ceiling buildup. Ta

Yes, I have used loads of the 15mm wide 5-12 from this company. I've also used other thicknesses up to 25mm. It all works fine. I've more recently used Xpanda tapes as this was slightly better financially and still bba. Can't really tell the difference other than slight variation in colour - one darker grey than the other.

Those pin holes are a very strange thing indeed. Re the distributor and RK39, I'd have one question to ask and that is how much experience the distributor has specifically working with wood fibre. RK39 is designed for thicker application on masonry substrates and wood fibre behaves very differently, so it's not just about the waterproofing aspect. Is it designed to bond with the wood and does it have modifiers to make it lighter, for example (RK39 at recommended thickness is nearly double the weight of thin coat)? Baumit StarContact is the adhesive/basecoat used in Baumit's ewi systems. If the distributor the plasterer has spoken to can reference lots of work with wood fibre, I mean years of experience and can show this render works over the long term, then fine. Otherwise treat the opinion with great care. The reason I'm saying this is that I've spent over 3 years talking to people and researching woodfibre ewi and found out that there are a lot of people (including reputable suppliers) in the UK that pretend to know what they're talking about regarding suitable render on wood fibre - there's also a hell of a lot of random detailing approaches which are insufficient. In this time I've been recommended everything from lime putty to hydraulic lime to other weird and wonderful solutions, even using hemp fibre in the basecoat instead of mesh. There is, unfortunately, a lot of bs out there that stems from a lack of experience and knowledge about the product. It even goes down to the basics that suppliers and installers often don't even know they've got to measure the moisture content of the wood prior to render application. In the end, thanks to a Baumit distributor putting me in touch with them, I ended up speaking to someone who has years of experience working with the material on the European continent and they understood the product much better. Lime Green is one company who also have a good understanding and their hydraulic lime render for wood fibre has been modified to work with wood fibre. Sorry to bang on in what might seem a negative way, but I remain dubious about the opinion RK39 should be fine. As a side note, the guy I spoke to with loads of experience in the field suggested I add a cavity and install render board outside the wood fibre explaining that this is a safer approach in this country. If I'd known that when I was building my structure, I would have modified my designs accordingly. Unfortunately, like you I seem to be stuck with the direct render and will have to see if it lasts.

RK39 is a cement free render - lime only.It also doesn't have fibre reinforcement. Be careful here as lime only render may not be suitable for application onto wood fibre even if it has added modifiers (I've discussed this very topic with lime render manufacturers technical departments and there are multiple reasons why - thermal shock, moisture management etc.). The required thickness is also different as the base coat and topcoat on RK39 for external use is minimum 13mm, probably 15mm. The thin coat is only 9mm. Big difference in weight. Why has your plasteres decided on this change of product? Has he actually gained technical advice directly from Baumit? If you're dubious about MC55W, I'd question whether RK39 is a suitable alternative. You might be better off looking at the European technical assessment documents for Pavatex and see which alternative thin coat renders are available. For mine I also had a choice of using certain Weber products. Edit: If you're after a lime only render from a different manufacture, then Lime Green sell one suitable for woodfibre (although primarily developed for their woodfibre ewi system) - it's quite expensive, mind you.

I've done the same, works really well mix and match. I use it a lot for diagonally bracing the transom sides of the scaffold, especially when building higher towers or when using the narrower 3 board transoms. Also handy to create a lifting point for winches.

Kwikstage. Price will ultimately depend on the configuration.

Great clarification by @Gus Potter. I had similar trouble with my architect & structural engineer, even though the architect introduced us to the SE. I thought things were strange when my architect phoned me up to ask if I could ask the SE some questions re the design. SE was terrible at responding to anything or communicating so sacked him (so was the architect and I dropped him later on). I brought in another SE who relied on architect's slightly more detailed planning drawings for the structural scheme. Neither communicated with each other so I picked up the phone and told them in no uncertain terms that we needed a pow wow. Banging some heads together softly over coffee and a spread of drawings on the dining table worked wonders and we were able to proceed, all in good terms. I'd pick up the phone, explaining to the professionals something along the lines that as their client it would be really helpful to have a structural design and drawings that fit together to enable you to build the house and if they could facilitate this you'd be forever grateful. It may help to remind them what needs to be done ? Just saying professionals in this field rather often seem to need reminding that client service is integral to their role ?

To follow on from what's already been said, what are the sizes of your windows? You can definitely do them yourself but to risk repeating what's already been said, there are two mains questions to consider: Do you have the machinery/equipment/manpower to take delivery, unload and lift the windows into place or are you willing to get it in and use it? Do you know how to detail the window installation and are you willing to spend the time to learn? I've done it twice. The first time they were standard sized windows in a renovation. The delivery driver kindly helped me unload, sharing the carrying to the back of the house. The carpenter I used and I could easily lift the windows into place. Easy. The second time I had to hire in a telehandler for offloading nearly 2t of windows and doors, and lift 3g windows up to 200kg and 2.5 x 2.6m using hired in specialist glass lifting equipment. Luckily on the 2nd the manufacturer provided me with all the detailing information necessary for self install. Machinery and equipment hire/purchase cost me about £1k and I've definintely spent a few hundred on the airtightness/sealing/fitting tapes, sealants, foams, spacers and flashings needed. It also took me a long time to finish it! As for warranty risk, it really depends on whether I've followed the detailing instructions correctly or not. If you're lifting any especially heavy or large pieces, you'll need to think hard about your lifting plan - this was the most challenging aspect of my 2nd fitting. 2nd time was a right headache and fraught with high stakes risk! It scared the hell out of me, but got done in the end without any mishap.

Hmmm, GBS wanted about £8k to install mine! I know this company has a great reputation but I went elsewhere as my experience of finalising an order was very underwhelming and they seemed disinterested in my custom.

If you can, wait until autumn to install those board on boards. You'll get less problems with the heat and sun and give the timber time to aclimatise over the winter and spring. In terms of the cracks, you're better off looking at an exterior wood filler, like Liberon Wood Filler HTH

Yes you can. The detailing obviously needs to change somewhat as you need to fix the battens through the wood fibre into the timber frame/masonry wall. Having a rainscreen outside the wood fibre insulation is recommended now in several parts of Europe to protect against wind-driven rain. I have to say, next time I use wood fibre I would swap out the direct thin coat render for a rain screen. Much better insurance long term, I believe. HTH.

I've got a few glulam lintels but my construction is hybrid masonry and timber so not entirely encased in masonry, just sitting on it. I designed the lintels to be visible. There are a few places that will sell you beams cut to length. With the company I used I just sent them details of the openings together with drawings and asked them for equivalent glulam, it was no problem design wise. However, they were more expensive that steel lintels and a lot more expensive than concrete ones. Span wise mine are about 2.5m.