FM2015

If the fake VW data was used to formulate an average, yes, the average would be wrong. LCA is a useful but wholly imprecise once above a certain level of detail.

That report is full of good information. And yes, the eurocode sets out an ideal lifespan of 50yrs but the lifespan of some significant individual elements is less. Which means in the UK, houses are being cleared that are between 17 and 30 yrs old. Which is bonkers! Using that data rather than the aspirational eurocode, might be a more appropriate for the UK. European construction methods and inputs vary greatly just like the results.

Life cycle assessment of buildings uses a design life which in most studies is standard; 25yrs. The mass builders effectively build the same house, cheaply, multiple times in the same plot. Stick build and bespoke framing using premium timber are two different things. Plenty of 300+ yr old timber frame houses about but the materials are very highly priced. As a self builder, it becomes a matter of choice and budget, and that potentially 300yr old timber framed building will cost more than some alternatives for no additional benefits. You said stick build was best, based on LCA. I would disagree.

Without wanting to open what is a massive can of worms, please show me where stick build has a better life cycle assessment than anything else. In most cases, LCAs are dependent on time and for some reason, houses are generally linked to a generation, i.e. 25yrs. Over 25yrs, there is some scope for your statement to be true. After that, most stick builds start to fail, allowing the mass builders to buy the land, knock down the house they've already been paid to build and get paid to build another. Not only is that the worst con going but it's obsolescence by design masked by LCA. If you build a house that will last 100+yrs, your LCA will demonstrate that the Carbon embodiment and footprint associated with the build are miniscule when compared with the buildings use over the extended life. So, unless you spend an inordinate amount of money on sourcing decent timber, not sticks, force grown for profit not the environment, wood is not the way to go.

I'm not sure what others have experienced but although we know that concrete of a certain spec and width should be impervious to water HOWEVER I've not met a a warranty company that would accept it as a waterproofing method. Additive isn't necessarily the answer as discussed in several places previously.

@NickK, sorry, thats based on supply and install experience. Block per M2 might be less expensive but more labour. I am a contractor so I see it from a different perspective. To be honest, we stay clear of the systems you have to assemble on site but that is just us.

Some would say r wall is a more difficult product to install with no experience. Polarwall, of which r wall is a clone, would be the same. We have found r wall to be the upper end of the price bracket but it depends on where you are and who's installing it.

All rates for follow on trades will be the same irrespective of shell type. A lot of very broad brush assumptions.

Coming at this from a contractor perspective, to get the same stage and performance values, we generally came in more expensive than timber frame and on par with masonry subject to geographic area. That is for supply and fit. If you had three houses, one of each build type of which there others but we'll ignore those for a minute, and you ordered all three on the same day, the masonry one would most likely start first and finish last, the ICF one would start second and finish first and the timber frame, in current market conditions, start last and finish second. Note: accounting for lead times. One school of thought might be that a "superior" end product shouldn't cost less than a lesser alternative. Wastage is a product of design and inefficiency. With polystyrene ICFs there should be very little wastage, a couple of dumpy bags maximum. A lot of ICFs can produce all sorts of savings throughout the build. As a contractor again, it's our responsibility to share these benefits with follow on trades. If you self build, be involved, understand the product and extract practical(!) Information from the supplier. And think three steps ahead before you make that cut! And don't cut corners, figuratively or literally!

Some will probably shoot me down on this but I'd say most EPS ICFs will work with products from https://www.matclad.co.uk/product-category/brick-slips/ They are not ugly! And can make slips from your choice of bricks. Not sure what that costs though.

In a good way or a bad way? The company I work for undertakes ICF shells on a fixed fee basis and because of the market, delivering on schedule is the only way to be profitable. Day rate might seem a good option but all delays will be paid for, rain days, material wastage, broken plant etc etc. A well specified job for us is a dream to work on, it's our responsibility to minimise wastage, supply the kit, wear a wetsuit and the build quality. We take those risks on. I think that if you are in a hurry, picking some major phases to be undertaken by contractors could save you money in the long run. If time isn't a factor, take it on yourself. And only day rate trusted, referenced individuals. A block layer on £2 per block can earn £300+ per day or be on day rate, £150, and take twice as long. Same amount of money but how much is the time worth to you? Blockies around me do day rate in winter and price in summer....they're not daft!

Or any other build system that can give you a fixed cost for the same thing which meets the budget ?

@nod that's good going but difficult to reproduce everywhere and without a very good network. If you're borrowing money, time is a serious factor. Interest payments and time between draw downs can make a huge difference to your bottom line. The guys who we come across that are on site a stupid amount of time and involved throughout, every screw, do get the "best" return providing the admin is done. Others, seem to like a particular phase but then lose interest, change the plan, tinker without being immediately useful, see their budget creep. A personal shocker is spotlights. We fitted 185 downlights in a place, the specified lights were £50 ish each. He'll of a lot to spend on downlights versus a pendant or lower "quality" downlight.

Hahahaha, if only this was as easy to do as say!

BBA is a funny one. Some warranty providers insist that everything covered by their warranty has BBA others don't. Plenty of ICFs have BBA but all have some sort of third party certification. To show how disjointed the process is, take jackon thermomur. Its been used quite a lot over the last few years and its use is increasing. Only got it's BBA accreditation in October 2020 and the accreditation only covers above dpc walls. Nearly every build we have been involved with that uses jackon has a basement. All those basements are still covered by a third party warranty. I posed the question to a group of architects and engineers and their response wasn't too surprising; it's a high level way of presenting risk to insurers. If all products have BBA, it means that all insurers, are appraising the same risks. Just because we have left the EU, some providers still recognise EU accreditors, which is just how it was a year ago. A bit shocked by your quotes....past experience would have had durisol at the lower end. Timber is shooting up in price though with pressure on supply and demand which might be a factor.

Sorry John. I didn't mean to offend. To be clear on our process, we fill 1m and then move on around the building. Ideally and depending on concrete, we leave an hour before we put another metre in the same place and so on. In a gable, that last metre could be going on top of concrete that's been in place of 6hrs. From a budget perspective, doing this can save labour and is a more economical use of the pump. If the building is below a certain linear meterage, then it won't be possible, above, then it might. Case by case judgement based on experience. Pretty sure most ICF suppliers don't warranty the installers. We all stretch things and it's no different from using a wood saw to cut plastic pipe. Your previous comments about reinventing the wheel are so apt here. I work with ICF every day and am forever finding or seeing different ways to achieve the same. The reason for this is no standardised rule book and necessity becomes the mother of invention. Forum like this one pools that knowledge be it from a self build experience or a professional experience. The individual using the information is still the critical factor.

Regularly EPS pour walls at 3m and 5m is the company record but that was professionally scary. A gable end on a single storey build. We were a bit greedy really, caution should have prevailed but the concrete was good and the build big enough that we felt it worth a go. All went fine, pokered. Four main causes of blowouts: wet concrete, poor prep, rushing and poking.

I live in one and have built several and in my opinion, for that's all that it is, I can't reconcile the expense in the general marketplace. If it's what you want, have it. The point that I was trying to make was that how a building is used is very significant and a well built, super efficient (on paper) building will not super efficient if it isn't fit for purpose. That purpose is to serve the occupants. As a terrible example, I'm sat here with a jumper on, the heating off and the patio door open. . Inside, the temperature is about 14 degrees. None of the expensive stuff is working, I'm not cold so it was all a waste of money. I didn't consider how I would use the property. Someone else will be diametrically different. I specced the house for them when I should have saved the money for other things like a better kitchen. I don't just build one offs so when dealing with problem of affordable homes and passive standards, a qualitative and quantitative assessment is made and the life cycle assessment suggests passive standards are really just there to mask over an industry that hasn't given two hoots for the environment. The average person won't realise the benefits. Once again, just my opinion and I'm happy to be convinced on another way.

One of the reasons woodcrete requires less bracing is because of the mass of what you are trying to contain. A lot of poly versions are mass pours to create a solid wall. Woodcrete tends to form a lattice work of columns with some horizontals. Lintels therefore generally need extra bracing to take the weight and maintain shape. Poly bracing should be costing about £5 per set per week, so an average house (40 props) £200 per week.a two storey house, say 5wks, £1000. Those props will give you internal access platforms to plate height meaning you don't need external scaffold until several weeks into the build. This should give a net saving. Theres no option readily available to provide this saving with woodcrete. Concrete quality is a fair point. Too wet and you will have problems either in pouring or consolidation. Specification to the concrete company is key and if it's outside of spec, send it back. Hard for the uninitiated and they will shout but if you buy a burger from a well know brand and it's not what your ordered, you'd send it back. U values and passive house standards are well intentioned but widely miss the mark in my opinion. There are few systems which perform in the real world. And is it worth the extra money? In order to achieve payback in a reasonable time frame, for passive standard housing, you can never open a window. That ruins the science experiment. There are plenty of cost effective solutions for building that fall short of aspirational standards but when combined with super efficient appliances and sensible behaviour changes, the building will perform very well. This is why we advise people to really understand what they are trying achieve. 6" of EPS on the outside of the wall is a gross waste of materials but from a life cycle assessment perspective, the occupier's behaviour is more significant. U values are just a way of comparing products in a standardised way but requires a significant number of assumptions and is only one method of comparison. It is highlighting strengths and weaknesses from one perspective. It's not the only perspective. For example, a mass poured poly ICF is pretty much two materials throughout; concrete and EPS/XPS. Woodcrete has three materials but they don't all exist everywhere. Does their u value apply to the wood only bit or the bit with wood, pir board and concrete or is it some sort of average? My point is your comparing apples with oranges. Both fruit, both good for you but totally different.

Andyh, If you have a decent, thorough SAP assessor, he should be able to demonstrate how little actual realisable benefit you get from extra EPS on mass poured walls. Wind chill is more significant for example. That's why the general rule across all EPS products was, until more recently, 2-3". A lot of EPS blocks have a fixing point which gets further away from the surface if you add EPS. This can impact on any external fitments. Extra EPS on the outside helps maintain steady core temperature but like I said, realisable benefit? To be convinced in a real world situation.

You've not heard about the plumber driving his van and it caught fire? The quickfire blow torch got trapped, trigger pulled, gas still attached. Always disconnect your cannisters! But not with foam!! Foam gun cleaner is a bit of a misnomer. We find it ruins more guns than it helps. Best just to keep it clean and keep a can connected.

Totally open. I've never used woodcrete and my opinion is based on what I've read in the most part. My site experience is limited to a few days on a site pouring concrete and providing some kit. It was a big site and hats off to the distributor who bagged the job. The whole woodcrete process and to some extent the science of how it performs was totally alien to what I was used to. I did a bit of research and came to a decision that I prefer the EPS options and have stuck with it. Not that they a without issue!!! Some blockies won't touch timber frame. There is a skillset difference but some just put their eggs in one basket. Probably bite me at some point! I've had conversations with the guys at Passive Purple. They do all kinds of spray membranes and I'm curious to see it used first hand in any form of ICF. They're YouTube channel is good viewing, not sure I'd do that to my Audi!

Nice starter for ten! With regard to woodcrete, I'm not convinced it is the best system for our climate, waterproofing and making airtight are two areas which give me those concerns. HOWEVER I'm pretty convinced that they can be achieved. I am a fan of the spray membranes. If they are as effective as they claim, the application is more tolerant of lesser quality installation. IE a competent self builder can apply with a better success rate than some of the traditional membranes.

Hi all, I got reading the forum over Christmas and am finally saying "hello" after six weeks of voyeurism. I can't hide from the fact that I am a long time ICF proponent and having been installing mostly one brand over the last 6/7 years. It's all the company I work for does; ICF shells from ground to weather tight. I'm here for two reasons. The first is actually to provide a bit of support, expertise, terrible anecdotes in order to even out the playing field between self builders and the world of ICF obfuscation. Second, if I make some contacts, expand the network, raise the profile, I'd rather do that here than on LinkedIn. Hopefully this is okay with everyone. Will gladly take any advice on content should Mr Undiplomatic wades in. Cheers, Dom