MikeSharp01

No PVC nearby - mostly it will be clamped between / under wood to provide thermal breaks. I have used gorilla glue on XPS in the past, works OK.

We have a few places where we need to get some cold bridges around windows dealt with and it looks to me like STYROFOAM™ will do it. It is XPS has a compressive strength of around 30T / m2, a good U value at 0.033, is very workable, and is not expensive if brought as sheets. Any opinions / thoughts / experience anyone?

Small minded approach really - they will get blown out of the water by stuff you can get in Lidl as the whole thing becomes bolt on and Alexa takes control. Why would you bother with a dimmer block when you can shout at the bulb and tell it how bright you want it, what colour temperature you want, how long you want it on .....

Don't forget that the Architect may also be needed to tackle the Building Control Drawing aspects - which will be extra. They have a standard pattern of phases so you should be able to work out with them how it all works. If you are building a traditional style house then you may find you don't need an architect but once to go a bit out of the ordinary I think it is worth it. We looked at several architects, boiling it down to a shortlist of three and then we interviewed each after first giving them the broad spec, somewhat like the one you set out above but including budget and with a mood board - several pages of things we liked in terms of aesthetics etc. This worked for us, we chose one in the end and it worked out well I think. Three meetings is not too bad, you can do a lot in those meetings provided you give them a good idea of your desires before you start. Total architects bill up to BC was around £13K (2016), ours is only 156m2 so a bit smaller than yours. They often (maybe always not sure) try to link the fee to the build cost so we worked with them to engineer that as because we are doing a lot ourselves the build cost was projected to be quite low on an m2 basis (about £1250).

You don't use the @ in creating PM address just type rob99, or whatever name, and all will be well I think.

I think @A_L means that the new wall value if using PIR will be but if there are any changes to the geometry it could be different. I just tried it on PHPP and got 0.229 for the Frametherm and 0.157 for the PIR so that agrees with @A_Ls figures. PS Also do not forget the hydrothermal (moisture migration) changes going from Frametherm to PIR will make and those figures are the U value for just the insulation not the whole wall buildup so the wall value will be less, assuming the whole wall is not just PIR .

Indeed

welcome - ask away but we cannot guarantee there will be no silly answers, in fact we can guarantee there will be.

I think the problem is that the vertical battens are cantilevered from the I-Joists the insulation is not structural so the fixings have to; 1. support the weight of the cladding 40mm off the I joist (80mm & 60mm in some places) and 2. resist any wind pressure pulling the cladding away from (out of) the wall. The weight is about 24Kg / M2 (Each batten supports about 3m2) so not massive but the wind load is an important factor.

We are having the devils own job getting a secure fix for our external cladding. It is essentially tile hung, same tiles as roof and there the vertical (31 deg) battens are fixed to the inner I-joist flanges with twist nails, as per the manufacturers details - no problem. They don't have details for doing the same thing when the construction goes vertical (they have told me this) a competitor may have a detail but they are taking an age to get back to me. I have looked at cladding type brackets but these are designed for cladding systems, generally frames that support cladding panels, rather than vertical battens that then support the horizontal tile battens. The insulation thickness on the outside is 40mm for the most part but 80 and 60 in places. The main insulation is the 300mm between the I-Joists. Does anybody have an clever ideas of how to do this?

Very true and the research you cite highlights this and it also has some depths that might need investigating if you are going ahead with MVHR on a bigger scale than the Cardiff models. The research did two things:1st it modelled both houses using the PHPP (2004) so turning off the MVHR naturally results in lower energy use because the MVHR is not running and / or the running of the MVHR did not recover enough heat to 'pay' for the energy required to run the MVHR. However the paper does point out that the MVHR was more efficient when the temperature throughout the house was kept constant. There is a lot in there about the 'comfort temperature' so to some extent the energy model shows that if you are both happy to widen the comfort band and you live in the South West you can have a lower energy bill without MVHR I don't have time to work out what the 'breakeven latitude' is but there must be one if only notional as other things - coastal area etc must come into play. 2nd it looked at the real figures from the two houses and found that the real consumption for the MVHR house was almost as predicted while that for the non MVHR was significantly lower. The paper looks at this and finds that some of the difference was the lower running temperature of the home and makes an adjustment which brings it up but nothing like to the model level. The paper, to my recollection makes no attempt to explain this much further although the point very much stands - it was lower. However in its conclusions it makes one point that was the cruncher, and you highlight it above, for me and the was that "Devising systems that ensure occupants open and close ventilation opening at suitable intervals to provide adequate fresh air is critical and might constitute an advanced model of trickle vent, automatic opening and closing mechanisms, new window designs or other manual or automatic systems." (Sassi, P. (2013) A Natural Ventilation Alternative to the Passivhaus Standard for a Mild Maritime Climate, Buildings, MDPI AG, 3(1), pp. 61–78, [online] Available at: http://dx.doi.org/10.3390/buildings3010061.) The winning factors for us in installing MVHR are summed up as; MVHR in the age of intelligent buildings - which can turn the MVHR off when not needed, can sense the RH around the place and act accordingly, recovers what would otherwise be waste heat when this is valuable (worth it) and needs no supreme intelligence in the occupants - that would be me in my old age, is the way to go.

Not sure the building physics is being understood here - ventilation, any sort, is just that, fresh air in stale air out. Without ventilation the stale air builds up and because quite a lot of what we humans do creates moisture, from perspiring through cooking to showering etc, that will build up as well. Moisture is not good for building fabric but is the stuff of life for mold etc. So while trickle vents, or poor air tightness by another name if you think about it - same for MVHR but then with a conservation purpose, do work at keeping the air fresh they are not dynamic. So cannot cope with changes in air quality as MVHR does through the use of humidity sensors and boost modes, do nothing to filter dust / particulates and because they don't recover any heat they do nothing for energy conservation. If you have a well ventilated house with no trickle vents air tightness cannot be high because the BRs call for so many air changes unless of course the house is non compliant! Air tightness is not a ventilation standard although you are effectively treating it as such without trickle vents. Having said that a UK BR house is allowed 1x20p piece in every square meter of fabric for air tightness, IE not very air tight - imagine driving along in your car with several 20p sized holes at 30mph, a passive house allows 1x5p piece every 5 square meters IE a lot more air tight. (You can see a neat graphic of this on page 5 of this BRE document. https://www.passivhaustrust.org.uk/UserFiles/File/Technical Papers/BRE_Passivhaus_Airtightness_Guide.pdf )

If you are talking energy performance then it is but it's also about optimising (maximising perhaps not so much) everything including the glazed area, N-S-E-W etc, because air tightness alone won't work without good insulation and insulation is reduced by poor glazing options. Triple glazing is getting much more common because the innovators & early adopters have bundled in so with early majority starting to join in now the price will drop further thus making it more likely that the late majority and laggards will get aboard as well. By which time other options will be more expensive and so not adopted unless for conservation reasons. When I first took my mobile phone into work in late 1986 my colleagues all laughed at me and said it would never catch on!

The technical challenge with bifolds is air tightness. I think you will need to spend big to get good air tightness in bifolds.

Its not about energy prices its about the damage to the planet - with luck the groundswell will force it.

Given the rate of adoption of electric cars, and the fact there will be no choice in about 10 years I cannot help thinking it wont be long before HMG see the writing on the far to poorly insulated walls about where all the carbon is coming from and set the standard in the right place thus making passive a household name.

Brilliant Terry - a very real energy view of a real house using the novel Willis approach. Also a great example of what good instrumentation can tell you.

It will be interesting to see the overall figures and how the £150 compares to the full total.

Looks like a material change so planning will need to be informed and grant the change, as you are using an architect, very sensible in my view, you will need to pay additional fee for the use of an agent for planning IIRC, assuming they processed the original application.

Very tidy tilling - only one oven - are the others hidden away out sight? Still in these days of lock down who has dinner parties anyway!

We looked at this system, I think they use standard heat pumps, just checked and it is Samsung, and they offer systems with their own cylinders and Samsung heatpump, so the heat pump will be good bit of kit but not sure of the cylinder - hopefully more experience out there in the hub.

Looks like a great challenge - welcome

Sadly this is now a standard political pattern wheeze and is used all over the economy. The help to buy scheme for new homes is another example and we will no doubt see many more flogging along with the green agenda. Don't get me started - back to the build ......

Hi and Welcome to THE forum for self builders - there are few of us in Kent so you are not alone, we are Building in Whitstable, frame now up and coverings going on.

Thanks Guys really helpful @PeterStarck I could go from the inside but would be difficult on the roof and @MarkyP you are right we will be battening over so just fixing down will be the way to got and using washers. Looks like the MARMOX washers and 50mm spax stainless screws @LA3222 will do the trick so will have a play with some of them and see how I go. On the 80mm thick I will need longer screws but same basic approach all good - many thanks.