scottishjohn

looked ideal for refurb of old building to bung up all the air leaks ,looked at this type before for exsisiting house,but not something you can DIY when iasked for costings its costs about same as pur foam but gets into all the nooks and crannies that most builders will not take the time to do or realistically cannot get to on an exsisting building. so yes for an old building and refurb ideal solution Ive seen stables use it on the old roofs from underneath to stick all the slates together --great for that also stops the corrosion of the beams by hot horse Pee fumes

If I had built roof same as you have done I would probably come to same choice , as fitting insulation between trusses is a pain and you have alot of space to fill.

manhole in utility is a bad idea last ditch --you would need special manhole--sealed type and do really want the chance of problems inside house.

I certainly wouldn,t be using inside of sip as ceiling I would still batton out for service void+air gap and then use foam backed drywall . do your upstairs rooms have slanted walls or a flat ceiling?

they will be airtight if you put them together correctly with some low expansion foam on joints . rot is again an installer induced problem --like laying roofing layer directly onto sips with no breather gap or just single battoning under slates to give a nice dam area for water to sit. I couldn,t believe the first typical scottish "sarking board" roofs with slates nailed directly to them that I saw --but then it was obvious they had gaps between boards and same temp either side of the sarking --no insulation in those days plenty of space for water to get out and of course wood 200years ago was a different thing . yes there is a limitation to span,as with all things without some gable to gable support beams at ridge and one half way maybe I,m no structural engineer so length i cannot say , but it will still be far less intrusive and more usable space up there than other systems if you have any ridge height restrictions. and of course the main roof structure is on in a day

I take my experience on a sips roof from comparison of filling my flat garage roof with similar kingspan insulation before it was done it was very hot in summer and very cold in winter ,as in cold enough to freeze the water tap in there,now it does not freeze and in summer it no longer a hot box, blown anything will not compete with PIR unless as you have found are 3 to 4 times as thick . double battening of roof gives you at least a 76mm air gap -100 if using 50mm battons and nothing insulates better than an airflow and keeps everything dry I have an industrial seafood cold store on same estate as my motor biz and its made from pir --only 6" thick --and i even went out with my thermal temp gun and checked it -- ambient on outside -40c inside. I checked the edge of the slab foundation and that is always -20c from ambient --cheap skates did not insulate the edges or underneath it I suspect i watched them build it-- so i will not be convinced anything is better than pir for anything like same thickness,gives you more headroom for same ridge height + definately no air leakage + why use I beams when the sips take the load If you build rooms with no windows and they won,t overheat which is impractical unless its a storage space -usual velux,s will get maximum heat from sun as they point directly at it, so yes without blinds and good windows they will soak up the free heat from the sun --maybe the place to specify different glass in the windows,not usual low iron glass, and so stop alot of the passive solar heating. you seem to worry about overheating in summer --not a problem i have ever found in scotland in the country side same goes for air quality --its that clean that leave anything in the garden and its green in a couple of months ,soffits need power washing every year for same reason except on south facing the cabin filters in cars need changing once a year in most parts of england --here they last 2 to 3 years before they start looking sooty --same for engine air filters at least twice or three the mileage before they need changing ,if you are not in glasgow or edinburgh, they are as bad as most of england

I doing relativley low heat plumbing --not a real boiler then have a look at unponor q+e system --no soldering using pex pipe--pretty idiot proof

then why not durisol if you want to fasten stones slips or get a "real plaster" to use cement screed on the wall to inside to make it look like concrete house--will be cheaper bare concrete not my choice will look like one of those grand designs .with galv conduit electrics ? what ever floats your boat

my choice will be sips for roof+battened drywall for ceilings ,as planning say 1.5 stories only and counter battened on outside then slates very easy way to get a good insulated roof space to live in

ideal for those rendering nice shape to work to well i have the luxury ,if that the right word as there will be 2 houses mine and one for brother --so maybe one will be ICF and one could be SIPS our real problem for ICF is distance a pump truck has to come 100 miles anyway

LOL well thats that idea trashed--but it will slow down heat leakage and should help to stop stagnation by keeping temp down until the concrete heats up , ok then less concrete more water storage--but still think it will be a non starter due to cost of tank with all complications of expansion of concrete etc - I do have 5000litre grp 10bar pressure vessel I converted years ago +insulated etc --but wife would not let me bury it in the garage a work of art making the copper solar coils 22mm input split into 12 X10mm pipes wound up looking like a hill billy still and out put coil was 1" single copper coil at top of tank tank is 8ft long x 5ft diameter all cradled in astrengthened plywood box--weighe 5tons when full and 130mm phonelic foam around it then air gap and double bubble foil then air gap and plywood outer casing my workers were quite worried when i pressurised it to 4 bar to test it all . all good fun --myabe i,ll weigh in the copper and make it into a simple garden water storage tank at new house--or maybe just try it first for a season in the new garden -and so what temp i can get it too--loads of space to play about If i still have the energy after building new house!!!

you will get big heat losses from the evaporation of the water if not a sealed and slighty pressurised.. you would have probably been just as good to use the old roman method --duct chimney around house wrapped in fire bricks and use all the heat from the logs and the flue gases. LOL

my idea of the insulation on outside of tank is to use the concrete as a large heat store which should stop the panels from stagnating --concrete will hold 5 times as much heat as water ,but heats up and cools down slowly. and get to 90c by end of summer and when tank drops below min set temp divert solarinput to smaller buffer tank or direct to floor +switch back when it makes more than is needed for immediate use. I had a calculation done 20 years ago by thermomax when i fitted first tubes --with my house it worked out I needed 20000litres storage +6x20tube panels to get 80c by end of summer for full years supply with a small possibility of needing to use electric inline boiler as back up -heat loss they claculated at 1.7c per week using 140mm of phonelic foam on outside. anymore and the difference is really academic -just cost outweigh the extra thermal gain now we are talking about a totally different house so numbers must be just a small fraction of that.as that same house uses £800 in electric for the ASHP -- my feelings are it still won,t be practical . 26mx2.6mx2,6m water storage tank +another 140mm of insulation all round the concrete +--but I,ll wait till heat calcs are done for final decision

lets face it a sensible scheme done by folk who have half a brain +not falling into the obvious traps wouldn,t make good TV - so no chance of being of any interest to to kevin now the cob castle was a good case in point . I like the idea but surely some sort of temporary porous formers on outside and the use the digger to compact it would have a more sensible idea

I have done lots of study on the various makes of ICF ,and would suggest you also look at integraspec ,they have some nice extras nudura and others don,t .. like chamfered window closing pieces which means you have no wood to possibly rot away and total foam surround to wall so definately minimum cold bridging. my attraction to durisol ,if i do go ICF, is the thermal mass inside the insulation . parge coat is no big deal cos not like plaster finish is of no importance --just fill up the surface to seal the "weetabix" finish choice ? as far as i can see they can all take any sort of finish you desire .

as the title say tell me openly and frankly why you prefer one type over another or why you would not build same way again still trying make my mind up which way to go

the advent of cheaper pv storage could make a big change ,but costs at this time --a bit iffy

bit hard to get real comparison as no heat output given or even staed on navitron site for evac tubes and as istated earlier the key is having enough storage so panel never gets to stagnation point in a day . will look again later when fulldesign specs are available for house all information is good and added to the pot for cogitation prices for solar thermal are now much lower and a 3sqm panel can be be under £500 --your solar pv is 250-350 for 325watts solar thermal when enough sun from that one panel will be 1800w,quoted kingspan thermomax 30 tube panel spec, so all depends on how much free power with pv you need to use i suppose and how much hot water you need never simple

thanks will give this a look

I understand why you do what you do --"seems a long way for a short cut" and complicated when one solar thermal will do so much more 80%of the year minimum to a much larger volume of a tank and a very simple control system maybeyou would get more where you are --but it does 80%+ in scotland no problem and htat was when we has 2 girls at home --now just the 2 of us even easier

and air test should be done before dry wall is fitted--and not just seal up the skirting boards. Iwill certainly be doing my air tests at that stage

your point on not using certifed ainstaller is noted anf filed away . do you use ashp for hot water as well as PV.

I had this heat leakge problem with the tank when first supplied,as the foam used was rubbish i got PIR steam pipe lagging pipe sections and put them round tank --problem went away .no dhw tank is supplied with enough or correct insulation they are made to a price ,so they use low grade foam that is pumped into jacket ,even old style copper tanks which do have proper type of phonelic or PIR insulation on them ,are not good they need extra and include all the pipes coming out from tank ,if you want to keep heat in right place . physics tells us that making electric to then use it to heat water has to be less efficent than diret use of sun ,you are just trying to make use of PV electric that way and if no FIT --that don,t make sense-- anyway time will tell with what happens after FIT is stopped if it is not replaced by something else I can,t see how fitting pv in new roof will save on slates as you have to have something there instead if its cost then you do not use slates at £9-15 per slate for welsh slate at 19slates sqm that is lots of money £170-£285sqm use concrete tiles at around £1 each which equates to £10sqm or recycled concrete /slate mix at £20 sqm yesI,m a scot --every penny is a prisoner how much is a recessed pv roofing panels per sqm

unless they change things after the RHI grant stops for PV i doubt it will be viable any more --time will tell. ASHP has everything beat at this time I have a mitsubishi plumbed cylinder unit on my heat pump on current house -which is why i dumped solar ,as the anti legonella function knocks tempup to 60c every now and then which makes best use of solar in moderate months not that good .i have alot of experience over the years with solar thermal and it all revolves round getting as much out of it when its day light ,so lifting tank temp up by other forms stops solar working for a lot of hours . good control of what does what is needed to get best form it--simple dhw only --you just want a big tank i used blender on dhw supply so i only took minimal hot water from tank at 45c after cold blend --no point in putting lots of cold in it at the tap my tank ahd dhw coil at top UF in middle and solar coil at bottom and boiler heated parent volume when solar could not or UFH demand was too high for solar cop when raisng dhw to 60c is not good -- what i can say is when i swopped from modern lpg boiler to ashp i saved £1300 a year --house is not up to modern insulation stds add that to RHI and ashp is no brainer even on an older house if no mains gas --if you have rads then they need to be changed for ones designed for heat pumps

you have basically confirmed my thoughts --fit ufh in good insulated slab anyway , our climate here is very similar to cornwall --continuos spring interspersed with a bit of cold and heat # over heating --wife will soon sort that that -she is a window opening freak . so sounds like smallest ashp you can get --3kw will kill the job . Or i might go for solar thermal as ihave had until recentely 2x20 thewrmoax evac tubes onroof of present house 20years ago idi a retro fit underfloor system in this house by routing all chip board floors ,then coveringwith 6mm ply it has workeed well and solar actually contribute to space heating as well as the hot water# downside was storage tnak not large enough at 300litres so in summer it sometimes looked like a steam engine . kit i got then was crap --not the tubes ,but all other bits ,like plastic air separator unit --yes it melted and so did the panel sensor rersult so much heat that the plastic insulation melted off the copper pipes --so thats 170c + for sure . maybe will do what I always wanted and use to .solar thermal and large tank if heating load is as low as you say . the day I finished the installation was in february --i turned off lpg boiler and on a good sunny day it would run UFH att 25c + lifting tank to 50c so maybe my nutty professor idea of a 5000 or10000litre concrete tank insulated to death on outside could be a winner will wait to see final heat clacs when house is fully designed to make decisons --evactube panels are half price of what they were so i could have twice the are for same price