saveasteading

When done, and the demo wood has been used, we will have any amount of abandoned branches in the nearby felled commercial forests, but it is probably too tarry for the only wood in the burner. There is a little area of woodland but it isn't far off being natural so don't want to touch that, including the fallen trees that are full of oozy life. Any advice on pollarding? If we were to plant soon, what trees should we use? Sand underneath for 1-2 m then probably rock.

It seems to keep the sheep cosier than a layer of fibreglass would. But I see what you did there: R = Ram U = Ewe λ = lamb I have found some stuff on converting wool, and it would seem to need an awful lot of washing, to get rid of manure, lanolin, weeds etc.so perhaps not as 'green' as it might seem. Maybe try washing a fleece in the cement mixer next summer.

Civil Engineer with capitals please, as many a groundworker has decided to hijack the term.

I am familiar with the substantial air gap at the interface of a bottom cleat for metal cladding (disregarding the old detail of not facing it at all. Our detail had a flexible mastic under it, but there were still noticeable gaps. Best found by looking out from dark to light. Tape was the answer if it was too wide for mastic. ( a long timber or steel onto concrete will have gaps even if in tolerance), and you hope it stays there permanently. We will be doing this properly! No air test required so all the more reason to look for the gaps as we go along.

I mean the output pages. There are lots of histograms and pie charts telling you where you are using notional electricity, including cooling and heat exchangers. I can't remember if there is even any allowance for where you are in the country. Your assessor should be able to copy it all to you. It is genuinely interesting, though annoying.

I need convincing on that! anything I have looked at would never pay back the capital. Even running the cold intake past the waste involves a lot of rerouting. es sticky tape and mastic. Comes cheap by the box. With a new 'stick' construction ( now 1/5th of the job) there are lots of potential gaps, at the base especially. Do people place the bottom string onto mastic before fixing to the footings?

I have been involved with SAP/EPC (as a targeted building designer) since the very first talks by BRE. Along with most others present I left at half time when they couldn't explain where any numbers came from. I think it was rushed through before it was ready, like Breeam and air tests, because it was a money-maker. Lots of approximate assumptions were included. Then once the programmes were written there was little desire to change them. The professional assessors can't change the formulae in the core programme, so you chuck in some numbers and tick boxes and out comes a rating. We bought the core programme and played with it to see where the anomalies were, which was fun but annoying. There were lots of tick box items which didn't make any sense to us, and I think the experts learnt which give the best outcome. For your own interest you can insist on the dozen or so back pages of the assessment. There you will see the assumed power consumption when your ashp goes into cooling mode for three months for the Highland summer, and the power used by heat recovery. Then deduct that manually for an academic A++

Shiny layer is ok straight off the cooking foil roll but fades over time? Is it the shinyness or the aluminiumness? It appears to me that a silvery barrier will add about £300 to the project cost. It all adds up but that seems ok. Up for suggestions of where better to invest the money. I'm more likely to be a bit overdone and tough.

I agree not a big problem but it is ugly and could start to spall the bricks esp in frost.

and yet BRE say use 0.18 for a 22mm air gap in a wall and 0.44m if it has a shiny layer. Instinctively I think this feels about right, because aluminium absolutely does reflect a lot. Build quality et al are much further down the line and are not in the warrant application. For now I want to put in a reasonably accurate heat loss proposal, that is fairly mainstream and uncontroversial. But I really don't want to change it later, so am deciding on fundamentals like PIR or mineral wool. shiny membrane or not. It isn't easy as the standards for a change of use are rather high, not that we wish to cut corners anyway, and there are lots of constraints due to the existing geometry and structure. I'll see if I can summarise the points you mention. The surface area is huge. back to shiny: we are fitting out a roof area as site office, with PIR between the rafters and lined with a shiny membrane. With Infrared heating I think we will get quite a lot of that bouncing back in, and it will be a bit like being the turkey in the foil. Will report on this when done.

No thanks. has calculus in it. Care to summarise?

Good point. Plus wind blowing it back to the wall.

At the right hand side you have a gravel bed at the bottom which will take the water lower, then it drains away. Less water will reach it anyway as there is a lot of brick to absorb the rain. Under the door it is paving slabs and no gravel, and all the rain hitting the glass runs straight down. Check that the paving runs properly away from the house, all the way from the wall. Golf ball test. Check if rain running off the door sill is dripping onto the ground or running backwards and down the wall. it is all below the dpc and you seem to have ventilation, so prob not along term worry, but better if it didn't look like that. Guessing that this wall faces the prevailing wind so south-westish.

If it doesn't show any signs of decay then all is well....for the moment. Better left out in the air so it can dry intermittently than encased in any screen, so the best thing you can do is progress.

No. the concentrated load needs to be spread efficiently. An ordinary block is likely to crack and then concentrate the load directly below. Why would you want to not have a padstone? Tell us please. If the geometry has gone wrong then you can make it on site perfectly well, but ask the Engineer to give you new dimensions. needs high quality concrete, I would put some reinforcement in it because, why not? You can also buy all sizes of padstone bricks and blocks, and build to suit. Basically it is made from structural concrete without the usual fillers that keep costs down. Assuming someone has designed this for you, ask them for a revised detail if you have to.

Today I will mostly be doing the same again, trying frametherm in the U value calcs, adding in the effect of heat loss through the rafters and studs, and finding a way to get better numbers. 1. pass all the tests to prove it to the BCO 2. actually get what is best for the building and bills in the long term. Perhaps these are in reverse order. Question. Please excuse the avoidance of jargon and scientific precision, and I am thinking here only of keeping heat inside. We 'know' that a shiny layer helps insulation, by reflecting the radiation, but only when it faces an air gap. Theoretical U value for the gap jumps from .18 to .44 if I remember correctly. BUT does that not depend on the aspect? Heat (radiation) from inside travels through plasterboard, hits metallic layer on inside face and it is reabsorbed back into the plasterboard and the membrane itself No help and no hindrance OR hits the shiny stuff on the other side of the gap and bounces back into the gap. Warms the air and helps the insulation level. Then the reverse occurs at the outside...let's say PIR is left 50 short of the sarking. to provide a ventilated space. Then the reflection is again inwards, to no advantage. and anyway the air gap is ventilated so the effect of the gap is low or nil.. Which could bring us onto multifoil, which is not in our recipe, so I won't go there. Red pens out as necessary.

Yes primitive isn't it? Sarking is standard in Scotland. 150 or 225mm boards still available in quantity at merchants, £20/m2, pressure treated.. But mostly used for maintenance. Osb is normally cheaper, and is certainly quicker. Contrary to the understanding of some, not all Scotland has any more severe weather than the rest of the UK, but it is simply a sensible thing to do for UK weather generally. I don't think our steading would still be standing after 120 years if it didn't have it. Did the people who wrote the BS consider the differences? Nuff said. The slates are impermeable until they break, but at least have double cover unlike modern tiles. The gaps are very permeable.

Do you have a dpm under the concrete? If so the PIR boards will trap the water in the concrete for ever. That would be a bad thing. I will have to think why, but it just is.

2 layers of metal cladding. firstly lay metal cladding as if it was the weather layer, supported on rails. Then there is a steel spacer system to provide a raised support. lay fibreglass to completely fill the space another layer of steel cladding, screwd through a thermal break layer. all ends must be completely closed off to keep birds etc out. the height of the spacer system dictates the amount of insulation you put in. anywhere between 100mm and 400( if you are in Iceland.) The advantage is the low bulk for delivery, and steel/insulation direct from specialists. Also it is all manageable by hand whereas composite panels are very heavy. This works but whether I advise you to try or not depends on your ambition and skill-set.

Yes that is correct. The wind whips through the slate to the sarking. Currently it then whips through the 2mm gaps and the whole building, and that is where the detailing comes in. We are now proposing a partial rebuild of about 20% and will use metal to differentiate old and new, but to the same geometry. Metal cladding I know nearly all about. Would normally seal every single joint of panels and flashings with very special mastic tape and fillers, but the whole industry doesn't necessarily do the same. For the steading we will do what others do, and set it on double battens with the air through it and any dribbles running down and away. NOT secret fix but screws proudly on show. Metal cladding that is permanently wet will rot in a short time, regardless of coating and galvanising, unless it is utterly undamaged, cut properly and has hole-sealing screws. The next worst thing is bird mess, just as it is for cars. Hence double thickness plastisol if near the coast..

For something that will work better and satisfy the rules Civil Engineer. For an attractive approach to the house: Architect. All with capitals.

Short answer. Could look good, certainly characterful, but will be a very cold surface.

ProDave, I came across this about an energy survey. which is perhaps relevant to your annoyance at your energy rating The SBEM prediction for post-improvement emissions (8,135 kgCO2) is extremely high in comparison with all other modelling programmes. The reason for this is almost certainly that SBEM assumes a greater use of electricity (mainly for the proposed heat recovery ventilation system) than the other programmes. This is covered in more detail in section 7.4, but the result is that it skews the post-improvement average (an 88% improvement at 2,589 kgCO2); removing SBEM from the equation would change this substantially, giving a 93% improvement to 1,480 kgCO2 and more on p23 here if still annoyed and interested https://www.changeworks.org.uk/sites/default/files/Historic_Scotland_Technical_Paper_8.pdf

yes but. There is quite a variation on it so a 25mm gap is handy for lots of reasons. Also some areas of loose render that will have to come off. Lime plaster....never again, having been ripped off once. I have been looking at fibre board today...maybe on some of the roof, although the eaves have zero over-sail so is a tricky detail. Is it an alternative to plasterboard on the ceiling? The 600 granite walls will have a U value of 1.8 according to the documentation IF dry and IF not severely ventilated. But the good news is that the ground is superbly free draining so rising damp should not be a problem, and I am proposing to close the voids off to allow local ventilation but no draughts. More curveballs please. The analogy fails though if I say I may come back to that one.

Correct and won't be doing that. Metal cladding will be ventilated . Also would not happen if every joint was sealed but that is usually not done in domestic. If presented as a holistic design then yes , or I should hope so, as the traditional sarking is 200 wide then 2mm gap, so lots of ventilation. Under osb with 2mm gap per 1200 then no, and that is what the 50 gap is for. But my question is about the logic of zero gap when the material is full-fill cavity batt. BCO's like proven details, fair enough, but things only change when questioned. There is a view on this forum that the gap is only there over PIR to boost the U value with a shiny face onto an air gap. As if they would do that to us. Also, sarking has always (?) been standard in Scotland and so there are far fewer accidental leaks. I couldn't believe that in a modern English house there was just the felt, and in an older one there were only tiles, and the snow could blow in. On our project the sarking is about 50 years old we think. It is rotten only where water pours in due to a complete hole in the roof. Where there are tiles they are sound, (and they were not treated)