A_L

I knew you did, I was just being provocative! I used about 20.16kWh of gas for CH/DHW that day and averaged about that for the week.

Saturday 02/05 I used 4.4kWh. It was washing day. ?

Yes, but the move to 140mm was originally to accommodate more insulation in response to building regulations changes. If you have a lightweight roof then I would have no worries structurally. A brick/block outer skin has no/little effect on the U-value achieved. To get 0.13 U-value I would expect at least 300mm of fibrous insulation or 200mm of PIR/PUR

Its wasps, in our climate wasp nests are not multigenerational. They die out each autumn, there have been a small number of cases where nests were kept warm by displaced insulation and these were multigenerational but they a trivial in number. At this time of year a wasp nest is golf-ball sized with only an adult queen and larvae at most. Last years nest is full of disease because of disorganisation in the colony in autumn and new queens instinctively avoid them. Builders might adopt an 'ain't my problem' attitude as they will not understand/know its empty. You can just cut it down with a saw, it only paper mache, or if your nervous about it leave it to January when it will very definitely be safe. Adult wasps get at least some of their energy requirements from an excretion produced by their larvae, when the larvae die out in late summer/autumn the adults intensify their efforts to obtain sugars from fruit trees etc https://www.nhm.ac.uk/discover/what-do-wasps-do.html

here is a another cement bonded particle board building-board-product-and-application-selection-guide_2036226.pdf

@bear 1, Hello and welcome. Please describe the locations and appearance of the condensation and the structural details of the perimeter elements (walls etc), particularly levels of insulation.

I would use airtight breather membrane rather than dpm, less risk of interstitial condensation. Support it from underneath to produce a small cavity. You could then fill with loft roll insulation. You could add polythene across the top of the insulation.

You probably need hot water every day, the amount of heat requiring removal from the cold room would be quite small and could be part of the supply to the DHW cylinder. A dedicated heat pump would still be better. Only relatively, both are colder than the earth of the ground loop location. Yes I am thinking the extra warmth represents an increased heatloss wrt the house but if the return is also warmer it may balance out ........???

@Thorfunmaybe they just have a more risk averse structural engineer or software design package

1.Waste cooling? The ground loop fluid leaving the heat pump would be cold enough to act as a source of cold to absorb the heat in the cold room by routing through a heat exchanger (radiator) in the cold room. 2. You would have to have two routes for the ground loop fluid to go back to the ground loop area. One via the cold room and one not. Which path is taken would be controlled by a thermostat. 3. Doubt it very much 4. I wouldn't, for reason see 5 5. You would effectively be increasing house heating load by pumping heat from house to ground lump area. This is because by heating the ground loop fluid in the cold room you are reducing the amount extracted from the ground loop area Better to have a dedicated heat pump with its 'hot' output in the house.

partly, studs carry loads from the roof and you may need more to take this, also the width of a stud could be less at 400mm centres e.g. 89/100mm instead of 140mm

Unpruned autumn fruiting raspberries can fruit twice per year but the total yield is less than if restricted to the autumn. The unpruned autumn cane will have fruited at the top last year, the lower part will flower and fruit at the same time as summer rasps this year and the new growth will flower and fruit in the autumn as usual. So if the tops show no sign of flowering (in June or so) you have autumn fruiting rasps. You then have to decide if you are going to double crop for one year, you should cut the tops off leaving the bottoms to fruit, the embryo flowers should be visible, or cut them out completely and go for a (reduced) autumn crop. In either case I would feed heavily. Summer fruiting rasps will flower obviously at the tops of the canes. I would aim for six canes per foot run of row in either eventuality.

Yes, Jean Pain methods https://waldenlabs.com/compost-water-heaters-from-jean-pain/

Mix both well with grass clippings. The paper is high in carbon and will help balance the high nitrogen of grass clippings and help prevent the grass from clumping into a wet slimy mass.. If you have large quantities of broadleaf leaves they can be composted on their own to make leafmould over a 2yr period with frequent turning. The most important thing is to cover to retain heat but also to keep the rain off.

Yes to both points. If you change the mineral wool batt layer to 85% does the calculator not offer room to enter 15% timber or put in such a custom layer? No, 4.8.6 on page 11 of the document from me that you downloaded recently

1. The correction is a default value which may/may not be appropriate. 2. Probably indicates a dewpoint, however my software does not indicate any dew point within the wall as given, even with the polythene removed there is no dew point. It may indicate where the temperature is low enough to start to condense but this does not allow for the vapour pressure reducing effects of the materials in the wall. 3. No airspace required The unventilated airspace thermal resistance would be correct if the plasterboard had a foil surface. The calculator appears to have the ability to accept custom values More important is no allowance for the timber fraction in the timber frame and less importantly in the service cavity. I estimate with a 15% timber fraction (default value) the build up has a U-value of 0.179, without allowing for this the U-value is 0.155 The external resistance R-value is already allowed for in the ventilated cavity R-value, although there probably is no way to prevent it being added by the calculator. The timber cladding R-value should not be included as our recent conversation (outside a ventilated cavity)

@Thorfun Correct.

Correct @Thorfun, there is however a small additional thermal resistance that can be added to 'rainscreen cavities' such as yours. The cladding lowers the average windspeed in the cavity compared to the outside air. This allows what is called the 'external surface resistance' which is normally 0.04m2K/W to be increased to 0.13m2K/W. The external surface is the breather membrane on the inside of the ventilated cavity. See pages 11 & 12 of the attached pdf. BR_443_(2006_Edition).pdf

Silvered membranes can increase the thermal resistance of unventilated cavities next to them. By default around 0.25m2K/W or higher if tested as those already mentioned (over an ordinary cavity of 0.18m2K/W) It is important the cavity is unventilated as it has no effect on ventilated cavities. Unventilated is deemed to be no more than 500mm2 of openings per metre length of wall.

Assuming you mean a vapour open membrane to go on the cold side of the insulation:- https://novia.co.uk/breather-membranes/novia-black-pro-146gsm-roof-and-wall-breather

What is the distance from the top of the original floor to the top of the new floor surface and how flat is the original floor?

At 70mm the maximum thermal conductivity needed is about 0.024W/m.K so no realistic alternative. EPS300, thermal conductivity 0.033W/m.K would have to be at least 100mm to get 0.28W/m2.K The 150mm slab will spread any wall load to a considerable degree, wether sufficiently will depend on exact construction details

Obvious typo, can you give actual exposed perimeter and floor area. What is your target U-value (building regs for England?).

Is this being done under ECO? Large CO2 savings compared to deemed electric heating could fully fund the installation. The system should be installed according to MCS specifications and should be capable of normal demand temperatures. The system may have to be operated for 14-16hrs per day to achieve this. If the cottage is large you may need a 3-phase heat pump, generally if output of heat pump is 14kW or more. The radiators will be sized to compensate for the lower flow temperatures

Probably the difference between expected outside and actual inside temperatures.