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Defo not HWRC for us, purposely designed NOT to need it, tbh couldnt see the point of making thehouse super efficient and then running HW around the pipe syetem just so you can have instant HW. If you are super insulated and more importantly, airtight, then a log burner will almost certainly over heat your house in next to no time. We chose not to have one mainly due to pollution issues, but also because the times we could actually light it and remain comfortable would be extremely limited, even here in the Lake District.

I made a spreadsheet up once to work out from the absorption/transmission and reflectivity due to angles how much energy comes though a given area of glass. Did it for our @Jeremy Harris, so was a few years back. I may have it on a backup somewhere (I am overdue a new main backup), shall have a look if I remember. One of the problems with solar gain is that it is soon forgotten in the UK. 3 sunny days and a thunderstorm and summer is over. Though last year we had, down here in Cornwall, an extreme heat wave warning (the calculation is nuanced for a heat wave). I covered my SW facing windows (half my wall area) in tin foil. Worked brilliantly, room dropped 10°C.

You could try self amalgam repair tape.

What is anyone doing chipping something 3" diameter? That is good firewood. What a waste.

From the spec "Ultraviolet Transmittance of UV 11 %" Peak Solar irradiance is around 1kW/m2 You say your roof windows are 134cm X 98cm (1.3m2) and 134cm x 160cm (2.1m2) or around 3.4m2 in total. At 11% transmission this would equate to a heat source of no more than 380 Watts. Of course it will depend on the area facing the Sun at any given time. It doesn't sound like much but I have roughly half that area in my worst hot spot and it does push the temperature up by a few degrees. This is when all your insulation starts working against you!

Right, had a look at this WU station: https://www.wunderground.com/dashboard/pws/ILONDO480/table/2022-06-17/2022-06-17/daily Seems temperatures peaked at 33.7°C and had an average of 25.7°C, minimum was 16.7°C. You also had an hour, 12:09 to 13:04, when the solar radiation was over 900 W/m2. That is really quite impressive. So I think most houses would struggle with that.

What exactly is your wall make up? Our calculated decrement delay time was 13 hours and it certainly seems to be close to that, our house maintains a pretty constant temperature only warming up or cooling down slowly. You need to eliminate solar gain as the culprit so even if you can make temporary exterior blinds to prove a point e.g even something as simple (on a dry day) as cut a large piece of cardboard and tape that to the outside of the velux windows for a day to block the sun out completely.

Tried ebay? Single motor version £55, double motor £75 - still expensive.

Have you looked under labels and rubber feet for hidden screws?

I put 150mm celotex under the main concrete slab (extension) and 200mm foam glass under the limecrete slabs (old cottage). so heat loss downwards shouldn't be too bad.

Yes, but in principle fix it to whatever is available, the columns and any roof ties. With the height especially the wall is becoming very slender, but then the cavity wall consruction helps a lot, and especially if you use sturdy cavity ties rather than the wire ones. Your situation is unlikely to be in any examples, and the flat blocks are likely to be stable in themselves. Any cross-walls will add a lot of stability too.

Hi chaps, apologies for absence- currently ill, got 3 oldies needs to deal with, & a deluge of (paid) work. Will hop back on board midweek. Then to get the ball rolling. Fab help so far, zooter.

Well it either will be done before or done on the day, there is nothing like a critical deadline for getting things sorted.

That's it, constructive criticism at it's best. Your technical insights are always welcome...

600 are fine

Well, after what seems like an age for a decision (6 months), we have finally been granted planning permission. Not sure when I'll start but need to start thinking of the construction method and external finishes - currently leaning towards ICF construction as it lends itself well to the basement construction.

My friends have this in a large house and are very happy with it. I almost went with it but we have a giant bath so to be safe I went with a system boiler and UVC. Happy with my choice of Veissman Vitodens 200-W 35kw system boiler. I went with one wiring centre and manifold per floor and then put a Tado thermostat in each zone. I have 12 zones, one in each room. Expensive, but I’m happy with it.

When I did my solar PV at the old house, I notched the tiles that would otherwise have rested on and be lifted up by the bracket. Easy to do with an angle grinder.

WC vs load compensation. You can have both. Master thermostat, just decreases flow temperature, but it applies to all rooms not just the room the master thermostat is in.

You need to measure it out so you don't end up with a half brick in the wall when you get to the end of the run. When you lay them out dry then you will get to a point where a full brick won't fit so depending on how much you need to get one to fit you either open the perps up or tighten them in to suit your needs. Also helps with setting out where doors and windows go so you know the perps are all plumb and not moving to one side to fit a window in as it's really noticeable when you know what your looking at.

For fridges the estimated power consumption is part of the published technical information. And as they run 24x7 it should be a reliable estimate. I don't think you will find an A-rated fridge (wine cooles only afaics). The scales have been redefined to (I think) get rid of A++++ and similar? An old A is a new D. But scooting over to Appliances Direct, and looking at a D rated 390l fridge and E rated 230l vertical freezer, I get energy usages of 78 kWh and 154kWh per annum. That fridge is an improvement over my 6-7 year oldie, and the freezer is a small improvement. (Both Appliacecs Direct and Currys have energy rating in their range of filters.) These are the not altogether cheap models (£1100- and £1000- 🙂 ) - Liebherr. https://www.appliancesdirect.co.uk/p/kef4330/liebherr-kef4330-freestanding-fridge https://www.appliancesdirect.co.uk/p/gn3735/liebherr-gn3735-comfort-freestanding-freezer On your 32kWh per week = 1650 kWh per annum, your extra usage is 1400 kWh per annum, which at 30p per unit is £465 potenital saving per annum. That will cover in short order your extra costs for a top end fridge and freezer over slumming it with a Bosch or Samsung, even if optimistic) ! But I note that Appliances Direct have a number of refurbed big Liebherr fridges at £750 here (30% off): https://www.appliancesdirect.co.uk/p/a2%2fkef4330/liebherr-a2kef4330--freestanding-fridge So I'd recommend a look at that, or the full price version. I got a Liebharr ex-showroom model Fridge-Freezer combo, and I would now happily pay the full price if it ever needs replacing. Worth their weight in bubbles. I'd say it might be time for a new fridge and freezer. Ferdinand

You need to cut out any sunlight directly penetrating to reduce gains. On Velux, external blinds work best. For cooling a split A/C is best. In my house we only have internal blinds and A/C is not practical to install. Some of the bedrooms get hot in the mornings. Luckily my office is on the ground floor so is tolerable.

If you're ever passing Cambridge you're welcome to borrow my pressure tester. 10 bar will find any fittings that you forgot to nip up. You'd be surprised what will hold at 1 bar then potentially pop off later! I bought it for testing / prestressing some underground district heating mains - take to something like 20 bar, wait for it to stretch, then take back to 20 bar and hold overnight / verify that the drop is as specified. Only then do you trim to length and make the final connections. (it stretches it bucketload and it you don't do this then when it's warm and at normal operating temperature you'll find it creeping into the houses...)

The vertical load comes down the studs. Yes, the OSB shed's load but ignore that conservatively. The studs are checked not least for the following load cases: 1/Full roof and wall loads plus anything else acting as a downwards load. 2/ Other case which include wind and snow. The main thing here is nearly always load case one. The compressive strength of timber is much more when axaily loaded parallel to the grain. The critical compressive (bearing) check is at the base of the stud. Here you have the stud loaded parallel to the grain bearing on a horizontal wall plate, the grain of the wall / sole plate here is loaded perpendicular to the grain and this has a much lower compressive strength. Conservatively assume that the load goes straight down and does not disperse through the sole plate at 45 deg. Thus if you use a timber packer under the sole plate of the same width as the stud and same length as the width of the sole plate with an equal or greater compressive strength perpendicular to the grain.. that will satisfy the bearing check. If in any doubt get some 50mm (same width as the stud) wide oak / hard wood and rip that down to make a selection of packers the width of the sole plate. Soak them in preservative after cutting for good measure. Have copied part of a table from the BS below. You can see here how the compressive strength of a timber is much more when loaded parallel to the grain as opposed to perpendicular. You can see for a C16 the compressive strength of the timber loaded axially is 6.8 N/mm^2 and the the sole plate (loaded perpendicular) is 1.7 N/mm^2. Fill in any gaps with something else, maybe add the odd extra packer if you have any doubts about the above and get some extra load spread due to the load sharing properties of the OSB / sole plate / bottom rail of the panel. You may want to do this to spread the load more evenly over the underbuilding if you feel this may be an issue. For all .. do not use plastic window packers under your timber frame as the are not solid.. they are for windows.. not structural loads. You can buy the right plastic packers for timber frames on line etc.

Haha thanks Mike, I have definitely done the chocolate laptop trick before. We have just booked the NSBCR in Swindon I think - will have to check with my wife who is sensibly asleep. The airtightness course is a great idea and not something I had considered, thanks for the advise!

French doors. Ours are 1m each and open in. Not as sexy as sliders or bifolds but a fraction of the price.

If you want to do several rooms that aren't well interconnected, then you need a multi-split. Essentially the same indoor units, but the outdoor unit has provision to attach several sets of pipework. In principle it's little different to installing a single mini-split, just a bit more pipework to run and connect up.

Stops "them" listening in too 👍

According to Google the sun will expire in around 8 billion years . Just wondering if you’ll get this done in time ?

@MortarThePoint mate, you need a bit more tonic in your gin. 🤣🤣

Welcome back. You see the self build bug is adictive. They say you probably get it nearly right by No 3.