Jeremy Harris

Mine is all in 15mm, with 15mm manifolds. Easy enough to get an all 15mm system and it makes converting to copper for any exposed runs easy (it's nice to have copper where any pipe is exposed, as plastic pipe always looks untidy, IMHO). No need for barrier pipe for water, either, barrier pipe (i.e.the stuff with a metallised layer to reduce oxygen migration) is only required for sealed systems where you need to keep oxygen out of the water. Oxygen is a good thing in supply water as it prevents the growth of anaerobic bacteria.

There may be other options around, but I've not found them. I looked around a fair bit and there were one or two that I thought might modulate power the way the Stiebel Eltron one does, but Stiebel were the only company that could confirm that they were OK with a warm water feed and would work as a variable boost heater (their technical chap was very helpful and the reason I bought their unit). What you describe does sound like a simple and easy solution. The reason I didn't go for the 12kW version was only down to the capacity of my CU, I couldn't find RCBOs that were rated at higher than 50A for it and you need a 60A one for the 12kW version. If I was starting from scratch I'd probably fit a separate small CU just for the water heater, to avoid having a 50A load through the main unit.

Not all the boreholes are for water supplies, many are for ground assessment. Any borehole over 15m deep is supposed to be registered with the BGS, but a fair few water borehole drillers aren't that diligent about registering their findings, whereas the civil engineering companies that do things like build roads, and drill holes to assess the ground underneath, are better at registering them.

There is most definitely a significant voltage drop along the length if you don't feed the high power stuff from both ends if using the full 5m length, as the track sizes down the strip are tiny, so if fed from one end the power tracks at the end the power is fed from are running at over their safe limit, so they get warm and they cause most of the voltage drop. Feeding the length from both ends halves the current in the feed tracks at the end.

They definitely run far better with power at both ends, plus the little 3A wire on the ends doesn't get warm! There is a fair voltage drop down a 5m length of the super bright stuff I found, hence the reason I fitted wires at both ends, to halve this.

One problem is that you can't adjust the compensation curve without the controller, and as supplied it will push the flow temperature up when it gets cold. The controller allows you to set the curve (or set points that make the "curve" a straight line, which is what I've done) and that definitely helps reduce the defrost frequency a great deal. I have a feeling that the cooling temps are also set to a less than great setting by default and the shut of temps are also not great, so it's well worth having the controller wired in just to gain a great deal more control over the way the unit operates, I think.

It's not likely that there will be a warranty problem, as none have an airtightness warranty that I know of, because they are so difficult to get to seal reliably.

You still need the controller though, don't you? I've not tried, but have the feeling that the unit throws an error if there's no controller found on the bus, probably because I think many of the settings are actually stored in the controller rather than the ASHP itself, so it needs it in order to run. The rest is just relatively cheap plumbing stuff. I found that adding an adjustable pressure bypass valve across the flow and return as far from the unit as possible (mine is just next to the UFH manifold) is very useful, as if you have any valves that take time to open it avoids the unit shutting down due to an over-pressure event and then waiting for several minutes before trying to re-start. All that happens if you do have a momentary period where there is a flow restriction due to valves being slow to operate is that the bypass opens and the ASHP modulates right down because there's very little heat being drawn off, but it keeps running, rather than shutting down, which means that the pump keeps going and as soon as the slow valve opens flow starts, the heat pump senses the change in flow/return temperature differential and ramps up the power.

Bifolds will leak air like a sieve and be a constant source of heat loss after they've been in a few months, so my vote would be to lose the bifolds (and save a fair bit of money and reduce the heating bills for the life of the building) and retain the French windows, with perhaps fixed glazing the other side. No one has yet invented a bifold mechanism that doesn't end up with air leaks, either from new or within a few months of being fitted, just because the geometry of them makes it near-impossible to get a decent seal. French windows are far better, as they can at least put a fairly even pressure on their seals when latched shut in cold weather.

Mine came with the installation manual (not that useful as it described connecting to an integrated Glowworm control system), the basic programmer/control unit (essential, as without it you can't set up or monitor the ASHP) and the unit itself. I had to buy pipe fittings, large bore flexible hoses (you need long ones, curved to reduce vibration transmission, as I discovered to my cost) and an in-line Y filter for the return connection (to prevent any debris in the system reaching the plate heat exchanger inside the unit). I also had to buy bolts to fix the thing down to the concrete base. Pipe sizing on mine was way OTT for the flow rate, 1" BSP male pipe stubs coming out the back of the unit IIRC. None need more than 22mm pipe (in fact mine would be fine on 15mm as the runs are short) so quite why they fit 1" fittings is beyond me, 3/4" BSP would have made things easier and removed the need for adapters, as I could have just fitted 3/4" BSP large bore flexis, with 90 deg ends, directly to the unit.

I, and others here, have older copies as pdf files. However, now we're running this forum ourselves (the members) we've opted to be a bit more diligent when it comes to copyright, so I'm reluctant to post it here as it would be a breach of the forum T's and C's. However, if you were to, for example, send me a PM then I might be able to help............................. SPONS is invaluable for a professional quantity surveyor, and the price well worth paying if it's going to be used a lot. For a single self-build then it is a bit expensive, especially as the chances are the build will extend longer than the validity of the SPONS data. It would be nice if SPONS produced a simpler, cut down, pricing guide for DIY'er and self-builders, as I'm sure it would be well-received, provided it was reasonably priced.

Interestingly this applies to all the Daihatsu-made "Briggs and Stratton" engines. It was a consequence of applying tight Japanese tolerances to what had been a pretty loose tolerance bit of American "engineering" (I use the term loosely, as prior to Daihatsu making the better B&S Vanguard engines they could hardly be described as being engineered at all..............).

What you will find, if your experience is similar to mine, is that the accuracy of that slab finish, together with the accuracy and squareness of the frame, will save a significant amount of time (and money) down the line. In my case it saved around 2 days labour on the flooring, could have saved around 30 sheets of (over-ordered) plasterboard, saved about 1 1/2 days in boarding out time and probably another day in first fix electrical fitting time. Had I known about all these small savings (that add up to a significant total saving) then I'd have been less concerned about the initial price. Like everything in building there are lots of hidden costs and benefits that you often don't find out about until it's too late.

I've stripped a well-used Honda GX31 engine (the one I'm planning on turning into a mini low voltage generator one day) and they are exceptionally well put together, really nicely engineered, so it doesn't surprise me that they are considered to be the "last forever" option.

Pretty much a dry sump, yes. They invented the system so they could get around the increasingly tight emissions regulations that prevent two stroke engines being used in may places and the first application was their range of 4 stroke strimmers and similar hand-held bits of kit. These have to work over a wide range of angles, so Honda came up with a cunning system that has an annular sump around the crank with a modification of the common splash lubrication system small engines use that turns the crank-mounted splasher into a pump. The centre of the crankshaft is hollow and the plate that rotates inside the annular sump pushes oil through the centre of it and thence to the bearings. It has a series of traps, plates and drains to both prevent oil collecting where it shouldn't and to encourage it to flow back to the sump. Here's a cutaway drawing of an early version of their design:

I can't see a problem with just providing a cat with a "safe haven" outside, personally. All it needs is the cat equivalent of a dog house, perhaps with a catflap on the entrance to keep it warmer, like the one in the shed posted earlier. What did cat owners do before cat flaps came along? I remember my grandmother always had cats (nasty Siamese things) and she'd put them out at night and let them back in the next morning. They'd always be sat on the mat outside the back door every morning, waiting patiently to be let back in. Leaving cats out, with an outside shelter if they need it, solves a lot of problems, in my view. When we spent a fortnight at a friends place in Portreath, "cat sitting" whilst they were on holiday, the one irritating thing I remember is that their cat (which was generally a nice enough creature) would come back in through the cat flap in the early hours and then scratch on the bedroom door to be let in and spend the rest of the night on the bed. I did wonder then whether a cat flap was really such a great invention, leaving aside the heat loss problem.

Depends on the make. Honda make a small 4 stroke that will run upside down or sideways (I have a bare engine I've hoarded to make a small generator for my boat with). Most usually give a maximum angle somewhere. The worst used to be the old Briggs and Stratton vertical shaft motors, that only needed to tip a little bit for the oil splasher to stop throwing oil around and so causing them to seize. The horizontal shaft engines, with their much deeper sump, never seem to be so fussy. If you can't find a maximum angle listed for your mower, then try finding an exploded diagram of the engine, as 9 times out of 10 you'll be able to tell from that what the oil level is going to do when it's tipped over a bit and whether or not there's a likelihood of oil starvation as a result.

You're right. I'm planning on calling in at CFS next time I'm down your way and picking up some G4 and loads of resin and gel coat. I have rolls of cloth and CSM already. The biggest job is going to be cleaning back the rough internal side of the stonework to get a half decent surface to prime and glass to.

There's some real history in those borehole records. At the far end of the village to where we're moving, there was a large WWI training camp (around 15,000 or so soldiers). It was all wooden huts and tents, so there is no sign of it at all today, except for all the regimental badges that the soldiers carved into the steep chalk escarpment behind the camp (see here: http://fovantbadges.com/ ). To supply water, the WO drilled several boreholes, some with a staggering capacity. One, at East Farm (this one: http://scans.bgs.ac.uk/sobi_scans/boreholes/398814/images/10728434.html ), has a borehole record that states that it was test pumped for "11 hours, limited by the capacity of the pump, but there is an ample supply, 96,000 gallons per day". The records in that link (in the following pages) show the layout of the old army camp, even down to where the hospital and firing range was located. Those who can recognise old army huts have spotted a few still remaining around the village, as after the war the locals appropriated a few as large garden sheds.

It really comes down to whether or not it's worth modelling things like corners. Geometric cold bridging has a very significant impact for houses with only moderate levels of insulation - our current house is a very good example, the upper North-West corner of our bedroom regularly gets mould, just because there are two external walls (with only ~50mm of bonded EPS bead CWI) and a loft with around 250mm of rockwool. The temperature in that corner is significantly colder than the rest of the walls, several degrees colder in very cold weather, and that's entirely due to the geometric cold bridge. However, if you increase the insulation level then that usually means increasing the thickness, and this increases the additional heat loss path length in corners significantly, so the impact of geometric cold bridging is reduced. I've been around with my thermal imaging camera and cannot see any temperature difference at all in any corners, the only place I can see small (around 1 deg C or so in very cold weather) internal surface temperature differences are around window and door frame edges, where despite my best endeavours there is still a greater amount of heat leakage than there is through the glazing. So it may well be worth doing 3D modelling for a poorly insulated house, but almost certainly isn't worth the hassle for a well-insulated one.

If I add the landscaping (so far, drive pavers, patio stone, turf, stone walls, fencing, stone and paved paths, raised beds, etc) then it increases the total by around £80/m². However, when we bought a new house there was no landscaping included other than just the paved drive, the path to the front door and the boundary fencing. We had to pay extra to get the garden turfed, a summerhouse base laid, paving laid around to the back door and a paved parking area alongside the garage to store my yacht during the winter. As sold, the house just had a sea of mud roughly levelled all around. On that basis, I think that it's only really the drive, essential paths and boundary fencing that should be included in the build cost.

That's a very good question! I used all the costs incurred, so included planning and BC fees, SAP registration etc, but we didn't use an architect or planning consultant so didn't incur those costs. I'm not at all sure what the calculators in the self-build magazines use. I suspect they may well use a lower figure, perhaps using just costs that fall within the VAT zero rate or reclaim rules, as those calculators often seem to be a bit optimistic to me.

Good point. Should be easy to do by setting a stop on the TMV (I've found that the one we have accepts the same sort of stops that are used on radiator TMVs).

For a conventionally insulated house (i.e. just meets building regs) then geometric cold bridging can be significant. The more corners you have on the outside shell the worse it gets.. It's not so much a major heat loss problem as one of creating cold spots in areas where air movement is already impeded by the geometry. One consequences is condensation and mould in these areas. The problem is that near an external corner heat flow from a single point on any surface ceases to be perpendicular to the wall, floor or ceiling, but has a mix of several heat loss directions; directly out perpendicularly, and at an angle out through the adjacent surfaces to outside. The result is a great heat loss from points near a corner than in the centre.

I added a note requesting a VAT receipt with every sizeable ebay purchase. 90% of the time I did get a VAT receipt from VAT registered suppliers, but the majority of ebay suppliers don't seem to be VAT registered, I found.