Jeremy Harris

Years ago I was on unusual management course (in that it was actually useful) and we had an exercise on decision making. We were divided into two groups and each group was given an envelope containing something that required a decision to be made within a set time. The groups were sent off to separate rooms, which included video recording. One group had to decide how many warheads the UK needed in order to be an effective nuclear deterrent. The other group had to decide on the ideal size for a garden shed. The group that had to decide on the size of our nuclear deterrent reached a decision well inside the set time. The group deciding on the size of a garden shed failed to reach a decision, and were still arguing when the time was up. The lesson learned was that big stuff is often much easier to decide on than small stuff. It's much the same with self-build. The big decisions, like deciding to buy a plot, are often relatively quick and easy. What soaks up inordinate amount of time and effort is making the small decisions, like what make of plumbing to use, or which tools to buy.

We had one at West Freugh. Favourite question to ask anyone who didn't know, was how much they thought it weighed. Not many looked at it and realised the damn thing weighed nearly 30 tons. Built like a brick outhouse, much like other carrier aircraft of that time.

Be interesting if it does apply to self-builders, as it opens up the opportunity to not have to pay VAT, perhaps, rather than have to claim it back on completion. This would seem to be sensible, as it would save admin effort by HMRC in collecting VAT that they only have to refund later. Mind you, common sense rarely applies when it comes to government, so it will probably never happen.

Yes. He had a connection to your neck of the woods, too, as he was one of the Buccaneer pilots who bombed the Torrey Canyon back in 1967, I believe. I think it was someone in Newton Stewart that reported him in the end, as he'd often do a few (limited) aeros over his own house, pretty close to the power cables.

He ended up getting into serious trouble for unauthorised low flying after I'd left, as I was asked if I'd be a character witness for his defence. I had to refuse, as I knew full well that he'd take any and every opportunity to break the rules. I've flown at a few feet above the water down the length of Glen Trool with him more than once. I had two Devons in the fleet at West Freugh, XM223 and VP959. Both were scrapped before I left (they ran out of fatigue life), and were replaced by a Jetstream, XX475.

I remember Basil, he was a friend of my Chief Pilot, Dougie (who lived in Newton Stewart), I think.

Sounds a good candidate for GRP. GRP is a lot easier to apply to a small roof, will last decades if applied properly and it's easy to get all the stuff needed, together with advice on how to use it. CFS (note: I've a relation that used to work there) are a good source: https://www.cfsnet.co.uk/acatalog/CFS_Catalogue__FLAT_ROOFING_21.html The only word of caution (apart from the need to ensure that everything is kept dry) is that the resin will attack EPS, so keep it clear of the un-rendered/clad ICF structure. It's no worse that the gun cleaner used for cleaning foam guns in this respect, though, so just needs using with a bit of caution.

I think we may have met at West Freugh, back in the mid-1990s. Are you the chap that wanted to do the initial test flights for a Europa there?

It's all about speed. Light aeroplanes don't have brakes in the air, so speed is proportional to approach angle. The landing speed (especially for a taildragger like the Chippy) has to be nailed accurately on the approach, and pretty much the only way you can bleed off a bit of speed and height is to side slip (as the Chippy does in that approach). That's really only for a bit of fine tuning, though, it won't get rid of the sort of speed that you'll get if the approach is too steep.

One thing to watch if thinking about making a recess (which seems a good idea) is that some alarms need room to side off sideways from the base and some (like the Kidde ones) need a screwdriver to be pushed into a slot in the base to release the unit. However, I think it should be possible to make a larger recess to allow access/release movement. Have you thought about wall mounting them? No reason why they shouldn't work pretty much as well when mounted high up on a wall as when mounted on the ceiling.

Sounds a good solution. My only concern without this would be an uneven point load being applied to the EPS during installation, before the window is sat fair and square down on the EPS. Putting a tray or pan on top of the EPS will remove that risk and probably make getting the window into place a bit less fraught.

That will just create a pretty high stress in the limited cross sectional area of the fibreglass tubes. What wall thickness are they? I can easily work out the bearing stress and see it it's within limits. I suspect it might be pretty high, as the CSA won't be very large. Area is your friend when it comes to situations like this. The higher the load bearing area the lower the stress in the material. The EPS will be fine on it's own, as it's well within the max allowable bearing stress for even EPS100. If you wanted to reduce the bearing stress still further then a bit of ply under the window, that's wider than the bearing area of the base of the frame, would spread the load. If it were me I'd just put the window on the EPS and have done with it. I have a left over L shaped EPS foundation block here, that's been outside for 6 years now, and which I've regularly used as a step-up. I weigh about 82kg, and the soles of my feet have a CSA of about 0.02m² each (assuming that they were dead flat - they aren't, as the tread pattern will probably halve this area). Each time I step on to that block of EPS I'm putting a bearing stress on it of about 40 kN/m². After years of being repeatedly stepped on and stood on there's not a sign of any depression in the surface. Your window is going to put a load that's probably less than 1/4 of the stress that my feet put on that block of EPS, and unlike me jumping up and down on it all the time, with luck your window's just going to be plonked on there once.

Bit like the dog-leg approach to 26 at Popham. You get used to it (eventually...).

Definitely not! The pressure on the bearing area would be colossal, as the screws are so small in cross section. The key is making sure the window is bearing on enough area to keep the pressure well within the allowable bearing stress of whatever it's sat on. A couple of large (say, 10mm diameter) screw heads would have a pressure on them, from a 450 kg window, of over 28,100 kN/m².

I think the pump may have a separate speed control wire, and that the relay is only used to turn the pump on and off. When standing next to the Sunamp PV when it was charging, it was noticeable that the pump speed kept changing, as the power output from the heating element changed (this was with excess PV charging). I think the pump they use has either a 0 - 10 VDC control signal or maybe a 4 - 30 mA one, a check of the pump model number should show which it uses.

The chances are that it will need a pretty high peak current to operate, something that a battery can happily provide, but which a generator or mains DC power supply might struggle with. Best bet might be to keep the battery but just charge it when you use it, so that it stays topped up. Even a fairly tired battery may still be able to provide a fairly high peak current.

That's how we did it. You can buy very long screws that are made for the job, often from the same places that supply sleepers for raised beds.

Welcome. My father had progressive, non-remitting, MS and we had to make a lot of alterations to our house so that he could remain at home. We built an extension downstairs, so he had wheelchair access to the bedroom, and converted the downstairs WC to a "drive-in" shower room, so he could be wheeled in for a shower. Those alterations were relatively straightforward, and the only thing I think would be different if doing it today would be to build in the strong points needed for a ceiling mounted hoist rail. The wheeled hoists aren't easy to use, and it often took both myself and my mother to wheel the thing across from his chair to the bed, and vice versa. The difficult alterations (which we didn't do) were the internal doorways and provision of wheelchair turning areas. The house had been built in the 1930's and had fairly narrow internal doors that were a tight fit for a standard wheelchair. Narrower chairs are available, but unless motorised there is the risk of knuckles hitting door frames (I have a wheelchair using friend who often wears knuckle protectors for just this reason). Turning areas are mainly a problem with something like a shower chair, which usually needs someone to manoeuvre it into place. The additional length of the chair plus person pushing/pulling it needs more turning space. We found that the local visiting occupational therapy department were very helpful in advising on modifications and the placement of handholds, etc. Probably worth getting advice from them whilst planning the layout of the extension. Finally, one thing we added to the extension that made life a great deal more enjoyable for my father was a wide access door, with a ramp that led out to the garden. Often gardens can be a bit inaccessible, and so those with limited mobility may end up being prisoners inside their own house.

Isn't that through-the-wall arrangement a heck of a nasty thermal bridge? I thought the most common arrangement was for the toby/water meter to be down a hole in the ground outside somewhere.

Yes, we did exactly this. We had a pole that was in the way, together with power and phone cables that draped over the plot and restricted what we could do with the big digger. The first stage is to identify who owns the pole(s). In our case, the pole belonged to SSE (had a sign on it, and was engraved with an SSE reference number) so I contacted SSE initially. They agreed to move the pole and allow the power cable to be re-routed underground, for an agreed price. Our ground works chap dug the trenches and laid ducting and SSE provided new power cable that was pulled through, then SSE turned up and placed a new pole in the corner of our plot, connected the new underground cables and removed the overhead cables. They left the 'phone cables on the old pole. I then called Openreach and had a real battle to get them to do anything. Eventually I got hold of the mobile number for the local engineer, who was great. He told me that moving the 'phone cables would be free of charge, as it was SSE moving their pole that had caused the need for them to be moved. He free issued Duct 56 and cable, I agreed to lay it all underground and he then tried to organise the removal of the overhead wires and the connection of the underground ones. This was a real PITA, as jobs like this are a very low priority for Openreach, so we waited weeks for them to do the work. In the end we absolutely had to have the overhead wire down, as it was holding up the build, so we were advised that if there was an "accident" on site that brought the wire down, Openreach would come out straight away to fix it. As luck would have it, the digger jib accidentally snagged the wire first thing one morning, and an hour later Openreach were on site connecting the new cables up... I then struggled to get anyone to remove the old pole, with SSE telling me it was their property, me telling them to get it off our land, and them ignoring me. In the end I slipped a few pounds to an Openreach Polecat crew who were replacing a pole in the village and they pulled the pole out and laid it down in our verge, where it now sits, staked in place, as a barrier for tractor tyres.

Yes, that's what the Sunamp controllers seem to do. The UniQ is a bit "all or nothing", in that it just turns the heater off when the temperature of the PCM, as measured at three (possibly four on the newer models) points reaches the target temperature(s). The Sunamp PV modulates the heat flow into the PCM using the variable speed pump in the charge loop, together with the heating element relay, so if the PV diversion unit is only sending a small amount of power to the heating element the pump slows down to increase the temperature of the water leaving the heating chamber.

I think there's an arithmetic error here: 400 x 9.81 = 3924 N 4.2 x 0.1 = 0.42m² 3924 / 0.42 = 9343 N/m² = 9.343 kN/m² (I rounded the result up to 9.35 kN to err on the side of caution previously) Given that the whole mass of our house is sitting on an EPS foundation, then I hope so! Seems well proven as a foundation material, as it's been used like this for a few decades. When I was looking into it I found examples of basements in Germany that had been built 30+ years ago with load-bearing EPS underneath them.

This sounds like a possible way that their scam works. I was struggling to work out how they could benefit if the credit card companies were refusing to handle their payments, but I guess it may well be possible to just use their website as a "man in the middle" data collection scam.

Joining metric to imperial always needs an adapter designed for the job. There's no way an old BSP imperial pipe will fit into a metric fitting. Even Philmac sell separate imperial alkathene to metric MDPE fittings, as a specific part. Their standard MDPE range are metric only. The fact that 3/4" alkathene (the nearest size to 25mm MDPE) has an OD of 26.6mm minimum, 26.9mm maximum, is enough to show that there is no way that an O ring sized for 25mm OD has a hope in hell of even being stretched over the pipe, let alone forming a reliable seal. I frankly wonder where you get your supposedly "expert" advice from. If I had to guess I'd say it was from people who don't know their arse from their elbow. FWIW, I've laid 100's of metres of 3/4" black alkathene over the years; it was the standard water pipe run around the farm for water troughs in the fields. The stuff is noticeably larger in diameter (and was more robust to handle, due to the thicker wall thickness) than the lighter weight metric MDPE we have have now.

Nothing at all wrong with Philmac fittings. I've used 3 or 4 different makes of MDPE fitting (bear in mind that we have loads of MDPE pipework, courtesy of having a borehole plumbed with the stuff) and my favourite is Plasson, but Philmac comes a close second. TBH, all MDPE fittings are much of a muchness, with the sole exception of the tat that Screwfix sell (easy to tell these from others, they use a lip seal rather than an O ring). The best online supplier I've found is Pipestock, but they are just down the road from me (well, a half hour drive away): https://www.pipestock.com/