Jeremy Harris

The thermal conductivity of a material doesn't change just because you add insulation to one side of it. The key thing here is how long it takes for heat to move from deep in the material to the surface and how quickly the surface can dissipate that heat into the house. The latter depends primarily on the temperature differential between the air in the house and the material; the former depends on the temperature differential and the thermal conductivity of the material. Once you reach the point where the time taken for heat to travel from deep in the material to the surface is greater than the diurnal fluctuation in temperature then it's effect becomes small, especially when you consider that deep inside an internal, well-insulated, wall, roof or floor structure the temperature is only going to have a tiny temperature differential compared to the house, and so heat movement will inherently be a lot slower than in a less well insulated house, where the air in the house may well have quite a wide diurnal variation.

What annoyed me was that I'd calculated the volume of crushed concrete needed to get the levels right, and when the firm quoted I questioned the cost of it (it seemed high) and they suggested I talk to their QS. Their QS is the one who seems to have cocked up, and if I'd had the confidence to stand my ground and get them to reduce the quantity to the figure I'd calculated things would have been about right. Sadly we couldn't re-use more than a couple of tonnes of it. In fact I have a feeling that when we come to plant the two cherry trees either side of the drive entrance we may well need to lose another tonne or so of it, as I'm pretty sure those areas still have a fair depth of it that will need to be dug out and got rid of, then replaced with (expensive) topsoil. The costs quickly add up with mistakes like this, paying for the stuff, paying to have it taken away and then paying again to have proper soil brought back.

As above, wait until the frame is up and finished, as the best solution for boxing eaves and verges will probably arise from looking at what you've got. We also used the Kytun aluminium verge, it really is very neat indeed, especially in black with slates. I looked at using aluminium for the rest, but ended up using black uPVC, as that meant I could use the thick structural (internally foamed) stuff and not need to use timber eaves and soffits and then clad them. It did sort of go a bit against the grain, using uPVC, but I have to say the finish is very nice and it was really the only practical solution for the 500mm deep soffit under the gable overhang (bearing in mind I wanted a maintenance-free solution). The downside with uPVC (and probably dark coloured aluminium) is the way it expands and contracts in the sun. There is a great deal of movement along the length of the house at the front (the South elevation) and although it doesn't seem to make any loud noises, the gutters do "walk" a lot. I ended up fitting tiny stainless self-tappers either side of the gutter joints, to stop them constantly being pulled apart. On one occasion, one section of gutter had shifted around 100mm one way, just from gradual expansion and contraction every day. Mind you, uPVC expands around 2.5 times more than aluminium, so is probably more of a problem when it comes to movement.

Been there, done that, in our case it was the hardcore for the temporary access, that was supposed to end up as the drive base later. Last day of the work, the ground works chap chucked in tonnes more than was needed and couldn't compact it to the right level, then walked off the job and invoiced me for the final stage payment before I'd noticed that the access was far too high. The first truck that tried to get up it (a skip lorry with an empty skip), really struggled and rutted up the surface badly. I had the foundation team coming in at the start of the following week, who needed concrete truck access, so I hired a minidigger for a day and started digging out and relocating the hardcore to one side. It took me a whole day and in places I dug out a metre in depth and still hadn't reached the terram that was laid under it! It was supposed to be a 200mm thick layer, graded to the levels on the plan. Later, when we put in the drive drainage crates and laid the proper drive we had to take out around 170 tonnes, a fair bit of which was unwanted crushed concrete that the main ground works contractor had laid in excess. At a guess I reckon there was a good 30 tonnes too much, around two tipper truck loads.

70 to 80 deg C is OK, anything lower than about 60 deg C and the big single cylinder Lister will start to soot up, more so when run on WVO. A big thermal store is a must, as is a switchable thermal dump for when you need to run the genset but don't need the heat (in summer, for example). The chap in the next village has his Lister, biodiesel manufacturing kit and WVO store in a concrete block house half buried into the hillside (it was the old air raid shelter for his house). He runs hot water from there to a big thermal store in the house and has a thermostatic changeover valve that switches two large radiators on in the cooling circuit when the thermal store is up to temperature. One of these is inside the blockhouse, with an external opening panel to let the heat out in summer, the other is painted and fitted to the outside wall. One thing he found was that he needed to restrict the primary flow around the engine, so that he could run the engine at a near-constant 80 deg C or so, irrespective of the thermal store temperature. I can't remember how he has done this, but have a feeling he uses a bypass system with a car-type thermostat to keep the engine hot all the time. I do know that the thermal store primary only runs on a thermal syphon, even though there's a massive pipe run, and that seems to work fine. IIRC, his big Lister can provide around 5 or 6 kW of heat into the water when it's running under load, and seems to be able to heat his fairly old (I'd guess 1930's) three bedroom house OK, although he has added insulation and does things like fit sheets of PIR foam board over unused doors and windows in winter (he lives on his own.....................).

There's been some work done (I think by the BRE, but it might be someone else) that shows that for normal masonry building materials thermal conductivity limits the effect on the thermal time constant in practice. The general rule of thumb is that anything more than 100mm below the surface doesn't have any significant impact, because heat flow is so slow by the time you get down to 100mm that it can't have much of an effect on regulating the temperature of the house. This means that with insulation outside the thermal store created by the structure, there's not any significant merit in increasing the thickness of the internal structure above about 100mm, assuming masonry construction.

On the other thread there was a diversion about planning politics. I wrote this: ProDave replied: I replied: and then Ferdinand added this: The 106's were agreed on all three. What has happened on two of the developments is that the access, services and infrastructure have been put in, but no houses are being built. Presumably this has been done to lock in the PP. The third development has been sat with no work being done at all, 18 months after PP was granted and the 106 was agreed. The developer was forced to reduce the housing density on that one, and the local view is that work is going on to get a more application in for more houses on the plot. It's caused some ructions, as two of the most vociferous supporters (in a village that was overwhelmingly opposed to the development, just because it's in a stupid place, on a very steep hill) did so on the basis that they had children who were getting married and looking for somewhere to live in the village, so the "affordable homes" in the development we looked at as a way to achieve that. One of those former supporters has now bought a small infill plot and gained planning permission for their son to build a house and work started about 6 months ago, so that's one less customer for this developer.

Our neighbour has one in their extension. It's forever getting damp with condensation inside, that on bad days drips down inside the house. The problem seems to be that the outer dome gets very cold, and warmer, moister, air from inside can get inside the tube, then condense on the dome and run down the sides. I doubt it's even vaguely airtight, and most probably isn't that thermally efficient, either.

Under conventional pavers it's sharp sand. That under permeable pavers is very coarse sharp grit, 2mm to 6mm very sharp edged stuff. It tends to take time to fill the slots, even after having been brushed and whacked, hence the reason for needing to re-apply it a couple of times. I can take some photo's next week of the grit, as I still have a couple of bags left by the chap that laid it, as we've not used it all on re-filling the gaps. The gaps in the permeable pavers are around 5 to 6mm wide, hence the use of the very coarse grit. Drainage under permeable pavers is totally different to that under conventional pavers. It's essential that the sub-base is type 3 (10 to 30mm no fines) so that it's free draining, with either perf land drain pipe or HD aquacells underneath, as we have, to take the run-off. This keeps the grit dry and so stops weeds from growing. Our previous paved drive was on sand, and I was forever going around with weed killer, as the sand would stay just damp enough to allow weeds and grass to germinate in the gaps, but this doesn't happen with the coarse grit.

Getting ESP to admit that the Ecocent is really a Chinese imported unit that they have had properly CE tested and stuck their badge on is not easy, but I'm damned sure that's exactly what it is, anyway. I looked very closely at the original and the Chinese vendor sent me a stack of technical information and photos and it was absolutely identical in every way to the Ecocent. The snag is that these are all constant power devices, they do not have inverter drive and so are either full or nothing (the same is true of the Ecocent). This means that you have to accept the full power (a couple of kW) and then store it in a buffer to prevent short cycling. They are pretty well made, at least the data from the Chinese ones I was sent seemed OK, but pretty basic in terms of controls, just a relay control board to switch things one and off, with a conventional motor starter on the compressor, no form of variable speed control. Temperature setting is easy, the in-duct units have a threshold water flow temperature (just a simple thermostat) and you can set this to anything you want. Turning it down will probably make the unit short cycle, but with an input power of around 400 to 600 W I'm not sure that's a significant issue. A better unit for just supplying this sort of output would probably be one of the Spanish/Portuguese direct collector heat pumps, with the plate heat exchanger(s). There's a dearth of decent information on them, most probably because they were designed for use in a warmer, drier, climate than the UK, and there have been reports of them icing up when used to provide hot water at 50 to 60 deg C here, but I'm fairly sure they could be turned down to a lower temperature and run ice-free. They have the big advantage of not having a fan on the external heat exchanger, it's just a black anodised aluminium plate affair.

Ours has been down 2 years. No problems at all. The heavy rain this week was a good test and we had no run off at all. I suspect what you saw was a badly laid area. If laid with sharp grit, and if the grit is re-applied a couple of times over the first few weeks, and brushed in as it settles, then you don't get dirt build up and it most definitely doesn't puddle. The chap that laid ours was insistent that we'd need to brush more grit in a couple of times in the first few weeks, and left a bag of grit behind so we could do this. It all comes down to how well the stuff was laid and whether or not the MI's were followed to the letter, I suspect.

They should, but they didn't, in any of the three cases. It's a game, with the prize being the uplift in value of the land with time once it has PP. I know things are very different here from where you are, but we're in a rising market with a housing shortage, so controlling the release of new houses to the market controls the price, which in turn controls the profit.

Good news, but I'll be very interested to hear how long it takes before the developer ACTUALLY STARTS BUILDING! My experience around here is that I've now sat in on three planning committee meetings, where big developers have put forward strong cases for gaining planning permission, always on the basis of the URGENT need for new houses in the area, and that the Local Authority was failing to meet its deliverable 5 year housing target. The last one of these was 18 months ago. So far NONE of these developments have even been started..........................

I've split this off so "hoarding" can be discussed here:

The registration of all private sewage treatment and disposal systems was supposed to be mandatory years ago, there's some EU rule requiring that these all be converted to EN 12566-3 2005 compliant units (eventually). The first stage was supposed to be registration, so that there was a record of every system. That would then allow the EA/SEPA/NIEA to police them and ensure that all were converted to proper treatment plants (eventually). For a host of reasons (mainly because it's a Herculean task and the agencies don't have the staff, as I understand it) registration was only mandatory for a new system, but even that isn't complied with, as often only new builds will have any means of being able to enforce that, through building control. I am sure that, sooner or later, registration and the conversion of all existing systems to proper EN 12566-3 2005 certified ones will happen. There's only so long we can hold off on what is supposed to be an EU-wide set of rules. I have wondered how on earth they propose enforcing this in places like France, Italy, Spain or Greece - if anyone has ever wondered why some rural Greek toilets have a "no paper down the toilet" rule it's because there is no treatment at all, just a hole in the ground (or more often rock).................

The concrete around a treatment plant is to anchor it and stop it floating out of the ground, not to support it, so hard ground doesn't negate the need for a ground anchor if the area around the treatment plant is likely to get saturated with water. We fitted a concrete anchor ring around ours to stop it floating up, as per the manufacturers recommendation. They can (and do) float out of the ground, as when only partially full (as would be the case with a long neck extension) there can be a few tonnes of buoyancy, and that can easily float a tank or treatment plant out of the ground. I have some personal experience of this, as we buried a Klargester "onion" septic tank on a farm in Cornwall years ago. We just put pea shingle around the thing and backfilled the hole. A week later it had broken free and was sitting on top of the field, just like a damned great orange mole..............

Are you sure about the pea shingle? The MIs for our permeable pavers specifically mention not using any rounded aggregate at all. The sub-base is clean (no fines) Type 3, wacked in layers, then the bedding layer is 6mm to 2mm sharp grit. The MIs are absolutely clear that it has to be a sharp grit, as this locks together and holds the pavers securely. They warn that using pea shingle or similar will result in instability, which I can understand - it's be like laying blocks on ball bearings. I found the invaluable "Paving Expert" site to be a mine of useful information of SUDS and particularly of laying the paving: http://www.pavingexpert.com/permeable04.htm I needn't have worried, though, because the chap that laid our drive had done loads of them using the same pavers and so was a dab hand at doing it.

You could, but as an experiment you'd probably find buying direct from China will be a lot cheaper and give you some options that are better suited to this application. These units are extremely popular in China, with seemingly dozens of companies making near-identical units, including the stand-alone ducted air to water heat pump box, which might well be better suited for something like this. I did a fair bit of research on these years ago, when I was seriously considering using either the Ecocent or the stand-alone heat pump box, and it seems that there are still loads of them available at reasonable prices. Here's a few of the very many Ecocent-like units: https://www.alibaba.com/product-detail/Air-source-heat-pump-250l-hot_60365500444.html?spm=a2700.7724857.5.16.k0LV15&s=p https://www.alibaba.com/product-detail/All-in-one-Heat-Pump-Water_275220833.html?spm=a2700.7724857.29.12.k0LV15&s=p https://www.alibaba.com/product-detail/Air-ducted-all-in-one-heat_725212021.html?spm=a2700.7724838.0.0.jfQhch https://www.alibaba.com/product-detail/Alto-AHH-R030-20-quality-certified_60411875790.html?spm=a2700.7724857.29.94.k0LV15 https://www.alibaba.com/product-detail/floor-standing-300L-air-source-heat_60235887069.html?spm=a2700.7724857.29.110.k0LV15 https://www.alibaba.com/product-detail/Air-source-heat-pump-water-heater_673442048.html?spm=a2700.7724857.29.308.k0LV15 and here's a couple of the ducted heat-pump only units: https://www.alibaba.com/product-detail/Hot-water-heat-pump-with-circulation_1227070644.html?spm=a2700.7724838.0.0.yt9man https://www.alibaba.com/product-detail/Air-Source-Heat-Pump-Water-Heater_60220362423.html?spm=a2700.7724838.0.0.jfQhch I found that a few of the Chinese manufacturers were surprisingly helpful, with one even offering to give me a sample of a unit that looked absolutely identical to the original Ecocent (except the label) for just the cost of shipping, if I would review it and write up an English description. I was more interested in the small ducted air to water heat pump unit, though, as it seemed that it could potentially be more versatile, albeit at a slight loss in efficiency (pretty much all the tank-top fitting units I looked at had a direct refrigerant to tank heat exchanger unit, so don't have a water circulation circuit).

This is just a very poorly educated BCO, who isn't familiar with the agreements that allow acceptance of certification between UK and RoI, agreements that have been around for decades. The Kore Passive Slab system (which is the system MBC use) is detailed here: https://www.kore-system.com/kore-products/floor-insulation/kore-passive-slab/what-is-kore-passive-slab and has even won BRE (Building Research Establishment) awards. It has NSAI accreditation for below ground, load bearing, use and there is a formal reciprocal agreement under which the UK accepts NSAI as if it were BBA, and vice versa. The same applies to engineering qualifications. A chartered structural engineer in RoI is considered to be a chartered structural engineer in the UK, again under a reciprocal agreement about qualification standards that's been around for decades.

If I can find it I'll dig out the model I did. It was a long time ago, as the debate was over on the GBF, so long before we'd pinned down the detail design for this house. The main summer benefit is the massive increase in ventilation rate if the unit is connected up to an MVHR. It increases the whole house ventilation rate (in our case) by a factor of four or five, IIRC. That then massively degrades the MVHR heat exchanger performance and was the major cause of increased winter heat loss. As you say, not a problem at all in summer, as the air outside is plenty warm enough most of the time, plus there will be solar gain. I've been surprised this week to find our house hitting 23 deg C (the point where the cooling system kicks in) even when it's only 16 deg C outside and it's heavily overcast. I measured the outside of the front window frames and they were about 30 deg C, a surprising amount of solar gain given the conditions.

Be interested to see how this goes, as the physics are straightforward; if you take a couple of kW of heat out of a house to heat hot water than somehow that couple of kW has to be replaced, or else the house will cool down. The bottom line is that the heat has to come from somewhere, so unless there is "spare" heat coming from somewhere, then additional heat needs to be added to compensate for the heat taken from the house to heat the water. In a well-insulated, airtight, house, then the effect of taking even 1 kW of heat out is, without a shadow of doubt, noticeable in cold weather. If I take around 1 kW of heat out by turning on our Genvex in cooling mode it's extremely noticeable in winter, but barely noticeable at all in summer, when there are far lower heat losses and a fair bit of solar gain, even on cloudy days. I remember discussing this at length with someone who had an Ecocent and his findings were the same, except he had a sun-heated glazed porch that collected heat and, IIRC, an air feed from a workshop with a wood burning stove to supply the additional heat that the Ecocent was removing from the house. I modelled the performance of using one, with great help from the ESP people, but just couldn't get the sums to add up for our house, with it's low overall energy needs and high sensitivity (especially in cooler weather) to changes of even a few hundred watts in heat input/output. The flip side is that I know a chap who lives a few miles away, in an older house with wood burning stoves and a Rayburn and the Ecocent works very well (apart from a corroded stainless cylinder - which was something amiss with the protective anode IIRC). It works well because a couple of kW is a negligible change to his overall heating requirement.

My guy spent around half a day just sanding what was, to me, a perfectly flat and clean plaster surface. He had a neat long-handled sander to get right up to the tops of the walls and sand across the ceilings without needing a ladder etc. I don't know how the spray guys do it, but our bloke put an initial coat of slightly watered down white emulsion everywhere, and let that soak into the plaster and dry off. He then lightly sanded that and rollered the first top coat, lightly sanded that and rollered on the second top coat, with the other chap going around with a brush cutting in the corners and around the windows and doors. I provided all the paint, filler and the access tower, and paid £1200 labour to do the above to all the internal walls and ceilings on our 130m2 house. I can't remember the total area painted, but it was greater than that for a "normal" house of that floor area, because of the 4m high vaulted ceilings upstairs.

Pre-EU, the roads in RoI had a blanket 50 mph speed limit, IIRC, but to be frank, you couldn't have done 50 on any of them anyway. I used to drive over to the West Coast a fair bit in the late 70's/early 80's, and the trip from Dún Laoghaire across to Clare could take all day. "Main" roads back then had a yellow line marking the left hand lane and were just about three lanes wide. The left lane was for horse drawn traffic and tractors, not cars, so you drove down the centre, pulling over to the left if there was anything coming at you or if you saw someone coming up from behind who was mad enough to want to overtake. The contrast with my most recent trip over, where the trip from Dublin down to Cahir only took a couple of hours on a good motorway, was remarkable. What was less wonderful was a drive up from Rosslare to North Antrim about 15 years ago, where bloody awful white rendered bungalows were being built all over the place, because of the lack of effective planning controls. It seemed that, with the boom in the economy a good number of people were just building a new house in the field alongside their old one. The town land where my grandmother was born and grew up is now a mix of old longhouses and pretty dire modern bungalows, not the place it was 30 years ago at all. Many of the houses built during the boom were pretty shoddily put up, too, hence the clamp down on building regulation and enforcement in recent years.

I've no intention of treating it for the next 20 years or so, based on advice from the chap at the local sawmill. He reckons it should be fine for 20 years or so without treatment, then maybe use a clear preservative every few years after that. We quite like the weathering and anyway the planners wanted it untreated (or more specifically the conservation officer). Our larch was very garish when it was fresh, with a very red/orange look, that attracted a few adverse comments from people!

By accident (because it was available at the right price, as surplus new stock) I bought a 7 kw inverter controlled heat pump, even though I knew our house would never need more than 2 kW of heating at the very most. It has proved to be an excellent match to our needs, as when at low power levels it seems to be extremely efficient, primarily because it rarely, if ever, defrosts. The other benefit is that when running at these very low outputs it is extremely quiet. ST here has stood next to it when I turned it on to illustrate the noise, and can attest to the fact that it's hardly audible above the background noise. The MVHR air intake, high up on the wall behind the ASHP, is noisier, although even that isn't as noisy as a normal extractor fan.