Jeremy Harris

You can work out the sums very roughly. Take the area of the ground floor, multiply it by a given ground bearing load in kN/m2 and then divide the answer by 9.82 and that gives you the total weight of the house, but you have to factor in a reasonable margin for safety (typically a number between 2 and 3 I think - I don't have the relevant Eurocode to hand to say what the margin is for a load bearing slab foundation, but doubt it would be higher than 3). Say you had a ground floor load bearing slab area of 100m2 and you are working to a margin of 3 and your ground has been compacted and tested to a max allowable bearing load of 40kN/m2 . 100m2 x 40 kN/m2 = 4000 kN max allowable load, divide that by 3 (the margin) and you get a max allowable total ground bearing load of 1,333 kN. Divide this by 9.82 and that gives the max allowable weight of the house, including all dead and live loads, of 135 tonnes. Our 130m2 one and a half storey timber frame house, with pretty heavy cellulose insulation, weighs around 40 tonnes. If it was block and brick construction it might be something like 50% to 70% heavier. Hopefully you can do some rough sums and see what sort of load your house is likely to put on the ground. Remember to allow a reasonable margin, say 2 or 3, just for safety.

There's a post here somewhere where I calculated it, remembering to allow for the 45 deg outward spreading zone, that increases the effective bearing area. Off the top of my head I thing the total house bearing load on the ground was somewhere between 2 and 5 kN/m2

Just for info, I had a 3m wide Seceuroglide "insulated" roller door fitted to our garage. The foam-filled alloy slats are a joke in terms of insulation - the foam may as well not be there for all the good it does, as it's only about 10mm thick. Not really a problem in Winter, rather surprisingly, but a hell of a problem in Summer, as it faces south and the inside of the door gets too hot to touch when the sun's out. The garage gets like an oven and I've plans to add a heat reflective curtain. I did an initial trial with multifoil (yes, I know, but I couldn't think of anything else that I could easily make roll up as a secondary internal roller) and stapled some thin multifoil up across the the garage rafters to test how well it worked (it's floored out as a storage area). I can confirm the standard thin multifoil stuff is totally useless, as the loft space stays as cold in Winter and as hot in Summer as it ever did. I'm currently having a re-think as to how best to insulate inside the roller door. Needs to roll up, ideally, as I don't want to take up space with sheets of insulation.

We got some additional funding by mortgaging our existing house, which at the time was mortgage-free. I found there were only a few lenders who would offer a mortgage in order to put the funds towards building another house, and that of those that did, the maximum LtV was 50%. That may have changed a little in the last few years, but it's worth doing some research on what different lenders may offer - we were let down very badly at the last minute by Santander, for example, who offered us a mortgage, completed all the paperwork, took the fees etc, then withdrew the mortgage offer on the day I went in to draw down from it. Cost us a lot of money and caused a great deal of hassle.

Just checked on differences between English and Welsh regs re: timber frames. They are the same, AFAICS, even down to referring to the same standards. So what's been approved many times in England will be just as legal in Wales. Sounds like your BCO is in the dark ages; might be an idea to just get another building control company to do the approval and inspections, rather than try and deal with an awkward one.

There are small noggins connecting the inner and outer frames, but they are relatively long, surrounded by insulation (so can be considered to be 2D thermal transmission paths) and make up such a small part of the overall wall area that their effect is very small. It's a system that was first invented as an "add on" for conventional timber framed houses by a chap called John Larsen, in Canada around 30 or more years ago, and such walls are often referred to as Larsen truss walls. Others here have done various forms of DIY insulated raft - not that hard to do, as several people have come up with ways to get around having to use the EPS/XPS pre-forms for the edges, and fabricate them using EPS sheet.

Thanks for that, I'd assumed that building regs was one of those things that hadn't been devolved to the Welsh Assembly, but hadn't checked to be sure.

No problems at all with BC - take a look here and you can see all the documents I submitted to them for approval: http://www.mayfly.eu/2013/09/part-fifteen-the-site-is-finally-ready/ The building regs are the same in England and Wales, AFAIK, it's only Scotland and NI that have slightly different regs, so there should be no problem at all with using this system in Wales, AFAICS. The massive benefit over a single studd is that there is no thermal bridging plus you have 300mm of relatively high decrement delay insulation filling the entire wall - makes a significant difference to the comfort of the completed house I've found, it tends to be cool in summer and warm in winter, due to the decrement delay primarily.

If you want chapter and verse on the variations of the Kore design for different forms of construction, this booklet covers most of them, including conventional block and brick cavity wall: http://www.mayfly.eu/wp-content/uploads/2017/12/Kore-Insulated-Foundations-Report.pdf

It hasn't ever done so in our case, and I've had floor cooling set up and working for a couple of years now. Although the flow into the UFH is typically around 10 to 12 deg C, the floor surface has never yet dropped below 18 deg C, and to get condensation on the floor surface at 18 deg C with an air temperature of 22 deg C would need a relative humidity of a bit over 78%. Currently the house RH is sitting at 44%, so way out of the condensation risk zone. To get condensation on the floor with a 22 deg C air temperature and 44% RH would mean cooling the floor surface to just over 9 deg C. I have found that the UFH manifold sometimes gets some condensation on it, so have rigged up a plastic drip tray underneath is. So far I've never seen any water actually drip into this though, so assume that it evaporates away.

The outer skin on our house is larch cladding, so doesn't sit on anything. The twin stud passive frame sits with the inner structural frame on the reinforced concrete ring beam, then the outer, non-structural frame rests on the DMP that's wrapped over the 200mm wide EPS upstand. The big advantage is that the under floor and wall insulation become contiguous, as the hollow walls are pumped with cellulose that sits down on the EPS upstand, with no thermal bridging at the wall/floor junction. I don't know the slab cost, as it was included in the foundation and frame package, but the weathertight insulated frame and foundation, including the UFH pipes but excluding the windows, doors, slates or external cladding came to around £415/m² (bear in mind that this was nearly 5 years ago now and prices have increased a fair bit).

I think it's absolutely impossible to give any specifics about the ratio of plot cost to finished home cost, given the absolutely massive disparity in one-off plot costs across the UK and NI. In many areas it's often as cheap to buy a house and demolish it, just to get a plot, as it is to buy a building plot. That's not untypical around here, where plots under around £120k just don't exist (and at that price they will probably be a tiny infill closely packed between other houses). Many around here end up paying between £150k and £200k for a pretty average plot - that's just the reality of being in an area that's within the London commuter belt. The flip side is that in some places you can buy a really nice plot for between £50k and £100k, if you don't mind being in a more remote area. Likewise, the "rule of thirds" gets blown out of the water in some areas. Developers around here work on a margin of between 8% and 10% profit, well over 1/3rd of their cost being the plot. Other areas I know are different, and developers can still make substantially more, in % terms, per house, but less overall because the sale prices are lower. We looked at several areas when plot hunting, and found very substantial local price differences, often over a relatively short distance. For example, plots on the Bristol to Gloucester side of the Severn were generally a great deal more expensive than those on the other side of the Severn - it wasn't unusual to see a like-for-like differential of well over 50% between one side of the river and the other. Likewise Cornwall has some really daft plot prices, higher even than here in West Wiltshire, and when we were looking around down there we concluded that the cheapest way to buy a plot was to buy a house and demolish it - at a guess we'd have paid nearly double for a plot that was similar to ours. Each of us can argue a point from our own experience and location, but none can really offer a solid formula for the relative price of the plot, the house construction etc as there are just far too many regional variations, without taking into account the many other variables that impact on build cost.

+1 to @ProDaves comment about a passive slab. Loads of advantages, like you can integrate the insulation under the raft, fit UFH pipe inside the slab, powerfloat the slab to get a ready-to-lay-flooring top surface, plus it's dead quick. Ours took four days to put down, from the start to the power-floated finish, including all the UFH pipes (see here: http://www.mayfly.eu/2013/10/part-sixteen-fun-and-games-in-the-mud/ , although the last photo there was taken before the slab was power floated dead flat and smooth).

Depends on the volume, as much of the cost is the installation. I believe that warmcell and the like as materials are comparable in cost with rock wool, but it's the installation that pushes the cost up. Having said that, I believe that cellulose is far better for a roof, in particular, as the higher decrement delay over rock wool is a very definite advantage. If we're going to have more weather like that we've been having recently, then I reckon a lot more people are going to focus on decrement delay than overall U value. Right now I'm exceptionally thankful we went for cellulose. We were over working on some fencing yesterday and the house stayed below 21.5 deg C all day, with no cooling on at all, and the outside temperature peaking at around 30 deg C in the early afternoon. That's almost entirely down to the long thermal time constant of the house, and a fair bit of that is down to the relatively long decrement delay of the cellulose insulation.

Pumped cellulose might be a good option. Relatively high decrement delay, tends to fill every nook and cranny well, the only downside is needing the machine to pump it in.

I've found that my prescription (free for me here, too) isn't that great, as it's for varifocals and there is a compromise for the reading distance part. I keep meaning to just get two or three identical pairs of cheap reading glasses of different strengths, with the aim of seeing whether or not I can easily swap lenses over, as it seems I need a greater strength in one eye than the other. All the cheap pairs seems to be the same for both lenses - just need to find out how easy it is to swap lenses over.

I find that as well as a magnifier/reading glasses, I now need a lot more light to see close detail than I used to. I've been doing some watch repairs recently and found that a loupe with built in LED lights has been been a tremendous advantage. It throws bright light right where I need it, directly on the area being magnified. I was as pleased as punch at completing the restoration of my Father's retirement watch, one of the first electronic (non-quartz) Rotary watches from 1969, the day before yesterday. It's now looking almost like new, and keeping reasonably good time, after a couple of days of painstaking work stripping, cleaning and reassembling it. We found it up in the loft of my late Mother's house, when clearing it out a couple of weeks ago, and I suspect it had been sat in a box since my Father died in 1972. I was amazed that the battery hadn't leaked and corroded after all those years, and equally amazed that I could buy the correct battery for it 49 years later. It's on my wrist now, as we're off to the pub for lunch...

I've reset and calibrated levels a few times after they've been knocked. Not hard to do, but they all have some means of adjustment, often shims. Easy to calibrate with an end over end check. If the box section gets bent then you're screwed, but general knocks throwing them out can usually be fixed without too much hassle.

Only 368 times? Is that a lucky number? Or, perhaps, one that ensures the right balance between ying and yang, so ensuring that the bathroom has the right feng shui?

Probably not, I suspect, as I have a feeling that they will only increase a mortgage for specific items. Worth asking, and it'd be helpful if they said yes!

It was a false alarm. The reaction does not give off CO at all, but CO sensors are not very specific and will respond to other gases. In this instance there may well have been a very, very small release of hydrogen, most probably not as pure hydrogen gas, and the sensor responded to that with a false alarm.

I'd second this. We got caught out and lost several hundred pounds of VAT as we didn't notice that the "supply and fit" of the worktops was included in the "supply only" invoice for the kitchen, and we couldn't get the invoice corrected later. Thankfully this wasn't for all the stone, as we added the upstands and window cills later, and these were on a separate, zero rated, invoice. Still very annoying, though.

The new building that was built at Porton as a part of the rationalisation programme I managed in my last post, used a mix of glass and metal slat brise soleil screening. there was a lot of glazing on one office elevation and the screening helped a great deal to reduce the cooling loads. It's government policy to avoid the need for comfort cooling in all new buildings, as well as reduce the heating demand, which is one reason this was designed in. Clear glass was used for the canopies, and that seemed to work very well. IIRC, it had a very faint greenish tinge, probably just from the thickness and size of some of the glass sheets used (they were very large).

On the topic of overhangs, because "normal" glass has a high emissivity, it will absorb a lot of heat when exposed to long wavelength IR from the sun and get very hot. This means that glass external sunscreens can work very well - they will absorb the heat from the sun but let the light through, so as long as the external sunscreen has a gap between it and the house it will work just as well as any other sort of external shade. Glass canopies are an option, perhaps. Not massively expensive, won't reduce light levels, tend to look OK on a fairly contemporary house design and can be easy to fit.

AFAIK, Internorm don't make glass or glazing units, they will fit whatever meets the spec they need, so probably either Saint Gobain or Pilkington. Saint Gobain do SGG Planitherm Total + that is very similar to Pilkington Solar E, and is available as a low external emissivity laminated glass. The whole argument being put forward against external films seems based on fake science to me. This is the second summer we've had external low emissivity coatings on our glazing and my contact thermometer always shows that the surface temperature, inside and outside, of the glazing with the low emissivity film is a lot lower than it is for the glazing on the same elevation that doesn't have the film. The temperature differential between the internal and external faces is also always lower for the glazing with the film on, so any thermally-induced stresses in the glass must be lower. I'm convinced that the manufacturers simply haven't conducted long term tests on the specific glazing system you have, and so are just covering their backsides by saying "no", even though they know it's completely illogical.