Jeremy Harris

Welcome. You're quite near us, and we were down within spitting distance of you a couple of days ago, ordering some more trees from Landford. You're welcome to pop in and have a look at our build if you wish. We're a bit North and West of you, outside the National Park but inside the Cranborne Chase AONB, plus we have a listed building opposite and are in a conservation area, so we ended up having to jump through almost as many hoops as if we were in the park.

I think you need the automated version, perhaps:

We had about 12m² of external heat reflecting film applied two or three years ago, at a cost of about £100/m². It was a mix of Solargard and 3M Prestige. It works very well at reducing solar gain, and made a significant difference to our need for summer cooling.

The cost to watertight depends a bit on the build method. For example, some methods (like ours) would include the insulation and airtightness in the erection to watertight stage, whereas other build methods might literally be a bare shell with just the roofing, doors and windows fitted at that stage. Ignoring the site-specific ground works costs we had, which were really just knocked off the price we paid for the plot anyway, then the cost (excluding the plot cost) to get to the watertight stage (including insulation and airtightness testing) came to about £650/m², so a bit under half the final build cost. I've no doubt that some may well get to the watertight shell stage for less than this and some maybe more, as there's a fair degree of variability. There's also a scale factor to take into account, in that a fair bit of the cost of some work is tied up in things like mobilisation costs. For example, crane hire for lifting a timber frame, or glazing, will be much the same for a small house as it would for a large house, so the cost per m² of this for the large house will be a bit less. The same goes for stuff like transporting diggers, or scaffolding, and pretty much anything where there is an initial overhead incurred to get something to site.

We paid £1,400 (no VAT, labour only) for first and second fix for a 130m² house, with me supplying all materials and doing a fair bit of the labouring work. The breakdown was £700 for first fix labour, £700 for second fix labour. This was at 2014 prices, though, and I know that the chap has since put his rates up by about £20/day. The time taken was roughly 4 1/2 days for first fix and the same again for second fix, inspect and test. Smaller jobs are always disproportionately more expensive, as there is a fixed overhead for travel etc that probably makes larger jobs seem cheaper, in terms of cost versus number of switches/outlets..

The price per m² is always based on the gross internal floor area, not the footprint. For example, our house has a footprint of ~85m², but the ground floor area is about 76m² and the first floor area is about 54m², so the area for costing the build is 76m² + 54m² = 130m² (our first floor is smaller than the ground floor as the house is a 1 1/2 storey design). A 2 storey house of 270m² would have a ground floor area of about 135m² and a first floor area of about the same. The footprint would be larger than 135m² as it includes the thickness of the walls. £2,000/m² would be pretty typical for a house built by a main contractor, with you being fairly hands-off. The more work you do, the cheaper it gets.

It very much depends on your needs. We built a fairly large 2 bedroom house (~44% bigger than our old 3 bedroom house) because we wanted more space in the ground floor living area, specifically a reasonably sized kitchen, dining room and lounge, plus a utility room and room for each of us to have as a study. We ended up with two pretty large bedrooms, with a walk-in wardrobe and two bathrooms upstairs, plus a fair bit of "wasted" space in a 6m high entrance lobby. We could have squeezed a 4 bedroom house on to our house foot print, as the original plans that came with the plot were for a 3 bedroom bungalow. This site gives some rough areas for new builds: https://www.dwh.co.uk/library/Average-UK-house-sizes/ They reckon that an average 4 bedroom detached house is around 147m². I would guess that may seem a bit small for those looking for bigger bedrooms (and it will usually be bedroom size that suffers the most as house size decreases). 180m² to 200m² might be a reasonable aiming point for a fairly spacious 4 bedroom house, it very much depends on your budget and the nature of your site. The latter almost always dictates the house layout and design more than anything else.

Ours was timber frame, and block and brick may be slightly cheaper, but there isn't a massive amount in it. Most self builders who only do some of the fitting out work themselves tend to come in at around £1000 to £1500/m² I'd guess. Those who choose to do almost all the work themselves can come in lower than this, those who opt to use a main contractor will almost certainly come in a fair bit higher. The average size of house in the UK is about 90m². The average 4 bedroom detached house would be about 140m², perhaps a bit less on a newer estate. A fairly spacious 4 bedroom detached, developer built, home might be around 180m² or so. Anything over 200m² tends to have more bedrooms as far as developer built homes go, although self-builders may well do as we've done and forego additional bedrooms to make the rooms larger (our build is 130m², but only 2 bedrooms). Older houses tend to be bigger than newer houses as a rule. 270m² is fairly big for a 4 bedroom detached house, perhaps 100m² or so larger than a decent spec 4 bedroom developer built house. Not that unusual for a fairly high end self build, though.

I've lost the meter isolator having switched to an E7 meter, as that doesn't have one either. It's a great shame, as that screwdriver operated isolator seemed to be a very useful thing to have. Although I have an isolator on the tails that feed the SWA run into the house, I didn't think to fit one in the supply to the small CU that runs the outside stuff;it just didn't occur to me that the E7 meter wouldn't have one. Now I'm tidying up the installation and getting rid of the old temporary site supply box, with its commando socket, I'm going to have to pull the fuse to fit new tails to the Henley. Luckily the SSE meter guy was helpful, and left me a few spare seals and wires.

The number of supposedly trained electricians who seem to baulk at working on a CU that has live connections (as they almost all do with the cover off) seems to be growing, if some of the forums are anything to go by. It seems the (mainly good) emphasis on checking that stuff is dead before working on it is now being taken to mean that even the tails into the CU should be dead if working with the CU cover off. Either it's a sign of the ever more safety-Nazi times we live in, or it's a sign of a poor standard of education and training. I'd love to see the expressions on the face of some of them if they'd been around when my brother and I were rewiring a house years ago. He's an odd individual with very dry (and I suspect thick) skin, so he barely feels mains. When we were functional testing the lights, his party trick was to poke a finger in the lamp holders whilst I flicked the switches. He could just about feel mains voltage, no jolt or other reaction.

We built a 130m² house, with me doing the plumbing, heating, ventilation, kitchen and bathroom fitting, flooring, joinery and decorating myself for £1380/m², but that cost included solid oak joinery. We could probably have come in at around £1300/m² with a bit of cost-cutting. £1300/m² would work out at about £350k for a 270m² house, excluding the cost of the plot.

There is a host of info here about build costs in other threads, and it very much depends on where you are and how much work you can put in yourself. At the lowest end, then Northern Ireland seems to be the least costly place to self-build (based on members here and their experiences). Doing pretty much all the work yourself you might be able to build for less than £800/m² if you lived there, perhaps a fair bit lower if you know what you're doing and where to buy stuff. If you're in England, and can only do stuff like plumbing, kitchen and bathroom fitting, decorating, heating system installation etc yourself (pretty much what I did) then the costs are more likely to be around £1300 to £1400/m². At £1300/m² then you'd be looking at a total (excluding land) for a 270m² house of about £350k. Some here have managed to get the costs down closer to £1000/m² with a lot of DIY work, but that's still going to be around £270k for a 270m² house.

As well as being a bit rough, the chances are that a garage floor will have a slope. It's quite common for garage floors to be built with a slight slope out towards the door.

The bottom line here is for anyone seeking advice to sift out all the stuff from those that have little or no practical experience from those that do. If I were after advice on ICF, then I'd first of all take heed of those here that have built using an ICF system, as their views are massively more valuable than anyone who has not built using ICF. With regard to bracing, then my view would be to take heed of the experience relayed here by those who have first hand experience of failing to brace walls. What a manufacturer publishes on their website means diddly squat if the reality is that winds or pouring loads can dislodge an unbraced structure. Reading this thread there are opinions expressed by several people who have first hand experience of building with ICF, and their comments are worth 100 times more than those of someone like me that has never used the stuff. In particular I would take heed of @jamiehamy, @AnonymousBosch, @Russell griffiths, @Triassic and @Alexphd1, as they seem to be the only members posting in this thread that actually have experience with ICF. Some of the other comments may well come from just using a search engine.

Sadly this is not untypical of the sort of really awful work that gets done when there is grant funding available. Many local authorities have dispensed with their Clerk of Works in the cuts, so contractors know full well that there isn't likely to be anyone judging their workmanship. First step is to send those photo's to the person in the Local Authority who is authorising the work, and at the same time requesting a stop on all further work until such time as the existing work has been independently inspected. If that fails to produce a satisfactory outcome then I'd take the images and story to the local media, as they will relish publishing it, I'm sure, and there is a fair chance that it might get picked up by national media. Either way I'm certain that the local authority would be forced to act quickly.

I agree, but it's been completely normal practice for as long as I can remember to vary the catalyst ratio to compensate for temperature variations. IIRC, the minimum is around 1%, the maximum around 3%, with a decision being made on the ratio to use based on the temperature and the volume of the mix (higher pot volume = higher initial temperature rise = lower catalyst ratio needed). As long as there's enough catalyst to start cross linking before the styrene evaporates then that's generally OK. I well remember laying up the deck of a fairly large (~40ft) boat indoors in winter and deciding to erect a plastic sheet tent over it to try and reduce the risk of the styrene evaporating before the cure was well-established, as being such a large single lay-up we'd used a low catalyst ratio to extend the pot life.

Slate is best for floor packers, as it doesn't compress with time. A bit more fiddly to get the levels spot on, but it's what I'd use.

I agree, a 760mm door is going to be a bit on the tight side. I made the side door on my workshop the same width as all the doors in the house, and they are all 838mm. To answer the question, I've just checked and our internal door linings are all 30mm thick, so allowing for two of those, plus a working clearance for the door, plus enough width to pack the lining true, I'd say that the rough gap needs to be around 70 to 75mm wider than whatever size door you go for. You can get slimmer linings though. I believe some may be around 25mm to 28mm thick, which might knock a few mm off the rough gap needed.

There's no substitute for a bit of GRP experience when doing a roofing job, as it's probably one of the most potentially difficult GRP jobs to do, just because of the extreme sensitivity of polyester resin to slight changes in temperature. I've seen experienced GRP boatbuilders struggle when doing roofing, because of the need to fine tune the amount of catalyst to add. What's worse, is that you can run the risk of under-catalysing the resin and have the styrene evaporate off before the resin has cured, leaving a sticky mess. I've done a couple of roofs with GRP and found that the secret is to mix the resin very quickly and quickly empty the whole mixing pot on to the roof, then roll it out. If the resin sits in the pot it will warm up and start to cure too quickly, and spreading it out slows this down a lot, giving more working time. This only works well if the roof isn't hot, though. Not a good idea to try and do a roof in bright sunshine. Equally not a good idea to try and do a roof if there is a trace of moisture anywhere, as moisture is a real enemy when it comes to GRP.

The blaming of Brexit for price rises reminds me of when we changed to decimal currency, when the same thing happened; many hiked their prices and blamed decimalisation.

One thing I learned early on was to ask anyone who you found to be good for recommendations for other trades. The good people always seem reluctant to recommend anyone they viewed as having lower standards than themselves, so this was a pretty good way of helping to select people who did a decent job. Our biggest problem by far was finding good people who were available when we needed them, and that was at a time when the building industry was a bit in the doldrums.

The temperature differential relationship with regard to cooling should be broadly similar to that for heating. Yes, more cooling power is needed than heating power for sure, as it's easy to get a few kW of solar gain, and for a house that only needs maybe 1kW of heat in winter the overheating effect from solar gain may well be significantly greater, hence the need for more cooling. However, we rarely need to heat the surface of the floor with our UFH above about 23° to 24°C in cold weather. Cooling the floor to around 18°C draws a fair bit more heat out of the house than we put in from heating during the winter. (~4°to 5°C temperature differential for cooling versus ~1° to 2°C temperature differential for heating) .

I costed up Isoquick, Kore and Supergrund and all came out within about 10% of each other, which was about £120 to £130/m² for the design and materials (SE fees for the structural design, foam insulation, steel reinforcement, concrete) without labour. This cost could be reduced by just buying sheet EPS and fabricating the corners etc, although you'd still need an SE to do the structural design. The longest jobs are levelling the blinding before laying the insulation and fitting and wiring up the reinforcement.

The films we used were Solargard and 3M, with the cheaper Solargard Sentinel Plus on the front glazing, where we wanted privacy as well (a neighbour decided to cut down a load of really tall leylandii). Although the Sentinel Plus was cheaper it's still an idea to be sitting down when you get the quote! The more expensive film is just as IR reflective, but barely has any tint to it, and we have that on the East facing bedroom windows. There are a few threads here covering it, and also an excellent one by @NSS regarding his Sage Glass (I wish we'd opted for this now, despite the apparently high cost). This is the thread for Sage Glass: https://forum.buildhub.org.uk/topic/2957-sageglass-live/ This thread has details of the films we used: https://forum.buildhub.org.uk/topic/6474-window-film-further-info/?tab=comments And this one has more useful info and pictures: https://forum.buildhub.org.uk/topic/308-window-films-for-uv-protection/?page=1 Sorry for the thread drift!

Ours were the same. They started off by saying they would only accept slate or hand made clay tiles. I fitted Ikoslate (recycled plastic made to look like slate) and they couldn't refuse as they weren't able to spot the difference between that and real slate. Anyway, their case was blown out of the water when I pointed out that the listed building opposite (which was being used to restrict what we could do) had a roof covered in old asbestos slate.