Stones

The site only had 200mm cover of topsoil, and in digging into the hillside we were well into the hard so no need to go any deeper. Standard 150 x 600mm concrete strips, which despite the deceptive photos, are 450mm below finished ground level. The next pour as I understand it will be to wall plate, so 6 blocks high. I'll know more when the actually do it, but there are a stack of adjustable braces sitting on site ready for that stage. I think the key thing is getting the foundation courses in so there is a solid and fixed base from which to build the main blocks off. The bracing will be fixed prior to the pour, then adjusted to straighten out and kinks in the block work. I suspect that avoiding blowouts is more about taking time and not rushing, than inherent problems with ICF per se. The biggest difference compared to what I have seen on the likes of grand designs, is that without a pumped boom concrete wagon, the process is a lot slower, and doesn't appear to put the blocks under as much stress. I'll know in a couple of weeks!

Hi and welcome.

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NEW ENTRY 4 weeks after we hoped to have it, our warrant was finally approved. Another weeks delay waiting for the digger driver, but finally work has started in earnest on site. Strip foundations were dug and concrete poured the following day. A minor set-back during the pour, a hydraulic line split on the mixer forcing it to shut down. An hour later after the mechanic had brought out and fitted a new line, the job was finished. You’ll note the lack of a digger on the concrete pour. 4 men - 2 on barrows,1 spreading in the trench, 1 tamping and levelling the concrete off. It’s the fastest I’ve seen strip foundations poured. Having finished the pour, the concrete was floated to a smooth finish. Not normally required with block foundations but as we are building with ICF, it’s important in ensuring that the base blocks are level. The ICF (Amvic) system blocks that we are using are formed from two sections of 65mm EPS separated by 150mm plastic webs to form a hollow core for the concrete. The plastic webs are embedded in the EPS for rigidity. Here is a close up of the block: Note the teeth on the top and bottom edges of the EPS, these ensure the blocks securely interlock with each other. The markings on the side of the blocks are to aid cutting and are set at 20mm intervals. So, after measuring and setting out, the first course of ICF blocks were laid. These were half blocks, a full block having been cut in two with a table saw so that there was a flat edge to sit on the concrete strips. A second full course followed, taking us up to just above finished floor level. The pour to fill the hollow core of the blocks took 1 hour. C35 concrete had waterproofer and steel fibres for strengthening added to the mixer. You can see the steel fibres here: A hoistable skip was filled by the concrete mixer and lifted by crane. Again, a team of four worked their way round the foundation, releasing concrete from the skip into a ‘funnel’ which ran on metal rails fitted over the top of the ICF blocks. The rails allowed them to quickly slide the funnel along the ICF block wall, filling up the core as they went. 2 men worked the skip and funnel, while a third, following immediately behind, used a vibrating poker in the core to agitate the mix and encourage settlement. Every segment of the block (as separated by the plastic webs) had the poker treatment. My builder followed round, running a line the length of each wall, bracing it where required to ensure the finished wall was straight and true. The finishing touch was floating the surface of the concrete in the core to a smooth finish, to aid the painting on of a radon barrier. Next entry - Upfill, insulation UFH and slab

Had a response from Sunamp about the 4 cell. It's not going to be available until later in the year, as they have the internal hydraulics to sort out and are currently focused on rolling out larger heat batteries. A side by side arrangement of cells seems to be the most likely which would mean a washing machine sized unit (a stacked 2 cell on 2 cell doesn't seem to be viable unless they introduce a racking system). I asked about treatment in SAP, and they advised they had had discussions about the various options, but currently don't have SAP points for any of their products. I've emailed them back and will be following up by phone again tomorrow, trying to pin down a date (as I have to make a decision sooner rather than later ready for first fix) and price of a 4 cell.

So provided I'm above the height limit, I could use these slim profile LED's that I originally linked to (be they the recessed or flush mounted type) without issue?

The other issue (for the bathrooms) is IP rating. Looking again at the zones and ratings, and as I will have a ceiling height of 2.4 metres (so outside zones 0, 1 and 2), it doesn't look like I'll need anything special in terms of IP ratings for the main bathroom ceilings. That would certainly simplify things and let me use the recessed LEDs previously linked to. If my understanding is incorrect, please somebody correct me! I can't help but feel that an IP65 rating over the shower cubicle would be a good idea given the likelihood of splashing etc.

I used an IP65 spot over the shower in my last house and it did the job in that enclosed space. Not sure they would be the answer for the whole room. I think it's time to order up a sample and take it from there. Question is, warm white or day (cold) light?

It's a very good point you make about PV (and one that TBH I hadn't even considered as PV is very much a post build project). A good analogy is the house we currently rent. It has a 5kW turbine and with a bit of thought could have a heating system tailored to maximise use of wind generation. Instead it has a number of power hungry storage heaters which all switch on and off at the same time. Running a lower but constant load, a fan heater for example) would keep the house warm but a virtually zero cost, whereas as it stands, for several hours a day, our import massively exceeds generation. On the oil boiler (or indeed gas boiler) front, I'm guessing such short bursts don't represent any problem, but the collective wisdom does seem to suggest that it is best avoided with a heat pump compressor. So other than being cheaper, a fixed speed heat pump has little going for it?

The appearance of a fixed speed ASHP on a well know auction site has got me thinking about this. The general thrust of opinion on the closed forum was that an inverter controlled heat pump is far better than a fixed speed for a number of reasons, but primarily; Soft start so kinder to the grid and matches its output to actual requirement rather than short bursts on full power (short cycling) A large buffer tank could of course be fitted to increase system volume and thus reduce short cycling of a fixed speed unit, but I think such a system would need to be very carefully designed to ensure the heat pump and buffer was sized such that it could run for a decent length of time. Noise and being prone to icing up are the two other concerns I have in respect of a fixed speed heat pump. I do wonder if we are overthinking the subject. An oil boiler for example (AFAIK) is either on or off and therefore when teamed with UFH needs a buffer tank / thermal store to avoid short cycling. It's not a massive issue for oil, so should it really be for an ASHP? True, an ASHP cannot deliver the high temps an oil boiler can, but even so, is running a heat pump at full power for 20 - 30 minutes every 2 hours really that bad? Thoughts?

Have a look here: https://www.systemair.com/en-GB/UK/Products/Product-selector/Fans1/ quite a useful calculator that lets you vary input values (water temp, flow rate etc) to determine the size of duct heater / cooler you would need if going down the MVHR route. I used it to establish how much a duct heater / cooler could deliver at normal MVHR air flow rates and on boost.

Is the coping aluminium? We are having something similar (know locally as Skews) but done in lead.

That's the biggest issue for me as well, although having to fit a fairly large buffer tank would be a pain I would rather avoid. I've only ever heard ASHPs working under part load, and they have all been whisper quiet. The other concern is how prone are fixed speed units to icing up, compared to an inverter which will just be ticking over and under little stress. I know from the EAHP I had in my last house (small fixed speed compressor) that it iced up after 45 minutes and required 15 minutes defrosting.

If you look closely, there appears to be a cut in the truss below the nail plate. I'm guessing the length of 6 X 2 was bolted on to compensate. Nick?

Just spoken to the vendor. These are FIXED speed units rather than inverter controlled. Control unit is integral to the heat pump itself. They are a good price, but I'm struggling to find a way of justifying the installation of a fixed speed unit. To make it work, I think a reasonable sized buffer would be required. Taking my house as an example, my heat loss calcs show that I'll need 1.3 kWh heat input at 0C ambient. A 200 litre buffer, assuming a target buffer tank temperature of 35C, and a delta T of 10C, would require 2.2kWh of heat input from the heat pump. Roughly speaking that would see it running for 20 - 25 minutes then off for an hour then back on. Not ideal compared to an inverter controlled heat pump.

So, a fire rated spotlight casing for those locations where I do have insulation present, and IP65 over the shower enclosures would do it?

So nothing to worry about - I did wonder about a chicken wire 'dome' over each fitting just to keep everything clear of the fitting (50mm or so).

Originally published on the old forum April 2016. Had to happen, the lack of a building warrant has pushed our start date back. I had started the process back in November and having been encouraged to do so, handed over the submission of the warrant application to a local surveyor well versed in our chosen method of construction. Without boring you all regarding the reasons why, the application wasn't actually submitted until the end of January and there have been delays in getting BC queries answered. We are almost there now, with the final list of queries being minor and with luck everything should be in tomorrow and will have our warrant by the end of the week. We have however done what we can on site, bringing in an access road, creating a hard standing working area for the contractors / crane / concrete wagons, and dug down to the level the house will be built on. We do thankfully have good solid ground (being a free draining shaley type clay and rotten rock) to build off so need nothing more than a standard concrete strip foundations. I do now have a mountain of the aforementioned shaley clay (which you can see in the background of the last picture) to use on site as the topsoil coverage was only around 200mm or so. We are planning to build up a terrace at the front of the house along with some general landscaping which should use up most if not all of what we have. Meantime I've been busy picking off pieces of rock/stone from the surface of the heap of spoil, larger pieces for landscaping / in the garden and smaller stuff to use in rubble / french drains.

If anyone is looking at cheaper supply options for Alu soffits and gutters, try MSP Scotland. http://www.mspcladding.co.uk/contacts.html I'm getting my alu cills from them for about half the price the window supplier wanted (fabricated and painted). They recently gave me a price for bespoke alu gutters, but will quote for fascias, soffits, coping etc. If it can be folded they will do it. Ballpark prices seem good as well, at £5 per linear metre for 2mm aluminium, 225mm wide (flat or folded), then a similar amount to paint in any RAL colour, although paint costs come down the bigger the quantity. I spoke to Derek in sales and he was certainly very helpful. I've emailed him to say he may get a few enquiries from forum users so be sure to mention buildhub.

What about proximity to rockwool type insulation - do they still require ventilation space (albeit limited) around the back of the fitting?

They are working on offering a direct electric charging facility as per the sunampPV, to the sunamp stack. This year sometime apparently. As is often the case with new products, it was developed with a particular purpose in mind but they have since realised the other ways in which it can be used and are refining their product line accordingly.

I've been trying to pin down what to do in terms of LED lighting, and frankly, find the whole thing a bit of a minefield. We have 3 requirements: We want downlights in the kitchen and utility. These will be fitted into an empty ceiling void (no insulation present). The hall is the second area where it would be nice to have downlights. However, this would mean having to develop a solution in terms of air tightness and contact with rockwool type insulation. Finally we have the bathrooms, with the same issues as the hall plus the need for IP rating (at least over the shower). TBH I'm really at a loss to know which way to go - 12V vs 240V, downlights or surface mounted. Looking on the old forum there were links and some testing of these; http://www.ebay.co.uk/itm/6W-9W-12W-16W-18W-LED-Recessed-Ceiling-Lamp-Bulb-Panel-Light-Fixture-Kit-Bright-/161449903807?pt=UK_HomeGarden_Lighting_Lamps_Lighting_SM&var=&hash=item25972a06bf As far as I can tell, they would cover the kitchen and utility. The problem I'm having is knowing if I can use these where I have the air tightness / insulation issue, and whether I could use for general lighting in the bathroom (accepting i would need an IP65 over the shower enclosures). Any suggestions warmly welcomed.

I looked into fitting a duct heater / cooler into my MVHR, to be run as an independent circuit from my ASHP. Certainly doable, but the biggest restriction on capability is the low flow rates of MVHR which means a rather large duct heater / cooler would be required. In the end, I've decided to make provision to retrofit, but see how the house actually performs in reality. An A2A heat pump purely for cooling (or instant boost heating) is an option for us, but only I think because we have a large open plan living space with vaulted ceiling.

Indeed, and very much highlights the problem with renewable energy. Orkney generates over 100% equivalent of its consumption (and that doesn't include what's generated by the 100's of <50 kW turbines dotted about the place. Overall, Orkney is 60% renewable, the rest either imported via a restricted interconnect with the Scottish mainland, or by an small oil fired power station in Kirkwall. Where we are building there is very little renewable (be it solar or wind), but overall in Orkney there is. My comments were more directed to the notion that as a 'green' requirement, there isn't really a lot of point as Orkney is already way over 100% equivalent in terms of renewable generation. The decision for me is purely a cost based one.

+1 on the tidy up as a first step. Fill the car and go to the tip (you can always invest in a sheet of thick polythene to line the car boot / seat folded down area, to keep the car clean. You might then want to consider paying your boys to do some of the donkey work - get them a set of gloves and have them pick out the rubble / bricks etc into a pile. Once you have a clear site, you'll be in a much better position to see the potential. You mentioned gabions as a possible retaining solution. Sleepers are another DIY friendly option to think about.