UFH

Gas!

For some, the choice of a passiv-standard house and a gas boiler for hot water and UFH provision  would appear to be an odd one. Why not fit a ground or air-source heat pump (GSHP/ASHP)? Well, a number of reasons actually. GSHP aren’t cheap (could easily be £15k+ by the time it’s finished) and they require a fair bit of land into which the pipes are buried. Although our garden is a reasonable size, not all of it would be suitable for laying the pipework. ASHP aren’t particularly efficient and still quite expensive, although they are a chunk cheaper than GSHP. Gas on the other hand is pretty cheap to install and run – and we have a gas main running right across the front of the plot. On top of that our heating demand will be extremely low so paying out more than a couple of thousand for hot water just doesn’t stack up. Being efficient is far more important to us than fitting ‘stuff’.

I’d been warned many times that getting the utilities organised and connected was probably the hardest, or least most frustrating, part of the build. Not wanting to be caught out, I made initial contact with each supplier very early on in the process – I knew the gas connection wasn’t a priority but I still wanted to be on top of it all so I made the initial call to get it kicked off even before we’d broken ground.

That call amounted to Good News – the connection was relatively cheap (£400-ish); we had the option of digging the trench on our land for the pipe ourselves or letting them do it; and they only needed 4 weeks from start to finish. Easy! So I parked it.

Fast forward to the end of March and talk of needing to get the UFH up and running started. Obviously, we wanted to get it working in case there were issues that would need resolving but we also needed to get the floor fully dried and the system ‘run in’ before we laid the wood flooring and tiled the utility room floor. No problem, I’ll just get the connection sorted – it’ll be about 4 weeks.

One phone call later and 4 weeks became a stated 6-8 weeks! Major panic ensued, in me at least. I got the groundworks guys to dig the trench at the side of the house and National Grid came out to survey the site. All good except they weren’t happy with the duct I’d had installed in the wall of the plant room through which the gas pipe would route and instead they insisted that they drilled the hole themselves. Not in my house you’re not – you’ll use the duct! We had a discussion and everyone agreed that I was getting my way, which was nice 🙂

While the trench was open we had the BT duct, water pipe and a duct carrying the mains electric to the house laid at the appropriate spacing and depths. National Grid actually laid the gas pipe at the end of April – almost 4 weeks to the day after my initial order! Naturally I then proceeded to forget that I needed a gas meter. School boy error.

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Yellow is gas, blue is water, grey is BT

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Grey BT duct laid and pegged by ourselves. Gas by National Grid. Water and electric below

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Gas and others enter the plant room

You’re generally given a few options by National Grid as to where the meter is to be located. I think these days they like to fit them in a cabinet set into the external wall. Now, not only do they look ugly but in a highly insulated and air-tight house they are a Very Bad Idea. Another option is to have one installed externally at about ground level. I don’t like these either but if that’s what we have to have then so be it. In fact we didn’t need either of those two options and were able to put it inside the plant room right by the boiler, exactly where I’d planned for it almost a year earlier!

Meter installed (despite a load of par-for-the-course whinging by the installer) and we were up and running. Boiler fired up, UFH running, no leaks. We were in business. Of course, we were now into June and the weather was warming up. Good insulation, an air-tight structure, large amounts of glazing, high external temperatures and a UFH system that was being slowly ramped up to maximum isn’t a good mix. It was HOT inside the house. Really hot. Too hot to work comfortably, that’s for sure. No surprise then that the electricians switched it off a couple of times! One saving grace is that we’ve built on top of a hill (the slab is 79.00m above sea level) and with the windows and doors open we get a lovely breeze through the house, which did help to cool things down somewhat. It was still warm though.

 

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Gas meter installed

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Neat plumbing

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Plant room getting busier

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UFH pipes – thermostat heads ready to go on

Anyway, it’s off now. The next job is to try and work out which pipe belongs to which room/loop so we can fit the thermostats. I ‘think’ I know which is which but I’m sure we’ll find out sooner or later.

MVHR

Just one last job before I forget. The plant room was looking pretty untidy as I hadn’t bothered to connect the red MVHR ducts to the distribution boxes. I decided it was time to fix that. I’ve got a couple that I’d like to tidy a bit better, but it’s looking pretty neat now I think.

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Passive slab is going (still)

Well, by now I was expecting to be able to say the slab was finished and the timber frame was just starting to go up. No prizes for guessing that’s not what’s happened. Progress wasn’t too bad although the team on site didn’t get the extra manpower they thought they were getting, so it wasn’t as quick as it might have been. No complaints with the guys here though – they’ve really put in the hours.

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EPS perimeter down

Over the course of the first 6 or 7 days the blinding material went down, ducts positioned for services, the EPS (Expanded Polystyrene insulation) perimeter was set out and then more EPS was laid to fill it all in. In total there is 300mm of insulation, rising up to 450mm at the perimeter. Following that, the rebar (steel  mesh) was laid and then the underfloor heating pipes on top of that. All ready for the concrete to be poured!

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Rebar going down

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Trying out the non-structural blockwork founds

So why, 14 days after starting are we still waiting for it to be poured?

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UFH in progress

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UFH detail

Who’s the novice?

For quite some time I’ve been chasing up all the various parties to ensure that whatever information was needed by Building Control had been sent to them. For whatever reason, not all the information relating to the slab and timber frame had been prepared nor sent to BC. I won’t point a finger of blame. But I will say that it wasn’t my fault. You know what they say about leading a horse to water? Ah yes, water – we still haven’t got that yet either. That’ll be another blog entry I think.

Anyway it’s all sorted now. It did take a bit longer than hoped for but that was really due to the BC’s structural engineer never having seen a construction like this before so there were a LOT of questions/answers. In some respects I’m quite happy with this. I’ve never doubted the timber frame design nor the engineering calculations, but having a completely independent professional agree with it all just gives that added level of comfort that it’s all good.

Actually, it’s not quite all sorted as there is still one question outstanding relating to the windows. This won’t stop us pour the concrete but it does need to be resolved before the frame goes up. Again, it’s nothing I’m bothered about but I think the window supplier has to get the responses from the manufacturer in Austria and they’re not the quickest at responding. The window supplier has been quick to come back with as much as they can for everything else though, so no complaints there.

BCO (Building Control Officer) is now due to inspect the site in a couple of days and assuming no issues are highlighted during the visit the concrete will be poured pretty much straight after. I’m quite looking forward to that 🙂

Ready for the frame, then?

The concrete needs to set for a week to 10 days and the frame can go up. However, two things have made me delay the frame erection by 3 weeks or so, which might seem a bit mad at this time of the year but there is (some) logic in the decision. The first thing was the delay with the slab, although not a reason in itself. The second more significant part of the equation was that I found out that the windows aren’t due to arrive until some time between the last week in November and first week in December. I’d rather not have the frame exposed to the autumn/winter elements without windows for any longer than necessary so pushing out the frame erection helps with this without actually impacting on the end date. No brainer.

That’s all for now, but hopefully there will be another update in the next few days.

Utility update

Nearly forgot… tomorrow we get a visit to connect the water. Well, I am 99.99999% certain they won’t actually connect it but we’ll get a visit all the same. I’m more interested to hear what the excuse is for not connecting it really – it’s quite amusing in some odd way to witness pure incompetence at ‘work’.

I mentioned in my last blog entry that the electric meter didn’t get connected. It turns out that they didn’t come as the address wasn’t registered on their system. Except it was – even they told me it was. So, complaint duly raised and new date scheduled for a week on Wednesday. I could do with putting a roof and doors on that enclosure now.