G and J

Thank you. That’s a well done for J. I did the polystyrene and the (*&#£*!!! ing) PIR in the floor. J does the walls.

Just looked back at our quotes from our local Jewsons. EPS70 was less than £47/m3 PIR (foil faced) was less than £87/m3 Both for 120mm thick 2.4m x 1.2m sheets held in stock locally at their suppliers.

Is that assuming a BnB floor with the underfloor void being the same temp as outside? One of the reasons I was pleased to go first a solid floor was that the ground under would be a more constant temperature possibly 7C.

If we could do a calculation to determine the total carbon footprint of option a - keep the gas boiler till it dies then replace with latest tech, presumably upgraded heat pump, vs option b - bin the gas boiler and replace immediately with today’s heat pump, I’d be shocked if option a cost the planet less due to the wasted resources out into the boiler. I’m dead keen on renewables. We even paid a daft amount to have gas removed from site. But it’s easy when it’s effectively a blank sheet. Sadly such an analysis would be so affected by multiple assumptions that it would be hard to believe in it. But gut feel says your wasting the planet and your own money replacing newish kit now. But who can really know?

Oh I like these new year confessions as it makes me feel less uniquely dumb. No less dumb, mind, but less alone in my folly. I think I’ve done the same damn stupid thing three times. Carefully put catching bowl under sink trap. Skilfully dismantled said trap with spilling a drop. Then thoughtlessly dumped the nasty water from the catching bowl into the above sink. Sigh.

Allow me, (in my post New Year’s Eve socialising, sleep deprived, just driven 3.5 hours and me adrenaline left the building about 5 miles short of home state), to translate into buildspeak. ”Dunno. Hard innit. Better put enough in to stop anyone moaning, which means too much. But sod it, it’s cheap enough.” :-/

Just for you. Frame insulation: Then VCL and more timber battens and an extra 60mm of mineral wool.:

Thank you. We start the new year with our chilly having a birthday at Christmas. With him and me on site the average site age has just risen to just over 70. You’ve heard of Jerry built. Well ours is geriatric built. lol

I’d strongly agreee, using a piece of wood knelt on as a guide for me really sped it up. Both polystyrene and PIR made mess, but for me only PIR was unpleasant.

We ended up with 335mm to 345mm to fill to get to FFL which includes screed with UFH. I am keen on a good thickness screed so wanted circa 100mm. So for us the insulation thickness was given. We want the biggest living space we can fit in to our narrow plot so our walls haven’t the most fantastic U values so to an extent the floor and ceiling can sort of compensate a bit, so I targeted 0.1 for the floor. Going from the architects suggested 0.13 U value to that felt ok, cost wise. Beyond that felt silly.

Because I’m not on site today I just calculated that had I gone for all PIR instead of 120mm each of polystyrene and PIR the payback (assuming underground temp of 8C, COP of 4, peak time electric cost, etc.) would be in the region of 117 years. Hmmmm. Perhaps a good illustration of the diminishing returns of insulation.

I’ve heard of ash felt floors being laid in old places which as well as being water resistant, apparently made the places warmer than they were (probably was bricks direct on damp earth or the like). It would be interesting to see how homes are built in 50 years time given the pace of change.

How long before some clever wotsit comes up with a self levelling compound, made in a lorry on site and pumped in, that also functions as a DPM. Until then we’re still talking sheets. I accepted a slightly higher wastage (~4%) as I didn’t want small bits and when I planned it out that required a couple of near half sheets spare. Some of that had been used elsewhere like the former for the shower tray to exclude the screed. Unusually for me, the sheets went down almost exactly to plan. I think the only change was to make the PIR layer slightly easier to get as tight a fit as I could.

In the excitement of moving soil from a heap to a hole I forgot. Sorry. Will try harder!

I think you need a certain number of air changes per hour to keep all fresh. With trickle vents it’s a blow through. But with MVHR one still (as I understand it) get a good flow through if fresh air. It at first appears confusing that we have a really low air change score to make MVHR worth having, but that’s a test of the leakiness of the house, not the number of air changes that a good ventilation system will give.