G and J

Is PIR that bad to work with?

If you did that for me I’d have to draw Everything, Everywhere, and all at once! :-0

I’ve been thinking about our loft, insulation and access. We will be storing v little or maybe even nothing up there, but there’s Solar and probably a hot water header tank which may require the occasional bit of maintenance. It occurred to me that I could use soft insulation between the chords of the fink trusses, then put a walkway down the middle made out of a sandwich of: 1. the cheapest material I can find (or salvage from the demolition); 2. some seconds quality PIR or EPS; 3. topped with again, cheap or reclaimed boarding. Then that’ll give me a sensible walkway, good insulation under that walkway, and I can put loads of soft insulation to the sides of the walkway and never need to compress it or fart around finding trusses to stand on whilst worrying about popping plasterboard ceilings. Could there be any mileage in something like that for you? Would one even need a walkway in the bottom or, given the rare use, just put the PIR straight on the trusses (which sounds sooooo scary!)

We’re talking to a timber frame kit supplier (who do not erect) who provide circa 8’ x8’ panels sheathed with 9mm OSB. So the architect is simply suggesting the fire resistant layer goes straight onto the OSB with the breather membrane over that. But I’m not keen on paying for Supalux!

Fab, ta. Will investigate

I need a recommendation for a fire resistant board for our upstairs walls. We are within a metre of our boundaries on both sides. We have a rendered blockwork skin on the ground floor, but not upstairs. Upstairs we are having fire retardant treated vertical wood cladding, so we need a fire resistant layer between the frame and the cladding. We are assuming this layer will go on battens on top of the breather membrane. I did look seriously at Magply, which it appears can be the frame sheathing too, but then discovered that warranty companies really don’t like magnesium based boards. Our architect has proposed 15mm Supalux, and whilst it’s rather whizzy it’s also eyewateringly expensive, so we need an alternative, kinda pronto. Help!

How long a run are you looking at between the ASHP and the house?

Great minds or two fools not differing? 😉

You bet it is. I can confirm that if one’s initial assumptions are of too narrow a wall thickness then many hours are spent boiling one’s brain and an enormous quantity of scrap paper is produced. At least we’ve now got a good supply of stuff to start fires with this autumn. 😕

👍

You could purchase an Ethernet cable on eBay of roughly the same length and see if that behaves the same. If it does it’s not your cable.

Only 90 odd. Crumbs. I'm sitting in a house with 20meg broadband tops, and everything works fine and dandy and quickly too. What benefit does one get from the extra speed or is this just future proofing for the invention of 32k TV (as standard)?

It also looks the part!

Ok just in case it's of interest......we met with our architects last week to finalise detail as we move into BRegs and Discharge of conditions. Long story, but we have added block skin to back render on ground floor and it's our preference that the upper storey cladding overhangs the ground floor render........question was "can we effectively extend the cladding into the airspace beyond our planning footprint" - we were talking 31mm on each elevation. Now caveat to our situation is that we are on a narrow site (1m from a "very intetested" neighbour), but our architects view (local, working relationship with LPA) was that pre covid, he may have seen one enforcement action a year, he currently has 8 on the go, with a number of those needing to go back into planning.......his advice was "do we want the added hassle?"

I think that’s exactly what we are facing. We’ve a 3m x 5m flat roof with a fair bit of that taken up with a skylight. I think the difference between internal ceiling height and the top of the parapet that surrounds the flat roof is between 450mm and 500mm. Posi joists will be 254mm, plus we need to be able to walk on the flat roof for maintenance/window cleaning. Reading this thread it sounds like we’ve no choice but to have a cold roof, but how on earth do you ventilate it?

Snap. Only I’m too tight to buy PHPP so I used Jeremy’s spreadsheet.

We are planning to have rendered blockwork on the ground floor with vertical wood cladding upstairs (assuming we get our non material amendment approved). The step issue was the same for us so are planning to step out the upstairs frame in places rather than build in voids. @CaptainRatty Could you do that or is it too late?

Would I be correct in inferring that the main benefit from a pressurised system comes from the quality of the tank? If so I could use a pressurised tank but on gravity. 🙂

Good plan. I assumed I would have to screw the frame straight to the timber. Ta for that.

Like this you mean?

My understanding is that they aren’t big enough, they’re only about 2’ either side, hence steel being unavoidable. If the goalposts are in the corners, then methinks, I can thicken up the timber frame between the post and the patio door and reduce the effect of the cold bridging?

On the back of our house we will have a 3m single storey bit with a flat roof. The rear face of this comprises a 4.1m set of patio doors flanked by two little stubs of wall. We've been advised that we need some ‘goalpost’ style steel to provide racking strength, which I can easily understand. What I can’t work out is if it is better for this steel to be tight to the patio doors, or is it better to have it full width, i.e. into the corners. I can imagine that option 2 is better from a cold bridging point of view but I can also imagine that I’m missing some other fundamental factors. Comments appreciated.

Crumbs, the things I don’t know! Thank you.

Is it ok to use beam and block outside? I thought the metal reinforcement in the beams might blow?

Cash is not profit.