zoothorn

@PeterW or anyone.. i'm having trouble actually measuring the fluff. It seems to be 100mm between joists, but 130mm the layer ontop. is the stuff measured @ 100mm squashed in the pack, so it expands -more- when unrolled to say 130mm? I guess i just go 100mm of 3rd layer whichever it may be, in order to get to the 300mm figure.. which I think is min for B.regs? In which case I've been done over by about £150 min by builder, and it never had a chance of being up to min b.regs requirement at either 200mm, or 230mm as it seems to total, by my measurements.

So idea is it ideally goes just over lamp.... not transformer in too? Ive enough lead so xfmr can sit next to joist, but under fluff.

Would this be ok to go as my 2nd layer, @joe90 or @Onoff ? It is used at the joist level for cold roof applications (Looks same as other orange "Superglass" one, but @ 5.3m as opposed to 4.8m.. for £same.. I can complete my 2nd layer -just- with it). Its the spiel on it saying " It is used at the joist level for cold roof applications " & nothing more, not 'over joists too' like other one does. Same-same yes?

@Declan52 Declan re. my plant pots.. does the downlights' black 'junction box' fag pkt size whatnot have to go inside too? would this be a transformer, and not a junction box maybe? (in which case might this be the thing most likely to get hot.. or is it just the bulb/ lamp really the 'concern' here).

Its poorly fitted on the sloping side, yes there might be bits even missing.. just have to hope not. There will definitely be gaps here, but I cannot remedy this. But if the lower room door is considered, opening to outside, with gap under door, frame poorly stopping the cold too.. & this room's toasty even so.. then a bit of inadequacy/ gaps can still mean a toasty room. Have to see what this loft insulation redo does to the room. I guess proof's in the pud.. my thermometre's there ready.

@Declan52 spot-on advice as always.. that's very helpful/ I was wondering if a notch needed in me pots. I'll certainly try putting in what I can, now I'm reassured about squashing the fluff down/ not ruining my pB ceiling. I just have the nagging thing about the cables: whether they'll determine now how much extra fluff I can put in, if its paramount they lie ontop of it, I assume its only mostly so (some will innevitably have to pass thru & up, and some within the fluff too/ skirting along a joist or so).. it cannot all go ontop, even as I have it now call it 200mm. I'm gonna aim for 300, try for 350. Much appreciated- zH

Hi @ash_scotland88 thanks for casting your opinion/ reading my stupidly long thread! (Im a newbie/ amateur, hence takes me 6x to understand stuff, let alone 10x to build it). I've thought of your 'coldsink' idea (PeterW also has this opinion) but alas I have to correct you: in fact the lower room (directly below) -doesn't- have such a hallway. So it has the same wall (old end of house) as one of its 4 sides, just as the room above. In fact, both similar in area too. So the sort of mystery is, to me anyway, why if the lower room has a rad in half size of room above, & with all 4 walls similar, why is this lower room super toasty.. but room above totally different/ cold. Yes the lower room is 250mm lower; but has a rad half the size, and a big (obvious) weak point too: it has a cheap pine door opening to the outside, that's not even airtight (I go in/out of 20x a day too). Anyway I need to cross off the 'doables' 1st, the loft undoubtadly 1st, esp if I find a 4ft area of bare pB up there, where my spark didnt bother pulling the insulation back over (undid a pB section for access, to fit 4 downlights). The 2nd being the door yet to make for top room: this doorway, unlike room below, goes into the adjacent master bedroom (a knock-thru created in old end wall).. a blanket up temporarily here, which tantalisingly, has made a bit of difference (like 1*). Balancing rads 3rd, in case this huge rad isn't putting out what it should. Then if these 3 don't work.. I'm up a gum tree (& tbh I might have to call it a day, just always will be a cold'ish room.. like all other rooms are, bar the toasty workshop!). Lining the end wall is 4th.. but loathed to, 1) bc of space intrusion/ lessening, 2) the character gone, 3) the work/ mess/ logistics to do it (& 4) it might it not be the cold cause anyway, if lower rooms seems ok). The other side of

I did to the builder & to BCO both happy- & we did discuss this sloped area, after BCO telling me a figure he told builder to put in (I recall as I was surprised it was thick'ish PIR). But as to exact fig he said, I just went with it being a him + builder talk, not my having to note then AND 'check' as it was being built (not knowing it'd be impossible to access, even once a hatch put in). You do put a certain ammount of trust in your builder- altho I admit I knew he was stringing me along at this stage in other areas, so it could be he hasn't put in what he should. But even so, if 100mm in, as I know to be minimum, instead of 150mm, its not going to be the sole reason I can only ever get the room warmed to 17.9* max, however long the huge rad is on.

Ok thanks A_L. I'm not exactly sure where this info leaves me. It may be possible these two PIR pieces are in fact 75mm tho.. I cant get near enough to get a measure on (& looked to me like 50mm Ive use alot/ under caber floor etc). I'll try squeeze in but Im quite fat might get stuck. only the squirrel could rescue me then.

150mm?? PIR?? 200mm?!? So this is more than the 140mm PIR I was told to put in the timber frame inner wall. But that doesn't compute. I'm not sure if your point is telling me what the B.regs stipulate (I still cant glean any info from this table, bar '100mm thickness' so I'm also unsure where 150 & 200mm figs even come from), or if your suggesting what I now have to do is approach my builder to tell him he needs to come back/ add 50mm, or approach my BCO & ask him to tell builder to.. or, if you're implying I have to top up the 100mm I find, by min 50mm, somehow, in order to satisfy myself that the cold isn't coming in here. I haven't got a clue what these tables, and posts surrounding them, are for/ what points is being made relative to the thickness figures.

The BCO surely is coming back if he's got to sign it off. He hasn't even seen the pB & electrics job yet/ hasn't been in since the builder left exactly a year ago when he ticked his boxes off as it were/ so I could pay & be done with him. All I know is along this one sloped side, 100mm of PIR is in, albeit not very well afaict.. but I cant access it to change it.

Hi ProDave- understood. But if I only have so much 'loop'/ slack between the 4x downlights, if I put in 300mm worth of fluff, the cables have no choice but be -mostly- covered by it. I'll only be able to lie the 'top of the loop' on the surface. And if I go 350mm, then its all buried for sure. So what do I do?

No dpm, this is why I'm asking if anyone knows what this figure is! Im given a table, but there's nothing on there, a bible with pg 16 Im told to look at, but nothing on there either. Surely someone would just know. 100mm? 75mm? 125mm? Its likely to be one of these, 140mm of rigid is just too thick for any ceiling area, if I've been told to put 140mm in the walls. Anyway I can't be responsible for any shortcomings my builder might have built it to. If it should be 100mm, and BCO measures 75mm.. then builder has to come back. Same with general loft stuff I'm at least 8sqm short (if not another full 16sqm of 100mm too).. but as I need to crack on/ as I'm cold/ I can't wait for BCO.

Yup understood- my board does go a bit bendy in middle you see. Its gonna be a helluva struggle getting anything else in tho tbh even with board across joists. One other thing: the leccy cables: they do a loop up & over, in series etc. I've seen clips whereby its said to bring them up on top out the way.. but its innevitable some will be within the insulation, actually a fair bit, esp if I'm going super thick adding my 3rd layer/ much will be immersed.

I'm still stumped. I thought the point in Q was the rigid stuff in the sloped ceiling-? 100mm or thereabouts, I'm roughly sure. I'm not understanding any of the table stuff I'm afraid, but am I meant to?. But thanks for efforts to help.

@PeterW Ive used up all of builders fluff.. & I'm exactly 1/4 of the loft area of it short (if two layers of this is acceptable for B.Regs that is). That p*sses me off, but doesn't surprise me, goes with the other 'string him along he'll never know' xyz. If Id asked him to put a hatch in, as he asked, he'd have had to put in 270mm min as BCO would go up & look. As he'll do now. And Im 70mm short (I think) after this 2nd layer done. So I need another 8sqm of this orange to finish this 2nd layer, then a last layer. But I just dont see how its possible to put another layer on even 70mm. If I put a board on, it'll put too much pressure on the pb with these two layers surely.. so I just don't see how its feasable to cover anywhere other than at reach from the hatch. The only way is crawl along centre 100mm wide brace- but its so cramped at 4' at pitch, one foot wrong & disaster.

Not on my mellon patch you don't. Nice creatures. I did find a probable p*ss patch mind you (unless it was me/ I am doing very occasional 'expulsions' now Im middle aged esp whilst crouching). Just gotta block up his access point.

I cannot see anything there, there's not even a '100mm' figure, and I dont see any notes.. I see a blue area, but again nothing relating to insulation figures. Thanks, but its like a bible of info to me/ its for building control, not really customers afaict. If anyone knows what the rigid insulation is meant to be here, sloped ceiling bit? (& why it should be any different to a flat area). I do find another 50mm hidden under/ so I have 100mm here in fact. thanks tho- zoot schmoot.

What is the regs, & why is just a bit of ceioling that slopes, as opposed to it just being flat, mean anything different needed here anyway?

Hi dpm. There's a slope on only one side, here he was told to put in 50mm rigid. I can see he's done that.. but is not properly fixd in, loose/ awful old offcut scraps, & likely gaps/ but its too inaccessible for me to redo it. I can close the void above it though approx 200mm, with orange stuff, but it means closing the gap up to the white roof membrane. Tbh its all on hold until I know what to do about these 'skieling' areas: both sides they're 200mm voids, this slope side just going down an extra 2ft .

warmth? fk no. they're better off in their tree.

Yes & no. Yes I think they're not sh*tting up there, but no I don't think they won't be sh*tting somewhere else. They dart in, bury their nut, & f-off. Or come in, unbury their nut & munch it thenceforth, & f-off forthwith.

ProDave should be pushing this 1st layer between joists right up to/ meeting the roof white membrane? I think the word might be the skielings/ anyway the least accessible part of each joist row, where the roof is nearest, & where there seems to be a 200mm gap, I think area ontop of the walls is this bit?

Aha ok joe thanks. I thought you were designing your new wall.

Yes, but they visit rather than live with me like my mice. No droppings, no goings to- fro from main house loft to this. Hence i was really happy to find acorn bits. I thought it sounded too big for a mouse! So another job to patch up eaves gaps.. why they're even built big enough for a rat size mammal to enter is beyond me. It jus5 shouldnt be.