zoothorn

I don't like the sound of that.. sounds like a 'procedure'.

Aha ok.. didn't know masonry paint was't a form of emulsion/ another thing learnt then. I was sure there was some sort of primer/ adhesivey thing needed even before the 1st 5:1 first coat. No?

Well no spiel specifically worded 'new render'.. but does say ok on conrcrete & brick.. & I mean render is a plaster, & isn't it just white emulsion thinned down a bit which is simply what masonry paint is-?

Hi Actually Peter Ive just dug out some no-nonsense 'Bare Plaster' undercoat white paint.. would this be suitable? [sorry what does "MIs" mean]. thanks zoot

Just fitted a new bathroom 2 yrs ago, & put in a new backdoor!

Hi again chaps- hope this'll be a quickie. How to best apply a base/ primer coat on new render? drying 3 months now.. so can start thinking on this job. I've decent dulux masonry paint (white wales cottage) ready for main coat but £dear so ideally not use this 50/50 or whatever a primer coat might be. Thanks- zoothorn rollo.

Its ok for me, I think, as the whole shebang's been done via govt grant.. fingers x'd. But does what you say apply if my existing HWT is 'leccy?

I am an idiot & I'd like to ask a Q too. Does the outside box thing link up to the existing HW tank, if a new C.heating ASHP system is to be installed? Or would it come with a new one, specific to the ASHP system, included in the mix? IE throw old one in the river..? Thx zoot.

@Onoff My bathroom is appaling for this (walls so cold) & my backdoor worst: here I have so much black mould all around periphery the plaster's rotting. Anyway my only weak point is my french door sill.. can you advise on my door sill? Another Q. Any reason I can't put polystyrene offcuts as "fill" between my pozi joists? (got two useful 1m x100mm packing 'batons'). I mean only in a ~1m section. My rockwool won't quite reach you see.. so I'll have a 1.2m vacant section I can fill up with this + some 25mm PIR chopped up to make 75mm. So my joist will be filled tmrw with 140mm rockwool, with a 1m gap left (under doorway, directly above I think best) here filled up with PIR & polystyrene all wedged & foamed in. Prolly fill up over half the joist gap minimum, about as much as the rockwool will.

@PeterW thanks chaps- I had no idea at all about this, sure am learning as I go along. Ok good more reassurance on the condensation. Could either of you advise on my french doors sill: I asked builder to push the doors up 50mm. Why? bc A) he produced such a low set my head was almost hitting the frame.. yet another thing very not as per plan. And B) to scrimp every 50mm of height for my balcony [bc of his build height cockup] so doors will skim the deck). So its made it in cheap timber @ 50mm H. 240mm D isn't a good step for my size 11's.. so thinking I add a bit inwards/ easy. Tried to take up the OSB surface to whack in some PIR, but screws too hard. Its what to put on this timber sill is my Q. Or is it fine as it is?

@andyscotland ok that's reassuring.. but there's no way anything inside (including the render fully dried after 3+ months now) has any moisture content that's causing the condensation/ everything is bone dry. Today there wasn't as much (not as cold last night) so only the french doors had the condensation in the corners not the window reveal: evidently to me its due to cold outside getting in at the weakest point, the sides of french doors. If I line the door reveals (& top) with 30mm insulated pB.. which I will buy monday, 1 sheet will do the doorway/ window reveal below/ & the window area of this pesky too-narrow window upstairs.. I assume I'll stop this cold ingress/ condensation here. But this leaves the doorway sill. I don't think this PIR pB stuff is correct to line the sill, as full weight is stepped on here & pB isn't the right stuff anyway.. so what am I meant to do here? or is it a Q of just having one weak spot/ junction, & at least I've 'done/ lined' as much as I can.

Surely if I were to now put on a huge placcy sheet over the whole silver inside surface (a job to much for me/ I cannot deal with the prospect of doing this) this condensation will be trapped under the surface/ between these two layers, on top of the timber. I am just not understanding this situation/ what to do/ how its meant to be at all.

@andyscotland thanks for that info/ post Andy. Understand a bit more about 'cold bridging' now. I have it in abundance in my house as is. Ok so I will try & get my cut-down halves of 25mm PIR to line this upper window then after all. I'm still doing this damn foil job.. but I've been scuppered to progress/ do my french door reveal areas, by finding alot of condensation on the -inside- of both the glass -and- mostly at the very corners where I've put some foil (to be continued to complete the job). So the inside areas are soaking wet, water streaming down the foil tape.. & I can't complete the job as more tape won't stick on it. I'm finding this condensation situation infuriating. Not only I can't see out the doors as its satuated on the outside.. but now I find it in abundence on the inside too. I've no idea if this is a structural fault, something to be expected/ me to solve/ something I've introduced. What it seems is the silver metal foil tape's cold surface has introduced this condensation.

didn't think of that- dammit.

Yes my intermediate floor. I don't know why, I just assumed like the PIR behind the pB it needs to be close to it, rather than pushed back with a void behind the pB. Or, wouldn't cold get in the void from the sides.. where there's only a bit of timber between here & the wall cavity-? I still have a hunch the top room will be cold, because of the huge no. of timber studs used, the relatively average-at-best ceiling insulation (builder put in minimum required & ceiling not sealed), the big stone wall forming one of the 4 walls, the big glass areas on two walls (french doors, big window).. & the floor not being a nice warm 200mm celotex + screed, but instead 22mm of chipboard > 60mm void > & some fancy bum fluff.

Hi Andy.. but I need to try & keep it as high as possible (in my case up to the cables, that run under the top 'tier' wood top of the joist).. in order for there not to be a big void immediately below the floor, surely? If I staple netting over the whole thing I can only do this logistically on the underside of the lower wood 'tier' of the pozi-joist.. meaning a 60mm void. Surely this void = cold just below the floor. I just don't get the idea of this insulation job, especially having to negotiate around all the cables & not touch them. I mean how on earth ProDave did his, I have no idea. I can see the results, but how he did it.. & where the cables are is a mystery.

Had to make a choice.. went for only thing available (without a wait.. need to get cracking now) & that's 600mm wide rockwool. So Ive got to cut the damn stuff in half, then got bamboo canes to support it all. Not happy, esp Jewson wherby I cannot see the damn price online > go in, & have to take their word for it that the price is what they say it is (which seems dearer than I was quoted before). But I have no way of knowing or checking the price. So I think Ive made a wrong decision, if its gonna slump down between the canes fk it.. but its bought now. Is there any extra way I can keep this wretched stuff up? What is this ridiculous system wherby prices are 'hidden' from me the customer?? fkn absurd & drives me fkn mad.

Its the rockwool stuff, but its 400mm wide so I don't know whether it'll go in, bend in.. and its godawful stuff too. If I break 50mm off each bit the job will be an unpleasant nightmare. 100mm excess width.. is alot extra/ & its pretty solid slabby stuff.

But trouble is I have 3x builders merchants here, none sell the stuff.. I can't buy it online (without £45 delivery) so it rules this stuff out. Ok back to square 1. I have 300mm wide gaps between joists. What else can I put in here?

@andyscotland terrific thanks for that. I was concerned pre-cut meant me doing it.. I've only a handsaw/ could only see a zoot fluff nightmare ! Right good. So I'll buy (140mm) 380mm x 3. Two of. And fill the remaining 1.5m (two of won't quite be enough) with PIR offcuts. Plan sorted. Really helpful Andy- thanks.

Pre-cut 3x 380mm. So you mean I can buy 380mm stuff.. or is your suggestion me to cut it from a 1200mm roll? Its I think due to the fact that I have unusually small gaps, is why the problem here. Why this is built like so.. I have no idea. Seems too many joists to me.

Hi Andy.. thickness, do you mean their Height, or Width? If my gaps are 300mm wide, I just need to establish what width of stuff to buy. If 300mm.. it'll fall out. If 500mm.. it'll perhaps likely no be able to go in. If its very dense.. then 400mm might still not be able to squash in. I don't know. I may have asked this a few weeks ago, but I just can't find where.

You see the thing was, my builder used so much timber 'packers' (horizontal layers top & btm of room) Ive got alot more studs going on than I should. Seemingly around the window/ door too.. alot of timber going on.

Ok great I'm gonna call the vapour box TICKed. Andy do I even need to PIR line the reveals, at the sides?? could I just do top/ btm with a full 25mm PIR, pB on top.. sill on lower (I have enough room to do this, its only the sides I'm restricted due to narrow width). Then the window will all sit symmetrically 'correct' to the walls around it.

I was wondering if I even need to line the reveals at all. I mean they're all "lined" with 100mm of timber as it is being a TF build, plus a sandwiched 25mm PIR layer I put in next to this 'frame' around the window, then another 50mm timber stud outside of that. The window would look 'correct' if I could just put pB directly onto the timber sides. I could then just PIR line the top/ btm with a full 25mm. Surely timber has thermal properties itself of a sort, or big log houses wouldn't be inherrantly warm.. chalet I was once in switz was warmest house Ive ever known.. just one skin of big logs afaik.