Redbeard

Well, from what I can see from your pic the only bit which will be unsupported (ish) is round the waste, and you probably don't tap-dance there. You couldn't have filled completely with sand/cem anyway in case you ever need to work on the waste (from the room below). Having it encased in mortar would be a trifle inconvenient. I cannot be sure, but if you do your 'croupier' bit carefully I think you may be as OK as you can be. How not to 'croup too far' and bed in the waste? Perhaps measure carefully and jam in a piece of timber (not so tight as to lift the tray, but then you could trap it sideways between the exg battens) against which you can 'croup' (It's my verb and I will use it!!). Sorry! P.S: Did the fitter have those instructions?

Open up and hack out a bale. Of course it's not as easy as that, and you might have to resort to 'flakes' (the 'sections' which appear when you split a bale, but in order to carry render, even with the help of the mesh, it needs to be really firm. Don't know how it was built but even if it was not ratchet-strapped it has had the weight of a roof on it, so if you take out a (compressed) bale the replacement bale will be too tall. Experimentation is the order of the day (and yes, I have had to do it. The 'wrangling' may make a bit of a mess of your render... Assume you or your group have 'Building With Straw Bales' (in UK) by Barbara Jones? Not much on repair but a great 'primer'. https://strawbale.com/repairing-water-damaged-bales/ (not a UK site but looks OK the few words I read on repairs)

Hmmm... so the tray is already fixed in. You do want to bed in a semi-dry mix of sand-cement as per the instructions you posted. My tray was not raised on a frame so I had to guess the height of the s/cem mix and luckily got it right. In your case you could just use a T-piece of wood/ply and push it in like a croupier shifting chips (no, not the edible ones).

Think I have lots of stop beads but again, the killer will be carriage. I'd try EWIstore. I have found them very helpful.

Depends where you are. My local builders' merchant (in Yorkshire) sells them. Screwfix do them - 5 x 2.5m for £33. https://ewistore.co.uk/shop/external-wall-insulation/white-corner-bead-no-mesh/ do them for £3.59 each but no doubt carriage will up it a bit.

If I had any lime putty I would do quite a putty-rich lime putty/gritsand mix, say 2-2.5 to 1, to make it nice and sticky. Lime putty is hydrated lime, but it's not the (dry) hydrated 'bag-lime which is mainly used as an admixture to sand/cement to improve plasticity.

Can I suggest a point 4? VCL over the lot.

Oh! Is that not plastic soil pipe? It looks very like it, and there appears to be a 40mm-ish spigot at the back, against the wall. Maybe all is not as it appears. So the 'plastic soil pipe' is metal flue pipe and the 'spigot' isn't a spigot?? I certainly would not use foam. Pack it with dense Rockwool as used for EWI fire-breaks and around flues.

Is that newspaper I see round the waste branch? Probably try pushing in quite a sticky lime mortar as a base. Don't know what the Mapei primer is and whether it would be compatible with the 'breathability' of lime.

My front garden retaining wall ('inherited' as quite new in 1987) was, I am sure, built as cheaply as it could be, inline with all other 'renovations on the house. I am convinced it is 225 brick only, and it retains between 1200 and 1800 over about 10+m. It has no weep holes, and it's fine. It shouldn't be, but it is, and if (as per my earlier Q) you wall is actually as strong as 112 brick and (??) 100-150 stone then it may fare as well as mine still is. I suspect mine will last till after I am dead, which is all I need. Is that stone laid dry, or can I see recessed mortar? That (given I cannot see a batter or 'lean-back') may be an important issue.

But isn't that plot hugely wide compared to yours, even if you could buy the passage? (and you would be a very 'captive audience' for that).

Welcome. Some people would say MVHR is an essential adjunct to a very a/t house, while others would say simply don't bother with it unless you are looking for a/t of less than 3ach. Others still say that it can make sense at up to 10ach provided you've got a low specific fan power (SPF). And lastly some with respiratory issues say 'MVHR massively increased my comfort in the house'. Choose your explanation, but you are doing it anyway, so I hope it goes easily, and don't forget the attenuators (and smooth ducting if you can).

How deep is the stone skin? Is it tied in? The 2 skins together might make a fair wall. I remember when building my not-much-more-than-1200mm retaining wall to an SE's dwg it was (/felt) HUGE at the base (?685mm?). Remember thinking that if I really wanted to survive a war I could just try burrowing behind the wall. What you show looks very spindly in comparison.

Yes, but they appear to be 'wet-fixed' ridge tiles, which seem to me to look soooo much better than dry-fixed.

As I sugg'd, see if you can get something from the manuf'r saying 'this is not how it's done' and send that when you send your statement saying you will not pay for that element of the work until it is done to a standard which would be seen by the manuf'r as satisfactory. (Manuf'r may not want to put their head that far above the parapet, but they should at least be prepared (I would imagine) to say 'that's not how *we'd* do it.'

I think lots of BCOs are requiring 'dry' and mechanically-fixed ridge tiles now. You may have to live with the colour, but I am a believer in straight lines... Do you know the make? If so send pics to the manufacturer and ask if that complies with their expectations. Then invite the contractor back to tell you to your face that that is a good job.

I'll get me coat...

😂 No...it sounded vaguely funnily like Dee Dee Ramone but with a little DIY moan mixed in. I must be being a bit dim also because I'm not sure what you're referencing? I'm aware of MZ bikes and the former East Germany but it's like one of those questions on the 1% Club where your brain just won't make the connection! 😂 Sorry, a bit tortuous, but the former East Germany was the 'DDR' (Deutsche Demokratische Republik), so a 'DDR moan' might be a grouse about that former country. I obviously lived too long with MZs (11 of them IIRC!)

4 hours ago, saveasteading said: I didn't know this. Can you explain why the toothing helps get it flat? As a poor plasterer, I like the products with a high latex content. It is stickier to the wall, less effort to float and takes a while to go off (for second chances) Nod said: It doesn’t base coat needs to be flat and lightly scratched Think he’s getting mixed up with top coat A toothed feather edge is used to get the air out Then flattened back down Sorry, I was not assuming much 'out-ness' on the substrate. The toothed trowel approach (which I always used for plastering and rendering on wood-fibre) does not get it flat - simply helps you keep even as each subsequent coat goes on, so yes, you do need to get the first coat fairly right. Bear in mind I am talking about renders and plasters designed for thin-coat application, not at more 'traditional' thicknesses.

@nod is right, but if you are really wanting to do it yourself the 'toothed trowel-depth-guide' method works. I think perhaps my description is more complicated than the doing. Just a bit of practice so as not to try to 'go over' when the coat below is too wet.

I think I would be tempted to buy some base-coat EWI-type render. If you have never done any before I would suggest use a 10mm toothed trowel, then let that coat stiffen up a little before doing a second coat with an ordinary trowel. The 1st coat will act as a guide for the 2nd. You may not need mesh but I think I would use it. Lightly 'float' the glass-fibre mesh over the 'peaks' of the toothed coat , the=n trowel on render till the mesh is no longer 'ghosting through', or as close as you can get. You may need to do a final base coat to lose all the 'ghosting'. Final final coat (after 4 days, IIRC) is self-coloured top-coat 'gritty' render. Lots of people sell this stuff - sometimes local merchants, but I have used EWIStore a lot.

You didn't ever have an MZ motorcycle that you were dissatisfied with, or a grouse with the former East Germany, did you? Your user name might suggest it!

Welcome. 25mm of (breathable) wood-fibre could give you a U value (heat lost in Watts per sq m of building fabric per degree C.) of around 0.85W/m2K - around half of the heat loss (1.7W/m2K) for the uninsulated wall. Better than a poke in the eye with a sharp stick but the Bldg Regs target of 0.3(or as close as you can get without seriously risking interstitial condensation (condensation within the slices of the insulated 'sandwich') ) is a lot better. 100mm would give you about 0.35.

I had not noticed the ref to opposite directions - in fact I still cannot find it. Sorry if I missed one. All I saw was this: ...so in my mind there was as much a chance of 'hills' and 'valleys' lining up (leading to effectively no increase in depth) as there was of 'hills' and 'hills' coinciding (10mm either way and you get a different result). If you do it each at 90 degrees then maybe you could let one coat stiffen up a bit first? (Still not certain what depth you'll end up at when it 'sits down')

I use a 10mm notched trowel when I want a 6mm-ish bed, as the angle of the trowel 'closes it down'. A 6mm trowel 'closes down' to about 3mm depending on the angle.