Redbeard

I don't know which bit of NW you are in but have you tried Manchester-based People-Powered Retrofit for pointers?

Title's changed - too late!! 🙂 Sorry...

Am I allowed to say anything about garages and marsupials?

Is your garage really brick, or block. Just that if you are looking to render it it seems to be an expensive way to build...?? Uselessly, cannot answer the render Q, I am afraid! I think my first port of call would be to ask the manufacturers/suppliers of EcoRend.

But ST, that was probably ever thus to a very small extent, and, though traffic is lower, there is still some good knowledge and good debate on there. I am not a regular reader of other forums except this and GBF, but I guess any forum has to 'gloss over' the grumpy and (sometimes) the misleading.

Still there!

Years ago I had the most basic Black and Decker model. (Maybe think cheapest 'own-brand' from SF or TS now). I made my own windows, routed details on existing windows and generally used it a lot. I killed it in the end but it was fine. Just for an edge on window boards I'd go cheap-but-'known'. I bought a very cheap paddle mixer from a hitherto unknown source (I have stopped contracting and have just a little of my own stuff to do. My long-standing mixer died just at the wrong time) and, though it works, the quality is truly pretty awful. It does mix plaster but I would not normally buy something that grim.

From Eco Therm's website: "Eco-Versal is a 5 in 1 insulation board with a thermal conductivity of 0.022 W/mK. " The relevant values are the thermal conductivity (Lambda) values. In both cases they are 0.022, so the Eco Therm product will give you the same result. Yes, 100mm Celotex will give you a (not very exciting) U value of 0.22 for the insulation only, but so will the Eco Therm. This figure does not take into account the perimeter/area calc, but the 0.13 U value does. So Celotex will give you 0.13 and Eco Therm will too, using the same calc. Therefore the minimal extra cost will be a minimal extra cost for exactly the same result.

How old is the house? Could some of it be lead paint? Check the precautions required

Don't expect much acoustic performance from PIR. Density is your friend there.

60mm wide is generally what you'll get in UK, with 150 for taping holes for Warmcell-blowing. I used to get 100mm from Baunativ (now less keen to supply to UK, or were when I checked) which has a split backing tape. I rip it down to 50mm. For general use that's enough width for what I need it for. Leave a roll 'un-ripped' for any areas you need wider.

Insulate the lot with rigid wood-fibre. You can probably wrangle (3-4) layers of 20mm round that curve. Finish in lime. I find the Baumit products very easy to use if you are not used to lime.

Not quite an answer to the Q you asked, but perhaps to part of it. I have done a few 'pragmatic' floating floors on XPS (30 and 50mm), on PIR (25 & 50mm) and on rigid wood-fibre (200mm). In all cases I used 18mm T&G OSB (2400 x 6600) over, glued at all joints. You would have no reason to know that they were floating floors. They all feel so solid. I have never used phenolic in a floating floor. The latest floor (the wood-fibre one) will have final finished floor of T&G OSB too. I think that one might just break the 'floating' rule, in that I feel I might put a few screw fixings into the previous OSB layer. I will start another thread sometime for recommendations on varnish for the 'finishing' OSB.

Sorry, this is not a response to the noise issue, but can I make a suggestion re the insulation? If the MVHR unit is in a cold loft I would suggest that 25mm EPS is insufficient for its 'shed'. Better than nothing at all, definitely, but I think I'd go for significantly more. Actually, while writing that a thought came re attenuators further to @jfb's comment. Think motorcycle or car silencer if you DIY and don't want to do it with OSB. Offcuts of different -diameter galv ducting, drill-bits, thin sheet steel and HSS drill-bits (and the rockwool mentioned) could fit the bill.

The insulation alone will give you an R value of 9.0909m2K/W (U of 0.11W/m2K). You could do a perimeter/area calc to estimater the 'base case' U value of the un-insulated floor. Add the reciprocal of that to the R value for the 200 PIR and you have a reasonable estimate of the complete 'structure and insulation' U value.

Just plant some buddleia and I am sure you could get a 'similar' result!... It is even a job creation measure, in providing future work for builders and structural engineers.

Are you planning some internal insulation in the walls? If so, have an insulation upstand from the under-floor insulation to just above finished floor level, so that your internal insulation can connect tightly to it. I think I'd do an upstand in any case.

... and very little music that you don't like!

@Sparrowhawk, BCO becomes interested in U values when you are 'renovating' (adding or replacing a layer to) more than 50% of a thermal element, and that's not 50% of, say, all the walls in the house, it's the external wall(s) *in the room you're stood in*. For example if you rip off the plaster from the one external wall in your inner terraced front room, you arguably have an obligation to insulate to meet the requirements of Part L. I have found that if I am using (thin) PIR, BCO wants to see 0.3W/m2K, but if I am using wood-fibre with an insulation value only just over half as good, BCO accepts arguments re trad building and 'safety' re interstitial condensation risk.

To put it in context, think of all the recent coverage re storm water overflows leading to overloaded sewers and spillages. Yes, your roof is only small, but many many thousands of small roofs = a lot of water into combined sewers. I was surprised when I contacted my water authority (one of my fall-pipes draining approx 50m2 of roof discharges to soil with rock below) to be told 'yes, it's fine to connect to the combined sewer'. I realise that I have less chance of a soakaway soaking away than many, but even so...

@saveasteading said: ''The point of sips is that it structural. I don't see the logic of oak plus sips''. My thoughts entirely. Assuming you want to keep the frame 'on show' internally why not spaced-stud out ('Larsen trusses') and fill with flexi wood-fibre, with whatever you want as a finish structure or board on the outside? (and you asked about footings - sorry!!)

Thanks @kandgmitchell. For clarification the 'other hinges' we got were still 'Reflex'-type - they look the same as those in the pic, but the bit on the RHS, which is I think 'captive' in your pic, could be made to slide across to the extreme R to 'optimise the orifice'.

This is from a 2010 doc from Lancs Bldg Control (first hit I found - not aware if it has been superceded. Looks about right for what I remember of last time I had to 'prove' one: "Achieving the requirement. The window should have an unobstructed clear openable area that is at least 0.33m2 and have no clear dimension less than 450mm high and 450mm wide (the route through the window may be at an angle rather than straight through), appropriate escape catches and hinges must be fitted to ensure this clear opening is achieved." We had one queried some years ago because the reflex hinges, like yours, brought the 'hinge side' of the opening light into the aperture. We were able to buy alternative hinges (the exact operation of which I cannot remember) which allowed one to push the window over (to the far right in your photo above) 'in extremis' to widen the aperture. (I hope I have not made myself abundantly unclear!) Have they given you details of their objection?

I find general building dust is often just the right colour! (Or else turns the red grey to match the rest!)

"On top of all that, my beard seems to be going grey with all this stress. Gaaaghh!" I greatly sympathise. My user name is not 100% accurate!