Redbeard

Power-Pipe UK | Waste Water Heat Recovery Systems A Power-Pipe® recovers the heat energy lost down the drain during showering and uses it to pre-heat incoming mains freshwater. Saving £ + energy. No, I didn't know either!

I took 'bare walls' as meaning that the walls were stripped back, whereas in fact 25mm is pretty thin, but as your experience shows it is on the 'steep bit of the curve' in terms of insulation efficiency. Nevertheless, since you do not have what I thought was a 'blank canvas' (to 'engineer' a lay-up with both insulation and support) I suspect the answer is to fix battens for the units through the insulated plasterboard, doing your best to make good the VCL which you puncture (a 'liquid grommet' of silicone is the best I can suggest, or small 'tabs' of EPDM or butyl tape) and then make sure your screws through the back of the units go no further than batten depth + plasterboard depth. If your insulation were much thicker I would be worried about torsional stress on the screws but 25mm is pretty minimal. Edit: Just realised this is still in the 'introduce yourself' section. OP, you may want to see if the moderators can move it to the correct section, where it will be more accessible for others searching re similar issues in future.

Is the kitchen below? Can you drop the shower waste down and take it out at GF ceiling level, or even GF level?

I think the only 'perk' would be that if he did go self-employed in future there is a small income tax offset allowed for use of home as office. I think the top rate (it's based on how many hours you use it) is £312 p.a.

we----ll... It depends whether you follow the school of thought which says that a hole with a screw in it is not a hole. If you share my pessimism (that it might be; a bit) you could fix through little squares on EPDM or butyl tape which sort of 'self-heal' around the screw more than membrane does.

Crazy thought but... ?Bubble-wrap?!!

Splendid user name!

Could it be that (though Victorian) the bay is of cavity construction? I wonder if potentially that air-brick is venting a cavity and at the bottom of the hole (under the stone plinth) is the air-brick which should be venting the floor void. (Not sure how that works with the proximity of that drain, though).

Mineral wool: Worse lambda value - completely non-combustible. EPS: Better lambda value - combustible but protected by render layer. If you don't like using plastics go for RW. Note that you would not use RW down within the splash-up zone. That would be High Density EPS or XPS. I have never seen PIR suggested as a 'below DPC' plinth layer, and certainly would not choose it myself. PIR is not generally used for EWI, to my knowledge.

Without moles.

Agree, we need pictures of the curves. If you really need to follow a curve then (a) it depends on the radius and (b) while plasterboard can be persuaded to follow a curve, insulated plasterboard would need slots cutting out of the insulation, making efficacy and continuity a bit iffy. Flexi-something followed by something like Intello membrane and 'steamed' plasterboard. As far as If you are concerned re over-enthusiastic 'stuffing', staple some breather membrane between each rafter pair, 50mm from the felt. Stretch as tight as you can and then you can 'stuff' with abandon. How about using 'Larsen Trusses' ('poor persons' I-beams')? Basically a sub-rafter hanging below the existing (parallel or at 90 degrees). The latter would help if you really need to achieve a smooth curve.

Re video: Strewth! That's more flex than I have ever seen, but it is bigger than any single pane of mine. I can see why you are concerned!

Well it depends on whether you take your view or theirs. Yours, I think, is that although you took all the walls down (the front one having nearly fallen down, I accept) this is not a rebuild. Theirs seems to be that, since they were able to take pics of a cleared site, it obviously is. If it is, it needs to comply fully with new-build Building Regs and Planning requirements. That would, for example, one assumes, include all-new foundations. You do not mention foundations, but I think the suggestion is that the walls have been rebuilt on the existing ones, which may not (or may) be deemed sufficient.

Re getting a letter of support from BCO, I have no idea whether the Planners would take this into account but it cannot do any harm. At this stage you need all the offers of help you can get.

Quite simply it may not comply, although it might... As I mentioned above the way of assessing compliance (or not) is different for extensions and new-build. What do you have at the moment in the way of drawings and specifications. What were your insulation values going to be in the extension? How about the existing house? Presumably the intention was to upgrade that too? How? (External insulation of walls? Internal insulation? How much in the roof? Are there rooms in the roof or is it just a wide open space? (The latter makes it easier for you/your friend). Give us as much detail as you can. Probably air-tightness is going to be the biggest difference. The whole (new-build) house will have to achieve better than 8m3/m2/hr. This is not exciting by many standards, but it's better than a lot of existing buildings achieve.

I had based my comments (as had @joe90, I think, on your post above: So 150 is the max, but due to the random wall construction it goes down to 50? I now understand why you are concerned about losing more space.

Have I misunderstood? I thought you said your studding was 150 from the wall. A reasonable gap would be 50mm, so you could get 100mm insulation in and add a service void while losing 40mm at most. If you are prepared to have wiring on internal walls only you don't even need that.

Looks good, particularly if you do not need much. Otherwise you buy 25kg NHL 3.5 and a fair old lot of sand (depends whether you are mixing by weight of volume, but crudely 25 kg, or 4 small bags from DIY stores. Fine if you need that much.

Yes, I gave the example of 'dot 'n' dab', but if there is any external air-leakage into the cavity behind the plasterboard then you have brought the 'outside inside, and potentially you could have just a half-inch of plasterboard between you and air at external temp. I was going to suggest insulation, but @saveasteading already has. I more usually used to insulate 'hard to the wall' on a lime parge coat, but fixing through granite sounds like it would be ... fairly challenging!

It describes a 'syndrome' where you get unwanted cold air circulating on what should be the 'warm side' of the wall lay-up. The most typical manifestation is 'dot 'n' dab' - plasterboard fixed to a wall on blobs of adhesive with lots of hollows between. Any air leakage through gaps in the wall may get through to those hollows - That is a 'plasterboard tent'. In your case I think @joe90 was referring to the apparently very (air-) leaky stone wall with the void betwen it and the hollow-fixed pl'bd. *Ah! I see @joe90 has just replied. I'll post this and maybe find we have said the same thing!

Possibly 3: 1 grit-sand and NHL 3.5 hydraulic lime may be easiest to get. If you have a lime supplier near you you could ask their advice. NB: *Hydrated* ('Bag-' lime) is not what you want. That is used mainly as an admixture in cement/sand/lime mixes.

Struggling to work out what bond that might ever have been. What does it look like on the outside? The reason I ask is that on the inside the RHS of the lintel seems to be sitting on a pile of bricks. I suspect that half of those I can see are through-bricks, which makes it less scary, but it still looks like it's not held together by much! In the light of this then any mortar is better than none at all, but you are right, the original is likely to have been lime. The lintel bearing would not meet today's standards but neither does that automatically mean it is 'going anywhere'.

You may find you need a surprising no. of holes. Typical 'strip' eaves vent allows 25mm of clear vent path, so 25,000mm2 for each linear metre. If doing holes a typical 70mm round fascia or soffit vent gives 2000mm2, suggesting you'd need twelve-and-a-half per m. I don't usually use round vents but when I last checked them out we were amazed how many we'd need - many more than the contractor had proposed to fit.

To what insulation standard? If it's a refurb then the U value targets are elemental - a wall needs to be this, a roof that, etc. New-build is treated differently and it's done via a SAP (Standard Assessment Procedure -for the energy rating of buildings) assessment, comparing the CO2 emissions you will achieve in your build (the Design Emissions Rating - DER) against a minimum target (The Target Emissions Rating - TER). Can you confirm what thermal standards the walls, for example, have been built back to? The extension is not an issue because extensions are assessed elementally, too, and the target is 0.18W/m2K. How about the walls which were 'existing' till they got knocked down?

I was just thinking how nice it looked, and how little the Fire Officer would like it... Edit: And then I saw the other posts below! Sorry! Been there; done that.