Ok. Well thanks for your comments so far! Sorry about my essay. I do write too much. It's just been such a palava and it's hard to put across the stress of the whole affair without describing the problems we've had.

I got a text message quote from a local plasterer today for £1700 for the external wall to be rendered in lime putty and sand 23m² + vat and £230 for skimming the plasterboarded hall ceiling.

I've asked for a more detailed quote, asking specific questions, like, what materials will be use, e.g. the above mentioned and his basic method, e.g. thickness, 2 or 3 coats, plus lime finishing skim. Also, whether we need to have the gaps in the brick lime pointed first?

I am expecting him to disappear into the ether, as he's clearly a man of few written words, but he said he's worked on graded buildings and such. Seemed to know lime when he came round. I just can't risk any misunderstandings and leaving materials to chance after all the research I've done.

I was all set to specify Lime Green Ultra but I'm not sure we'd gain much of its famed insulative value, as the data sheet talks of building it out in layers, to around 60mm maybe or more, and we would look at having 20mm plaster thickness (string width 30mm). It's also made up largely of NHL lime and the lime group I'm on on FB is condemning NHL at the moment, as evidence is mounting that it is looking to harden (over time) to similar levels as cerment and not carbonate as well as fatty lime putty for breathability purposes, or the holy grail of hot lime!

As for the gaps around the floor to the sub floor... There are several bricks broken, especially near the front door, with some missing and you can see the outside airbrick with relative ease if you get to floor level.

I bought some rolls of sheep's wool pipe lagging 75mm width and had the idea to push it down into the gaps before fitting skirting. I figured as it's breathable, any moisture that may collect on it, could diffuse down and be dried up via the cross air flow below the floorboards? I'll post a pic...

Front right side of the external wall near front door, gap in floor and gaps in bricks.

Front right side of the external wall near front door, gap in floor and gaps in bricks.

Other gaps around for perimeter this time internally near kitchen door along the under stairs cupboard.

Posted By: BiscuitsAndTeaI've asked for a more detailed quote, asking specific questions, like, what materials will be use, e.g. the above mentioned and his basic method, e.g. thickness, 2 or 3 coats, plus lime finishing skim. Also, whether we need to have the gaps in the brick lime pointed first?

I am expecting him to disappear into the ether, as he's clearly a man of few written words, but he said he's worked on graded buildings and such. Seemed to know lime when he came round. I just can't risk any misunderstandings and leaving materials to chance after all the research I've done.

It seems like you're getting to grips with things quite quickly, which is good. Equally you appreciate the individual motivations of the tradesmen, which is also important. We found cake and tea are also important

It's also made up largely of NHL lime and the lime group I'm on on FB is condemning NHL at the moment, as evidence is mounting that it is looking to harden (over time) to similar levels as cerment and not carbonate as well as fatty lime putty for breathability purposes, or the holy grail of hot lime!

You don't want to believe everything you read on FB of course, or anywhere on the intertubes. But there are various degrees of NHL and the more 'eminently' hydraulic you get the faster it sets, even under water (hence the name and purpose), and the less breathable it is. Whether that means it's better or worse depends on your application of course.

As for the gaps around the floor to the sub floor... There are several bricks broken, especially near the front door, with some missing and you can see the outside airbrick with relative ease if you get to floor level.

I bought some rolls of sheep's wool pipe lagging 75mm width and had the idea to push it down into the gaps before fitting skirting. I figured as it's breathable, any moisture that may collect on it, could diffuse down and be dried up via the cross air flow below the floorboards? I'll post a pic...

When it comes to floors, and indeed in general, you need to keep airtightness (and ventilation) in mind as well as breathability and insulation. With floors life is especially complicated, since you also need to think about the effects of liquid water - spilled coffee or a more serious flood. Sadly there are no correct answers - you have to work out your own compromises. But water permeable insulation has many advantages underfloor, and as long as the underside isn't 'wind-washed' doesn't need special treatment underneath. You will want something that is airtight above it however.

Wind wash is when you have a wool type insulation (glass fibre, rockwool etc.) and you have a draught blowing over (under) it. This disturbs the air trapped within the wool and allows heat to be removed as a result of the air movement. Loft insulation can be covered with paper or if multi-layered then paper inserted below the top layer to mitigate this effect.

Air tight layer above the under floor board insulation = plastic sheet.

Reference sheep's wool. You have to be very careful to avoid insect infestation (moth and alike) and sheep's wool can be treated chemically to prevent this but it is not always 100% effective. The 100% cure for insect infestation of sheep's wool is to use glass fibre wool or rockwool.

It seems like you've been plunged into that retrofit spiral; one thing uncovers another which uncovers another.

As already mentioned getting hold of trades for work right now is a problem pretty much everywhere and they typically aren't that great at communication. Be patient and persistent and you'll eventually find someone, or you'll change track.

I don't think building control is an issue here at all and wouldn't worry about it.

I won't comment on the wall plastering other than that you've experienced lime purists in that nothing other than the classical non-hydraulic is any good. Don't worry too much about it.

On the wall floor junction, I guess you're not planning to pull up the floor to add any insulation?

If that's the case, then focus on airtightness. Your sheepswool won't do much for that, even if it's a nice material. What I would suggest is that you just go and buy some mortar from the local diy/builders merchant, use a bit of plasticiser to make application easier if you haven't worked with mortar and then fill the large holes in the wall. It looks to me like someone has in the not too distant past replaced the floor joists and lazily not remedied the wall, instead hiding it. You can set the loose bricks in place as best you can - again a simple but fiddly diy job.

Then, to provide airtightness, your easiest best is something like Saudatight LQ liquid membrane with the Saudatight Geotextile which will bridge most gaps between wall and floor and it's easy to apply with a paint brush. This membrane is paintable and plasterable so you can put it in place and then when the plasterer comes to do the wall, the upstand can be covered by plaster.

HTH.

There is a startup called Thermulon which aims to make an affordable lime and aerogel plaster which would be ideal for this project. However it is still in development. I have an interest, having just invested on Crowdcube. But I see it as a game changer for solid wall insulation when exterior insulation is not possible.