Redbeard

Would the planners be interested? Surely this is a Building Control and Compliance thing?

From bitter experience... if you use a hot air gun (on low!) wear gloves. If you get it too hot your fingers will break through the oter layer into the molten hot butyl. It sticks and it burns. Can't tell you how I know.

dpc? I guess...

I could be wrong but I believe that a lot of cavity wall insulation companies are members of a self-certification body, so they can sign off against Bldg Regs. However I feel pretty jolly certain that they could not sign off a job which was not a cavity wall.

Yes, I think you need BC. You already have the calcs so do a Building Notice, which is just a pro forma telling them briefly what the works are and when you will start (no less than 2 days from the date of the notice) ... and a fee. I have not read all the thread but it is structural work. Any that I have ever done has needed BC approval.

Hi, when you say that do you mean you feel you have no recourse to the builder? Or does 'we...' include the builder re-doing the work? It is not ideal but while you would almost certainly not get a satisfactory result by patching you may be able to re-coat entirely. Not that I am recommending this at all, but 16 years ago an apparently well-thought-of insulation company managed to quote for 50mm phenolic EWI (which would then allegedly have given a U value of 0.35W/m2K). They then had their sub-contractor (part of a nationally-known company which subsequently dissolved) do the installation. The sub-contractor used 40mm board. When questioned I was told 'we always use 40mm board...! What they should have done then is taken it all off and done it with 50mm. What they actually did was to adhere 20mm phenolic on top of the top-coat and re-render. While I cannot commend this slap-dash approach what it does prove is that base-coat render has a good hold on underlying top-coat render after 16 years. So if you hold any money owing to the builder you could, after consultation with the System Provider, consider asking the builder to have a trusted renderer do it again (base-coat and top coat) over the existing... (Or tell them to hack the lot off and do it right. Is it on EWI or block?)

Yes, but cob has worked for hundreds of years in the UK. It has also failed spectacularly where modern materials (sand/cement renders) have been used to repair it. Yes, it is 'newer', but there is at least one straw house in USA over 100 years old and many an awful lot older than 20 years. Straw bale in the UK is pretty young, so yes, 20 years may be 'the norm' in UK, but arguably (and I haven't checked the true figures) because the 'start' was only 20 years ago. It doesn't mean they won't last another xxx years+. You are right that lime and a big roof oversail will help a lot.

First hit on 'Neighbour consultation permitted development' gave me: https://designfor-me.com/project-types/extensions/what-is-the-neighbour-consultation-scheme/ So a 3m extension will not be consulted upon with your neighbours, and a 6m one will, AFAICS. I do not know any more about the specifics of the consultation procedure - can a neighbour somehow block a development, for example - but there is an appeals process, it appears, so I am guessing that a 6m ext'n is not a 'done deal' till it's 'done'.

Very well done! I'll stand down my tape then!!

Is Ubakus German, or did I make that up?! If it is, I wonder if they do not use the IP/90-type Perimeter/Area convention, which gives a lower 'base case' U value than the old 'Uninsulated floors are 2' - IIRC then you'd expect a higher U value. But then I may be talking rubbish since, even if it's German, this appears to be the English version, so maybe it does use IP/90

(Sent PMs)

Packers for slightly-out-of-line studwork, I had assumed.

Bu**er! That was my favourite! Hope you find it.

This?

I think last time I did a B. Regs app with more than one element the cheapest one was halved in price, so in your case it could be £809 + £275.50. I think I would be tempted to do it on a Building Notice (Simple Bldg Regs app with a brief descr of works and no other detail) rather than Full Plans, but then I'd be building it myself. Depends on the degree of complexity and how much you trust your builder. Planning looks like it ought to be really simple, I *think*. You could draw that, and thus do the Plg app, yourself, perhaps. Re struct eng'r I suppose you'll at least be changing lintels, if not roof timbers, so yes, you need them, I think.

I would have said mortar, had I not assumed that you were looking for a very quick fix.

I take your point, but if you look at it in the context of a whole-house plan enacted over a very long period (possibly finished by the person(s) after you), there's still logic in getting the best you can from each element that you do 'enact'. I fully expect my refurbishment to be finished sometime after I am dead! Depending on how much work you are doing yourself the actual 'spend' could be as little as the cost of an extra 50mm. Agree also with 50, not 25mm upstand at perimeter.

You are asking for comments on the TF, but may I ask about the floor? What U value do you get with 100mm PIR? Could you fit 150 in (or even greater thickness and use graphite EPS instead of PIR)? Will you have under-floor heating? If so others will be along to highlight the greater delta T (and therefore the justification for more insulation).

Epoxy, or CT1, which my former colleague claims will stick more-or-less anything to anything! I don't know anything about Soudal Plasterboard Adhesive but wonder if an adhesive made for a dry indoor environment would do well in a wet outside one... (Happy to be proved too sceptical)

Agree with the comments above. I am sure there's more to the process so far than I read, but it sounds like *you* have come up with a compromise so that *they* can get PP. Not sure where the 'balance of power' is there, and agree with others that you should at least look at the issue of future sale now, before development, whatever the 'inducements', even if your ultimate conclusion that it will sell with no probs. It sound like not a fun position to be in - literally - and I wish you luck with the outcome.

The plastic is a Vapour control layer (VCL) which is designed to stop 'interstitial condensation (water vapour condensing out in the insulated wall 'sandwich). Unless you are planning to change completely the 'moisture behaviour' of your Mum's house no, you do not necessarily need to remove it, but if you are adding more insulation internally you might, as you would then install a VCL on the 'warm side' (just behind the plasterboard) of that new insulation. Edit: Was typing while @Crofter typed.

PIV = Positive Input Ventilation, as described by Andehh

ST = Buildhub member @SteamyTea dMVHR. Decentralised mechanical ventilation with heat recovery. Decentralised because he's not talking about 'full monty' MVHR systems which have a central heat exchange unit. dMEV (decentralised mechanical extract ventilation) involves using specifically-designed fans in wet areas (bathrooms and kitchens) which run permanently at very low wattage (perhaps less than 2 Watts). They also have an over-ride (pull-cord or - my preference - humidistat) which kicks the fan in when things get too steamy. They rely on having open vents (often 'trickle vents in the window frames) in all the 'dry' rooms, so that the extract from the wet rooms causes supply air (from outside and usually more dry) to flow in. It's very simple with no complicated 'control interfaces. CV2 is simply the model number of the 'Greenwood (manufacturer) Unity dMEV fans I have bought.

Agree with ST's dMVHR suggestion, but if you want to go a bit cheaper and forego the HR, decentralised mechanical extract ventilation (dMEV) may be an idea. Some have spoken of it highly on here and I have 3 Greenwood Unity CV2 units waiting to go in.

Some would say not. Like base-rails for EWI, some like a 'proper base'. If your upper layer is to oversail the brick slips it will still need a drip at least, to reduce the risk of the worst-case scenario which is water tracking back into the junction of the 2 layers.