SimonD

I didn't really mean the scientific explanation of the experience of temperatures, I was more referring to how human beings tend towards illogical behaviour when it comes to how they deal with their experience. E.g. walking around in shorts and a t-shirt in the middle of winter in the house and saying it's chilly and ramping up the thermostat instead of just putting on some trackies. Likewise we see the same thing in studies around heating and ventilation systems. For example, some large scale studies found that the monitoring systems were showing abnormal behaviour in MVHR systems being studied, looked everywhere they could to try and find a problem, but it wasn't until they asked the residents when they found out they were all opening their bedroom windows at night - a relic of the country'culture. We see the same thing with heat pumps where the users don't bother to find out about how the system works, instead expecting that the system behaves as they've always done using bursts of high heat twice a day. You also just need to look at the surge in wood burning stove installations when gas prices rocketed, without much consideration to how that might impact solid fuel prices and the logistics of keeping the stove, sotring the fuel, etc. etc. and that it really isn't any cheaper than gas at all. The other day I read that scientists are finally realising that a lot of the problems we're experiencing with climate breakdown, consumption and environmental damage has to do with people's behaviour and that we need purposeful behaviour modification, however sinister that might sound!

I think we're all illogical when it comes to temperature and almost everything else behavioural 😊, but I was just talking to a customer about this the other day. I'm exactly the same, with the heating cranked up even when it shows a health 21C in the house. Our system has a cold weather boost where it increases target temp by 3C during cold periods, which is supposed to be for draught ridden uninsulated properties, but seems to be the perfect solution for us right now!

As I think @SteamyTea is alluding to, I don't think you have a problem with moisture, or moisture in the wall per se. It's just that the wall is sucking too much heat out of the space, and will continue to conduct heat even after a long period of acclimatisation. Due to the nature of the wall itself, you'll always experience it as being cooler than the surrounding air - a very pleasant property during a heat wave,not so much in the depths of a cold winter. I have heard some people suggesting that the interior finish has a great impact on the experience of thermal comfort in the home, some of which has come from those selling woodfibre IWI, for example. I've heard it said that this is because of how the material bounces infrared from its surface and apparently woodfibre returns these to the body to make it feel warmer - I suspect this is a brilliant example @Iceverge's definitions above and could be added to those. Why do I suspect this? Because downstairs in my house I have masonry walls with just a gypsum parge coat internally (my 140mm woodfibre insulation is EWI so not relevant to the IR claims) and upstairs I still have mostly OSB. Neither feels more or less comfortable than the other with the temperature and humidity remaining the same. The only time there's a difference is during very hot weather and downstairs remains beautifully cool for days during heatwaves. Now in your instance, you will also have your wall contributing to your RH, even if it isn't wet or damp. If you use ventilation to try to reduce humidity, the wall will simply give it back to the room. If you had a wall lined with PIR, this wouldn't happen and you would see a reduction from extract ventilation (see paper I linked to above which measures this process). I'm sure I'm not new in suggesting the solution is to insulate, but then the question remains as to how. Generally the concensus is now verging to using a buildup of materials that largely behave in the same way as the wall material and this doesn't require a ventilation gap between the wall and the insulation layer. So your options could be to use just a thin layer of insulating plaster which can be lime based, or even lime and cork like SecilTek ecoCork, for example, which is then finished using a lime render. Alternatively, you could look at IWI in cork, woodfibre, or even sheeps wool (sheeps wool recommending a breather membrane against the wall between the insulation and wall). Each of these will have different buildups with the cork and woodfibre generally being stuck to the wall and then plastered. The sheepswool is installed between battens followed by vapour control/airtightness layer, then plasterboard and skim if you want to. If you wanted to try ecoCork, and your wall areas isn't too big, I have about 33 bags of it surplus to requirements that I'd be happy to let you have - I just don't know the expiry date on these and hope they's still be okay as they've been stored for a couple of years now. This is just covered with a Seciltek render to finish. Then there's the hempcrete spoken about earlier. There are then those that are quite happy to put PIR on the wall, but generally this is now only recommended with a ventilation gap between the wall and insulation. TBH, I don't envy you, I once loved the period property thing and having bumped along a rocky road with these types of buildings, I've found the road is paved with a lot of snake oil and its salesmen. Even some reputable suppliers and designers make things up as they go so buyer beware.

Now you're opening up an even more contentious can of worms, which in todays world are the binary a) uniform temperature, b) temperature variation. In camp a there is the suggestion a la passivhaus/mvhr etc/ fervents that it's the uniformity that matters mosts as clearly that's implicit in the designs In camp b is a growing vocal cadre of building and human 'experts' suggestion that temperature variation is both more natural, more healthy, and more comfortable than uniformity. I think it's a difficult one, made all the more difficult when comfort is so subjective. Ideally we want to know what @Gone West really means by comfort and then in the BH fashion, we can answer by going completely off topic!

Picture please! Like @ProDave says, if it's the flue is expelling fumes into an extension it is IMMEDIATELY DANGEROUS to life - this is was is called a RIDDOR situation and if your builder has left it like this the builder risks getting locked up by the HSE.

You still haven't read the paper have you? You said it was a fact that Lime was breathable, or whatever. The paper quite rightly highlights that the materials behave differently due to their pore structure. As a result, gypsum is both hygroscopic and vapour permeable whilst lime is only vapour permeable. I merely corrected you to highlight the facts are more nuanced and that the term breathable is meaningless. From any perspective of building, you need to select the correct materials for the job. In some instances, due to the behaviour of the materials, it may be better to select one material over another and it's down to the local context. Therefore, clearly lime may be better in some circumstances than gypsum, and in other gypsum will be more preferrable to lime. However, there is also the fact that there are many buildings without a DPC that perform absolutely fine without damp problems so for me it remains the question that the priority is to investigate the excess moisture first and then, if not practicable, take measures that mitigate against the excess moisture. Unfortunately, I get to see many older buildings suffering from damp that have used lime where the lime plaster is also cracking and peeling off the wall due to long term exposure to excess damp, even far up the wall. But then we get back to the issue of layers such as paint, or even wallpaper and the effects they have on the ability of a wall to regulate moisture content. But even in cases where these layers do not contribute, it has been shown that it still takes years for walls to shed excess moisture following remedial works and if there is a continuous supply of moisture the dampness will remain. The only way a wall will be drier is if you remove the supply of moisture and provide it with adequate time to dry out. This is one of the reasons why @SteamyTea 's point about numbers and measures is so important because otherwise you end up going round in circles in conversations because the reference points are unclear and ambiguous, not really helping anybody - what are we referring to specifically here when we speak of a damp wall? How damp?

Or any self-respecting heating engineer. 😉 And agree completely with the rest 😊

I think it's worth a visit. I attended a self-build project management course there before starting my build and stayed at the centre. We also had the time to walk around the whole site and get a proper lowdown of all the experimental builds they've done, including all the pros, cons, and the odd disaster of the various builds techniques - but at least they're honest about them. We also got out to the site on a current build out in the countryside somewhere to have look. We had a discussion about the hempcrete with, IIRC, the only major learning point that they got a lot of movement/shrinkage of thus gaps at a few joints which needed to be dealt with. The question is whether this movement was down to the hempcrete or the timber frame as it settled.

Have you visited the Centre for Alternative Technology and the Wise building? Wall mainly insulated with Hempcrete - https://cat.org.uk/info-resources/free-information-service/building/the-wise-building/ If I had the opportunity again I'd seriously consider it for a build myself. I think that might have been me. From the standpoint of that research, then if you want both vapour permeability and moisture buffering, then gypsum would be preferable to Lime, yes, and gypsum plaster would be preferable to plasterboard on the basis of the more dynamic tests conducted as part of the thesis. With that being said, we also have to keep in mind that as per the discussion part of the paper, the behaviour of these materials and the building aren't static. For example the moisture buffering behaviour of gypsum (with micro-pore structure) increased in variable temperature scenarios but sinusoidal RH variations reduced the moisture buffering behaviour of all materials. The whole research provides some very interesting data, but also throws up alot of questions, particularly about the overall behavour in real world scenarios of indoor and outdoor environments. To me what is interesting is that the concrete wall performed almost as well as the woodfibre in buffering moisture.

This is exactly mine and @SteamyTea 's point - the term 'breathable' is actually completely meaningless and shouldn't really be used at all. But with respect to the facts about gypsum v lime you should read the paper I linked but the TL;DR is: But the fundamental problem you're talking about hasn't really got anything to do with lime or gypsum, it's down to excess moisture. Excess moisture isn't good for any structure, so deal with the moisture.

Don't forget that flow rates change the resistance within the circuit: If you double the flow rate this quadruples flow resistance and requires eight times the power.

This study is quite a good one where they've built some real buildings at Bath Uni https://purehost.bath.ac.uk/ws/portalfiles/portal/218688237/PhD_Thesis_Cascione_compressed.pdf

Yes, this is key. The complete buildup of a multi-layered wall is also critical - you have a nicely designed breathable wall and then someone goes and applies an acrylic based paint, or uses a bonding coat of something - suddenly the whole thing has become a plastic bag and the main material gets the blame. It's one of the reasons I think people incorrectly think gypsum plaster, for example, isn't breathable and it gets a bad name.

At least I'm not alone

Do I half know both of those. I bought a massive load of bolts for fixing timber plates etc. to the steels and doubling/trebbling joists. When they arrived, I went to put them on a shelf in the garage only to find a few boxes already there full of bolts. I'd looked as hard as I could to find what I had before ordering more as I was sure I had them but couldn't find them at the time! Now my head is even worse.....which is why I come here to hide and get some therapy

With this? https://www.screwfix.com/p/mcalpine-boss-connector-white-22mm/719hr Alternatively you could use an adapter like this: https://mcalpineplumbing.com/traps/condensate-traps-and-fittings/r16-blc-reducer-abs to then fit to a normal boss?

Unfortunately a lot of people are being caught out by this. My dad had this problem while selling a house and it proved futile to try to argue with buyers mortgage lender. In his situation he just had to stump up the money to have the stuff removed and re-insulated with something else. I haven't really kept up to date with what is happening in the market more recently with this so maybe a wider Google might help?

Is the boiler cycling? No Is the boiler showing a low flow situation - e.g. rapid flow temp rise/low return temp? No Is the boiler showing a low differential temp? No - with rads rebalanced but not quite there it's at about 14C which is pretty good Were/Are all the radiator getting hot? No Does the pump selector setting just apply to flow rate? No, it also applies to the overall pressure drop across the system. So the process of commissioning a system is to balance the boiler flow and return and adjust the pump for adequate flow. If you read the whole thread, you'll find it's not too far out and the answer is a pragmatic one. If I was going to be picky I'd say junk the constant speed pump because that should not have been installed on a system with trvs and a pump with proportional pressure settings should be installed instead -cost is hardly any different. But how often do I come across proportional pressure pumps installed and set up on fixed speed? All the bleedin' time and I set them to proportional...

I don't really like to multi-position ones but I have a Little Giant Velocity ladder which is brilliant:

Okay ta, not much you can do with the pump as it stands.

I'm not sure about the efficiency arguments but it's the size of storage tank you need as a minimum in the loft to feed a vented DHW cylinder when it's pumped that's the pain. Sometimes you simply can't fit them in the loft or through the hatch.

On those bedroom losses, you'll be looking at T22 (double panel) at somewhere around 600mm high x 500mm wide mark Delta 30 so if you went 600 x 600 or even bigger, you could reduce your flow temps by a bit

Sorry, throttle back is to close it slightly Your pump should have some lights on it when it is running. Older pumps will just have 3 fixed speed settings, newer pumps can have fixed speed settings and proportional speed setting. Upload a photo of your pump and we can tell you. This can be for several reasons, but often if the rad is hot during the initial balancing followed by not getting hot, there's too much resistance so you might need to open up the LSV on that rad a bit. It's so easy to close the valve a little too much when the system is hot and onlyfind out when it heats up again. Otherwise it can be down to the pump speed setting. Here you're just experiencing the reality of balancing a radiator heating system - it is almost never as straightforward as a lot of articles or videos suggest - so back to requiring the patience of a saint and praying for a bit of luck. Some systems are just a total PIA with the worst ones I've experienced having tall column designer radiators.

Like I said, you've got room to play with as you've got little drop on some radiators and therefore if you spend a bit more time refining the setup, you should see a lower return temp, which is better for effiency. 40C is definitely feasible here.

So you're not far off. As you've got some rads without much drop, I would be throttling back the flow a smidgen there. You'll only need to turn the LSV a small number of degrees, then wait and repeat as necessary. Then test flow/return temps again. With respect to your pump, do you know what setting this is on?