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When we first decided to self-build in 2014, Jan and I visited quite a few passive house builds and talked to various experts; we soon decided that a low energy approach was broadly the way to go for our build. One of these experts, a passive-house evangelist called Seamus O'Loughlin, emphasised that a conventional heating approach (where boiler demand is based on some central thermostat set point) doesn't work well in a passive house, because the time constants of a high-thermal capacity low energy house are a couple of orders of magnitude longer than those anticipated by conventional CH control systems. At the time this seemed a controversial assertion, but because I have done some mathematical modelling professionally, I was able to and decided to do some time-dependent heat-flow modelling and control strategy simulation of how our designed house would behave and this very much supported this assertion. I have already covered a lot of detail of my CH approach in previous posts and discussions, but it’s probably worth summarising some key headlines to set the context for my changes to our heating strategy: We were cash-flow limited during the build phase, so had to make various cost-benefit trade-offs on our build, like most members here. I based these on a general net 10-15 year payback, and it was clear that we wouldn’t be able to achieve a true zero-input passive house largely because of design compromises owing to planning restrictions and our plot size and orientation. However, we would be able to build a low-energy house that would need generally low levels of supplemental heating for maybe 6 months a year, with overall heat losses an order of magnitude less than a conventional build, and the thermal capacity of the heated fabric be many factors more. We decided to go all electric in the house with wet UFH embedded in the ground floor slab only. Cost benefit trade-offs didn’t even support installing an ASHP, though I did future proof the installation to simply the later addition of one if the cost numbers changed. I decided to adopt a simple but unconventional strategy for heating the house: calculate the total heating requirement for the coming day daily at midnight; this is based on actual averages for energy use, average house temperature and forecast average external temperature for the coming 24 hrs. This allows me to dump as much of this heat into the house fabric as practical at the cheapest electricity rate, and for us this is in the 7 hour overnight off-peak window on our E7 tariff. We used to get some spill-over into peak rate top-up in the coldest months, but a year ago I added an oil-filled electric radiator on my 1st floor landing, and one in my son’s 2nd floor bedsit controlled by my Home Automation System, with these scheduled to come on in the overnight E7 window to dump extra heat in the upper floors. This simple addition reduced the thermal layering from ground to second floor, and almost eliminated the need for daytime slab top-up. In practice we have roughly a 1°C daily ripple on overall winter house temperature. Because using a daily forecast computation does have some intrinsic prediction error, this can add typically less than 0.2°C day-to-day ripple on top, but any longer term drift can be corrected by the daily feedback. I have RPi3B running NodeRED attached to some digital thermometers and 4 GPIO controlled solid-state relays (SSRs) to control the time of the UFH pump and Willis heater, plus the 2 × SunAmps for DHW. This was very cheap to implement, and basically has no monthly or annual maintenance. With the current Electricity price hikes, we have decided: To trim our house temperature set-point back from 22.3°C down to 21°C To hard limit automatic heating of the slab to the cheaper 7-hour off-peak window. (We can still do peak by request in one hour chunks if we want to.) To use electric oil-filled radiators overnight to do any additional top-up. I can automate this through my Home Assistant (HA) that runs on a separate RPi4 and do this using MQTT via WiFi connected powered/metered sockets. This strategy currently limits heat into the house to: ~21 kWh through the slab and ~7 kWh through the two radiators. 28 kWh is enough to maintain overall house temperatures so long as the external temperature is at ~7 °C or higher, and it clearly isn’t the case at the time of posting. The house needs about 2½ kWh/K, so with the average daily external temperature at zero today this is 17½ kWh too little to maintain house temperatures. The long term Dec / Jan average where we live is about 4°C, so to maintain temperatures in this case we would need an extra 7½ kWh/day. (This last year, we had 26 days where the average external temperature was 4°C or below and only 2 where temperature was below zero or below.) So what happens when we underheat our house? Simple: it slowly cools down, and very slowly. For example, in the last 5 days of cold-spell, capping the heating has dropped the average house temperature from 22.3 down to 21.3°C, and given an average of -1°C for today, it will be down to our new target of 21°C by tomorrow . At this point I will need to add more heat or to accept that the house temperature will fall further. I will definitely need to add another 7kWh or so extra radiative capacity for overnight topup. We will play it by ear over the next week or so. I can either accept that I will be paying £0.38/kWh for extra peak period top-up during these really cold spells, or let the average temperature fall a little further if we find it comfortable enough (wear a thicker jumper, etc.) This approach works well for us because our house is so insulated and it has a huge amount of thermal capacity within the heated envelope. If we accept a small heating ripple then it really doesn’t matter that much when we heat within the day and so we can time-shift our demand to make use of the best tariff rates: currently over 85% of our electricity use is at the off-peak cheap-rate price. This latest exercise of clamping the heat output to 28 kWh when the maintain level is closer to 40 kWh underlines that the heat budget for and given day can be off by 30% or so and the net temperature drift is still on 0.1 °C or so; the time constants of the system are of the order of a week rather than days or hours. By way of a contrast my daughter lives in a pretty large but conventional 1990s house. When her heating goes off in the evening, the living room temperature drops maybe 4-5°C within an hour.

Looking at the picture again you my wish to add a bit more cavity insulation first in any holes to stop the plaster bridging the cavity. If your really adept you could adjust the inside wall surface position of the opening to fit grill on to that wasn't lop sided...

Mini split A2A conditioning/heat pump? Heat in the winter/cooling in the summer. The controls on them are pretty basic + needs a little more infrastructure work to install than plugging in a heater.

My experience is limited to using a one strike ready-mixed filler over the foam. The filler gives a little so is more resistant to cracking and adheres to foam very well. It's hard to tell how big an area you will be filling from your photo though.

And isn't looking for fame and awards.

https://www.gov.uk/government/collections/find-energy-grants-for-you-home-help-to-heat Might be worth a look.

Like @nod say's, step up the DPC either side of the doors. Some knuckle heads think a door is a wall. It isn't and it's not bothered by rain splashing up unlike masonry.

Except that 0.27 is better than the minimum 0.3. But a long way off 0.18 so there will neeed to be an awful lot in the roof. I wonder who is supervising.

I always put the cavity as being at the rear ventilated level (outside air) because most janky builders leave walls like sieves. If I make that installation level, it drops to 0.254 which puts my calcs either side of yours. The Knauf Insulation was only available in 80mm so that helps them. Couldn't be arsed to find a 75mm batt. Either way @Russell griffiths has to win the pint.

I'm just getting through with 100 mm thermalite, 125 mm beads blown in and 102 mm facework this is on the new regs.

Here's a selection of videos for you to peruse, and maybe kickstart your own ideas. I'm looking forward to making ours -

How about getting a length of 160mm or 110mm drainage pipe (depending on what would fit best in the liner) to come out flush with the finished wall. Then use illbruck fm330 to foam around it. I'd mask the wall first and cut it back when set and skim over. A round or square grille to finish.

You could conduct a small controlled test. Or buy some Borax and recoat it in it. There's an American on youtube (there always is!) who has done masses of construction with aircrete and recycled EPS he collects from furniture stores Made an EPS shredder from an upturned Flymo and a barrel. He uses a leaf vacuum to blow the beads loose into various voids.

We had this problem with one circuit on a new Uponor system. Was simply the actuator for that circuit not clipped on properly - from memory they just clip on, but the clip action is quite hard. The actuator movement is only a few mm, so it doesn’t take much. Take actuator off, check it responds to the thermostat signal, check that the valve moves by poking it with a pencil etc., re-install actuator carefully making sure it is fully clipped on. if actuator doesn’t move with thermostat, check wiring and, as last resort, replace actuator - they’re only £20 or so. You can also swap the actuators from one loop to another as a debugging measure - to prove which actuators / valves work and which don’t. Alan

Once you have a property that is already extended, it becomes very different to do anything elegant that does not require PP. But don’t be put off by the fact you will need PP. Hire a good planning consultant and they can advise you what is realistically achievable.

Is that built under permitted development? (Or whatever applies outside England)

I simply wore one piece coveralls, gloves, mask etc taped at ankles and wrists.

Fees should only amount to a few hundred. Tiled roof will be heavier than sheet metal so structural calcs will need to be redone. Our roof truss supplier did those FOC. Keep in mind the change needs to be considered from an architectural point of view. Due to larger roof structure, eaves and verges could look different. There shouldn’t be any change in SAP, unless the larger roof timbers change your insulation strategy.

Yes. I had a quick look and couldn’t see why the graph was not drawing. I changed the occupancy figures for the hot water tank to something more reasonable (250ltr, 4 persons) and that fixed the dhw requirement being low. I would cross check the heat loss with heatpunk (I know it’s more work, but you need to get this right) and then move on to how you’re going to find a machine that will work for you in your physical location. I know you’re looking into the options for that.

Sounds like you have the flow temp set too high. The floor response is such that you are overshooting the thermostat. How thick is the insulation and screed, what flow temp?

You are right. It doesn’t provide the machine based learning. The free app is generally very comprehensive. You can: - create lots of schedules and easily copy schedules across from one thermostat to another or from one day or day pattern to another - control temperature to the nearest tenth of a degree, both on the schedule and in real time - you can also see how each thermostat behaves when you are home or away - track months worth of temperature and humidity data on each thermostat - and it draws nice graphs for you which in addition to displaying humidity and temperature, also display the local weather and whether or not you had your hot water and/or heating on at the time, so you can see if you can spot any correlation between those factors.

Bars I can't help with, except agree the advice above to get help from a bat expert, not enthusiast. For GCN I can help. I've done maybe 6 or 7 planning apps where newts were likely. In no cases did we do a survey at great expense, or relocate newts (at great expense). Who does the survey, makes the recommendations and then does the work? Yes, so don't go there. We always just accepted that there were newts, which we loved and respected, so no point in catching them. Any expert knows that newts are all in the water at a certain period, so that is when you strip the ground. Sorted. Except some 'experts' may forget to mention that option.

What controller ..? And what actuators ..? Remove the actuator off the misbehaving circuit and see if it’s still warm as it would point to a duff valve

Honestly, if you're planning on living in this for an extended period of time, I'd have a re-think before you go much further. Has this been professionally designed?

Thank you so much, I appreciate the link and advice!

Interestingly our BC wasn’t interested in our results either. It was a tick box exercise. Thankfully he didn’t look at the results too closely as they didn’t add up. I only spotted the error after the event.

Looks great - particularly love the chestnut fencing.

Part 4 of the regulations are the actual how to run a safe project (stable structures, shore excavations etc). So long as that is adhered to then the administrative parts are less of a concern for domestic scale work. Unlikely to be notifiable and any work you do as DIY wouldn't count towards that total. Beware when directing work as you can stray from being a Client into being a Contractor. Especially if overriding a contractor's measures to control health and safety risks. Seek advice if unsure as a bit of money on competent engineering or H&S input could save a larger sum later on.

Yes, I did something similar myself only I did it in a hurry the night before the installers arrived so just rammed the mineral wool into the exposed cavity from inside the loft. Worked a treat. What I must do now is go back and fluff it up a bit as when compressed it loses its insulation properties. I didn't want it to be forced out by the beads under pressure though. While they do use around 100psi at the nozzle it's fairly diffuse when spread around the cavity. Having said that, if there is a gap, it just keeps on coming and coming and coming...

€100/m3 2 yes ago for us inc vat.

75 mil is pretty normal Insulated pb is unusual Weve recently plastered a self build that had specified 100 mil Celotex in a 125 cavity which wasn’t practical to build So he went 75 mil batts in a 125 cavity man’s insulated pb on the inside of the house Expensive mistake on the Architects part

I've lived here for 25 years and never once so much as put a screw into any of these boxes. However, in the extremely unlikely event of me wanting to gain access, I'd get out the garden vac and suck 'em out ready to re-fill. If it's someone else's house, I'd consider it an excellent posthumous practical joke. Do you have any other suggestions for how to retrospectively insulate the voids around these stacks?