ProDave

If it is any consolation, I was disappointed my air test came in at 1.4, though the tester was having kittens saying it was the best one he had yet tested. The building still performs very well, heating usage is exactly in line with what the heat loss calculation says it should be. There are no noticeable draughts and it fits my basic test that on a windy day you can open 1 window or 1 door with no perceivable draught entering or leaving that one open door or window. (previous house with all the plethora of individual extract fans, window trickle vents, cat flat, letter box etc, if you did that there would be a draught blow through and likely an internal door blow open or shut) So although it would have been a "fail" that does not mean it is a bad building and was a waste of time trying or it is going to waste a lot of energy. The flaw in your argument is if you knock down and rebuild you would just employ a specialist to do it all properly. I only know of one timber frame company that will erect a complete frame and guarantee a particular air tightness figure. And that is for the bare shell. You then have to guarantee that all your following trades, plumbers, electricians, even joiners, do not drill holes in your air tightness layer and destroy your good air test. It is a sad reflection on the UK building trade that most tradesmen in the industry don't have a clue about air tightness and think you are being silly when you talk about things like that. You really are best seeing to the detail yourself, you have done a large part of the house already, just carry on. With a rebuild I bet you would either still be doing the detail yourself, or complaining that it has been done wrong and having that same argument.

Picture zoomed further out to give context and one from inside showing lintels above the door and window? Are the lintels where the wall steps out? The house wall steps out, how is that supported or is that external wall insulation fitted that makes it step out? What are you hoping to achieve? It looks fine to me as it is as a useful outside / work / storage space. What to you need or want to get into it that requires a larger door opening?

In the 4 1/2 years, the total export (i.e. wasted) is standing at 334kWh (I have fitted my own export meter) Export happens when generation exceeds what the immersion heater can consume and nothing else in the house is using power. For a lot of the year I also dump to a small convection heater that is turned on when that situation arrises, but in the summer that is disconnected (though I could out of spite just move it to the garage) More export happens on the occasions when the immersion heater thermostat has cut out when the tank reaches maximum capacity. If I was able to get paid for the export at the silly low 5p per kWh that would only have earned £16.70 If I had a smart meter and signed up to one of the more lucrative export payment deals, that might have earned perhaps £50 in export. But any export payment would require it to have been an MCS install. Clearly the extra of an MCS install vs DIY would NEVER repay itself in export payments. If I add more PV that will be with battery storage, that is another topic for the future, I have to build the car port first where it will likely be mounted.

Can planners insert ownership clauses? e.g the annex may not be sold as a separate unit to the main house? I ask because near us there was a small cottage on a very large plot. the owner got permission for a new, very much larger house in the grounds in addition to the cottage. There is a clause that the plot title cannot be split. The present owner lives in the big house and lets the small cottage as a holiday let.

An update and a milestone. Each week I log all my meter readings, import usage, PV generation, ASHP consumption etc. Today, entering the figures into my spreadsheet revealed that I have self used £1499.79 worth of electricity since installing the PV. That has taken 4 years and 16 weeks to achieve that. It's all free now baring equipment breakdowns, That is shorter than the initial estimate of 6 years, due to the higher cost of electricity now. If electricity had been as high as it is now right from the start, payback would have been just 2 1/2 years. Starting to think of an addition to the system now.........

It will be the inverter capacity that limits how much of your stored energy can be used. Will your proposed PV and battery system be able to supply 14kW? If not it will never all be provided by "free" electricity.

An annex, is expected to share some functions with the main house, so perhaps limited kitchen or bathroom functions to the occupants use those in the main house. The one near you turned down probably had all that is needed to live completely independant to the main house and the planners thought it was a separate dwelling in all but name. What are you expecting from your annexe?

To be any use, an instant heater has to be at least 10KW and that will only give you a mediocre shower flow compared to an UVC. The chance of getting much "free" electricity from that with your solar PV is slim. You would be doing all your showering and washing at about mid day to get maximum sun. An UVC with a diverter just sits there with whatever spare PV energy going into the tank, and then just sitting there waiting to be used, day or night. It sounds like an accumulator is what you want for the water supply issue, but be prepared for another cupboard space to be used up by another big tank.

An "electric boiler" can be 2 types, one is a hot water storage tank with a low power heater, and the other is a high power heater with no storage it just heats the water as it passes through. Either will take up some space. So why not make space for a proper unvented hot water cylinder. This can be heated by the ASHP at a COP of at least 2, usually better, halving the energy needed to heat your hot water. And a solar PV diverter can connect to the tanks immersion heater giving you free hot water when the sun is out using up all the surplus PV not being used by something else. Is the water pressure really poor or is the flow rate poor? That is a separate problem to address and an accumulator may be the answer to that one.

If you want to keep the trenches open for a while I would get some cheap but thick shuttering ply, cut it in strips to match the trench depth, line both sides of the trench with it and then lots of timbers side to side cut to be a tight fit, to brace it and keep the sides under pressure. But surely all you want is a bit of paper from BC to say you have "started the development" So ask them for that. If you get that then does it matter if the trenches get filled in?

Think of the logistics of moving out and storing all that stuff you plan to re use, without damaging it. If you have a handy barn, fine, but if you have to rent storage factor in the costs of that, and transport, properly. If you carry on, air tightness seems to be the issue that is concerning you. I assume enerphit has an air tightness requirement like passivehause does? Would it really be a "fail" if you did not meet the air tightness requirement so failed to get enerphit, but still had a warm cheap to run low energy house? There are many on here like myself that just aimed for a low energy house without any certification, the constantly warm house with low heating bills was all we wanted.

I was considering adding extra insulation in my service void. If I had done so, I would have left a gap either side of any cables so they were not "in insulation" I have not found any definition of how wide that gap would need to be.

Rule no 1, when something has changed, ask what has been done. It was dry. You built a wall. It is now wet. could there be a pipe under there not far from the surface, and a fixing (nail or screw?) holding the sole plate for the new wall has penetrated the pipe?

Sounds more like the turf was not bedded onto decent soil or not watered enough and the grass has dried out and died in places. Whatever you do lots or watering needed until it is fully established.

I can confirm the SilikonTop is prone to "dirt". In our case it is mostly the north facing wall, and after about 5 years it was looking grubby, upon closer inspection the "dirt" was mostly green in colour. I concluded it was moss or similar algie growing, and I "cleaned" it by spraying with diluted bleach, diluted about 1 part bleach to 3 parts water and sprayed on with a squirty bottle. Just left it for the next rain to rinse off and the wall is clean again. No abrasion needed. So it looks like this is the "maintenance" needed every few years?

I don't see why a rotary will "stress the grass" Rotary a lot easier to maintain, simple blade to sharpen or replace. And Rotary will cope with long grass and weeds. I once had a cylinder and if you let the grass get too long it just would not cope, and a blunt cylinder is difficult to sharpen and expensive to replace. Our present mower has a plastic deck. I was sceptical the plastic would be strong enough and expected it to crack or split, but it has not. Far better than previous mowers with a steel deck that just rust away long before the motor has worn out.

You should have if the electrician has done it properly. It has been a long time since they became mandatory.

Without a doubt double pole is safer. Why are you looking at sockets with an RCD built in? Your RCD protection should be at the consumer unit, having more than one RCD is not safer, but it becomes pot luck which one trips. So assuming you don't need an RCD because your wiring is already protected by an RCD in the CU and you want DP switching the choice becomes: https://www.screwfix.com/p/british-general-ip66-13a-2-gang-dp-weatherproof-outdoor-switched-socket/67928 £8.99 https://www.screwfix.com/p/knightsbridge-op9n-ip66-13a-2-gang-dp-weatherproof-outdoor-switched-socket/841vf £17.99 https://www.screwfix.com/p/mk-ip66-13a-2-gang-dp-weatherproof-outdoor-switched-socket/98279 £29.99 for me it's the BG. You would have to break that 3 times more often than the MK for the MK to become better value.

I don't know if it is required, I don't have a mortgage and am not intending to sell so I don't have a structural warranty. There was a BBA certificate when the design and drawings was submitted to building control, I don't know if that would have been an issue if there had not been. It was when i was being given the run around by Baumit and their suppliers that it came to light that BBA certificate had been cancelled. They would not answer why, but it was not a good sign that it was cancelled. Baumit won't say why and BBA say they can't say.

For upstairs heating 200mm, 2 pipes between each joist would sound more logical as shown in that photo. Many of us in well insulated air tight houses find no heating upstairs is needed so have not fitted any. You can't notch posijoists so battening after fitting the pipes is about the only way. Just make SURE whoever fits the plasterboard to the ceiling does not put a screw through the pipes. Keep a record of where they are so you don't put a screw through them in later life......

I would be VERY cautious using any Baumit product in the UK. If you search the forum you will find my posts detailing the problems I have had with my own render and the total lack of disinterest from the manufacturer to even come and have a look and suggest what might have been the cause of my problems. When I installed mine, there was a BBA certificate for it. That had been cancelled when I last looked. Do some research and check there is once more a current BBA certificate for the product you are intending to use. If not treat that as a big red flag and look for an alternative product.

We did this (but with wood fibre board not block) We used a render stop bead and that covered the compriband nicely. I found it easier to fit the compriband first. it will start expanding and then squash it with the wood fibre board as it was fitted. Make sure your brickies know to position the blocks so they squash the compriband again.

No problems with any BG outside socket that I have ever fitted including the one on my own house.

Rainwater to a soakaway? Long since silted up? Does it look like it could connect to a downpipe? Of so use a hose to run water down that downpipe.

I am going to try this on my balcony. Rather than use a standard outlet, I am just going to use a single chain, and just drill a hole in the bottom of the gutter such that the chain is a very tight fit into it, and secure it with one link on it's side and probably a shackle as well to be sure it won't drop out.