Temp

Check that. The picture here says "6. Manual Return Valves" https://www.wundagroup.com/wp-content/uploads/2019/10/M07-generic-Wunda-premium-Manifold-25-4-2018.pdf

Appears metal open web rafters are similar to solid wood.. http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16357

I'm pretty sure open web joists would have better thermal properties than solid (eg less thermal bridging). I'm sure the makers would answer that question asked on its own. Might even be on their Web site somewhere. So perhaps see if the calculation for solid timber rafters is OK and add a comment that open web will be better.

Do you know what U-Value was specified for the roof? What U-Value would be needed to meet the Building Regulations? I assume the insulation between the rafters behind plasterboard rather than on the floor of the loft, so not easy to top up.

If you plan to plant any trees put those on a landscape plan and you can reclaim the VAT. Can't reclaim VAT on a shed or greenhouse. Can for a garage if built same time as house. Not sure about a garden office or similar outbuilding, probably. Aside: Since you are at this stage.. After getting PP, If the CIL is a thing in your area make sure you claim the exemption and get confirmation using the right forms before you do any work on site. You must do this even if the planners send you a letter or email telling you it will be exempt. They mean it will be exempt if you claim the exemption on the right forms. Mistakes can be expensive.

I think we used CW1326 cable with at least 2 pairs (eg 4 wires). We ran ours direct in the ground but I probably should have used a duct. We left a coil at the bottom of the pole long enough to reach the top with 5m spare for luck. My electricity meter box is on the outside wall of my office with the CU in a walk in cupboard in the office. So we ran the BT cable into my meter cabinet then into the office following much the same route as the meter tails. Not sure if its a good idea but works for us. The office cupboard has our BT master socket, modem, 16 port hub, DECT phone base station, burglar alarm, TV distribution amp and more in it. I think there is an (optional?) Building Regs Approved Document showing how its meant to go into the house via a duct.

I don't know about using Routers as WiFi Access Points. I guess they would work. Perhaps need to turn off DHCP so devices get an IP from your main router managing the guest network? You can get WiFi access points for £20 - £40 on Amazon but I've not used them. Perhaps others here have. Example: TP-Link TL-WA901N 450 Mbps Wireless N Access Point, Passive PoE Power Injector, 10/100M Ethernet Port.. £20.49. https://www.amazon.co.uk/TP-Link-TL-WA901N-Wireless-Injector-Ethernet/dp/B087MSF7BR/ref=sr_1_1?adgrpid=53310796295&gclid=CjwKCAjw4c-ZBhAEEiwAZ105RSuejHOnZC2FA83urbj3nXcfmYXfnfcfR19_iwfBGee8GOj2YL9PxxoCn9oQAvD_BwE&hvadid=259016914938&hvdev=t&hvlocphy=1006818&hvnetw=g&hvqmt=e&hvrand=10865873223415071343&hvtargid=kwd-361530570237&hydadcr=5058_1827822&keywords=wifi+access+point&qid=1664402731&qu=eyJxc2MiOiI0Ljk3IiwicXNhIjoiNC40MCIsInFzcCI6IjQuMTMifQ%3D%3D&refinements=p_36%3A-3000&rnid=428432031&sr=8-1

HMRC see it like this... Fitting is labor which must be zero rated to you. If you purchase worktop from B&Q it would be standard rated to you but you can reclaim it after completion. Mixed labor and materials (eg supply and fit) should all be charged to you at the same lowest rate. In this case that woukd be the zero rate for labour. So in short, it should all be zero rated to you. If you are given a quote for £xyz plus or Inc VAT its best to get it amended before you accept it.

Oh yes, I didn't notice that.

Is the amenity block just a loo or do you want WiFi in or near there as well? If just a loo I would buy a cheap hub to put in there. Approx £10. If you want WiFI in the amenity block then many WiFi access points have a few wired connections as well. So you can use a WiFi AP as a hub. Having the same kit everywhere means you can set up one, save the configuration file and upload it into the others. All the menus are the same etc. Create the guest network at the house/static van end so you avoid having to go to the amenity block to reset it?

If I was building it myself I'd go for solid blocks so I can use a jig like this then fit internal wall insulation. https://youtu.be/-mciVlgZz5g

Think you install the liner and register plate at the bottom then fill the space around it with Vermiculite... https://youtu.be/Kk6Et89GOCg Are you saying the chimney has been removed in the loft so the bare liner would be exposed?

If you fancy a weekend away I suggest the Batibouw Trade show in Brussels 14-19 March 23. We went in 2005 and there were 13 halls in different categories. The Belgians take house plans so they can get quotes or place orders. Caution: Some days are normally trade only so check the website. Take comfortable shoes because if you want to see the whole show its quite a bit of walking.

Many councils have an SPD with a wide variety of names like "Seperation of Dwellings SPD" or "Separation Distances and Amenity SPD". Find out if your council has one and check if you comply.

RCD work by comparing the Live and Neutral currents. If there is a difference they trip because that implies a "leak" somewhere. Eg Where did the electricity go if it didn't return via the neutral? You could use a similar idea to detect central heating leaks. If the boiler flow and return aren't the same there must be a leak. A common problem occurs when two circuits have their neutrals connected together so the current from the live of one RCD can return to the neutral of another. Sometimes the problem only shows up when a high current load is switched on or off.

I should add that although we found our builder by driving around he still had to out bid the others that quoted. When you get quotes don't rush to accept the cheapest. Its important to check they have all quoted for the same thing. One may have allowed less for the kitchen or nothing for your driveway and fencing. It took quite a while and many questions to make the quotes we had comparable. If you plan to provide a lot of second fix items make sure they include for fitting if you expect them to do that. Some people prefer to hire their own trades for that. You could ask builders if they use a tame Quantity Surveyor to do detailed quotes or just the back of an envelope.

Plus 2. We found our builder by driving around looking for building sites with nice houses. When I told them I was going to need a builder they all hapilly showed me around. Nothing like an unannounced inspection for getting a good idea what they are like. One or two sites were horror stories. Look for attention to details like air tightness, neat plumbing or evidence they are protecting wood flooring or stair cases. Try and ask a few questions. Had a few tell me "You dont need to worry about that we take care of it". Others took time to explain or show me how they were doing it on the house they were working on.

I was thinking you could run three core & earth to each PIR. So you have power to the PIR and switched live coming back to a box in the house. Then run switched live to the light(s) from there. Put the relay or onto isolators in another box in the house. I 3D printed a box for the Arduino with a wall for isolation but it could do with improving.

I'd be wary about fixing to the coping. I'd be concerned about the coping coming unstuck off the top of the wall. Better fix into the wall itself if possible.

Never seen that type before but I'd try looking in the hole in that last photo to see if there is a screw or Allen key screw in there that releases the cover or even the whole door. Take care, I'd want help to support the door before undoing anything and put packing under the door to take the weight.

I used one of these to interface mains to an Arduino. It's used to detect when my boiler pump is running. https://www.ebay.co.uk/itm/-1-Channel-Bit-AC-220V-Optocoupler-Isolation-Module-Board-Adaptive-For-PLC-/154400482521?pageci=204718bc-c2f2-4557-a2dd-49ea4e2a55af&redirect=mobile

I think I would ask the planners for a copy of your 1978 planning grant and check PDR we're definitly removed. Probably we're if they say so but still check. I would also consider making a planning application for the same thing as your prior approval/permitted development application. It might be they only revoked it because you don't have PDR not because of other planning reasons. In addition speak to a planning consultant/lawyer about them revoking your permission as I don't think they can do that if the original approval was granted in error. See my post above. It might be the way to proceed would be to file an application for a Certificate of Lawfulness based on the revoked planning approval and citing that they cannot revoke it on the basis of an error. But this is definitly one for an expert to advise on before you do anything.

Is it causing a problem? I think my trap is even shallower. If the stack is open vented, and nothing else connects into the pipe between the bath and the stack then I think it will probably be fine. I think digging the floor out for the trap is OK as well. You could raise the bath on a plinth but that doesn't always look great.

+1 It's easy to find people on the Internet complaining about extractor fans on neighbours wall pointing in their direction. Avoid if at all possible. I don't think there is anything in the building regs regarding the location of extractor fans (but there is a 600mm seperation for boiler flues in Part J). The only thing I can think of is that regular cooking smells might be considered a statutory nuisance.

I think I would ask a planning consultant about this. https://www.no5.com/media/publications/what-do-you-do-when-youve-been-granted-planning-permission-by-administrative-error/