IanR

No, PD only covers use incidental to the main dwelling, which means the building can not be capable of being an independent living space. Normally, the Council will act on a complaint and then give the owner a chance to normalise the situation by submitting retrospective planning. If the planning then fails the building would need to be modified to something acceptable (or meets PD), or removed.

But, a house that has uncontrolled (natural) ventilation above 3m³/m².h@50Pa is deemed to have sufficient ventilation (when combined with trickle vents and wet room extractors). That leakage is unfiltered and without an option to recover energy from. Any additional ventilation brought in by an MVHR system is unrequired, so while it may be filtered and have 85% of the energy recovered from it, it is additional, unrequired ventilation and therefore adds to the energy losses and dust/pollen/pollutants (that make it through the filters) within the house. It's having better air tightness that stops the uncontrolled leakage of warm air and ingress of dust/pollen etc. and then provides the option of heat recovery and filtration.

MVHR doesn't bring benefit in itself, but it facilitates air tightness better than 3m³/m².h@50Pa. Good air tightness brings comfort and energy cost benefits and allows you to then filter the required ventilation to remove duct and pollen. For air tightness greater than 3m³/m².h@50Pa you must have whole house mechanical ventilation.

Muckaway should be less for a raft. Depends. There's no reason for it to be more expensive, in fact it should be cheaper when you compare like-for-like, including performance and include the screed you need on a traditional foundation but don't require on a raft. However, insulated rafts remain niche in the UK and you need to do your own ground works (or hire your own team) otherwise you will be paying a premium for labour, concrete, steel etc. from a company that packages it all up for you. A previous discussion:

If you have "Superfast" then I assume you have a temporary location for the Network provider's ONT box, perhaps on the mobile home side, or a kiosk. If that's the case you need to contact your ISP and ask for an "ONT shift". This is chargeable, so they should arrange for the Network Provider (OpenReach etc.) to come and survey and quote them for the work, which the ISP should then advise you the cost of. You may not get much detail of the works to be completed, but a cost from the ISP for an ONT shift, will confirm to BC that the new poperty will have FTTP. BC are then also asking for you for a schematic that high-lights the ONT position in the new property, they'll want to see provision for any ducting required to get to that position, a power outlet in the close viscinity and your network distribution (Router and Switch) close by.

Bring down the lower edge of the cladding to the top of the ground floor windows, so you can put the top boxes for the ground floor blinds behind the cladding also: +1 for external blinds with automated shading control.

I'm not sure what you mean by "infiltration tunnels" is it a specific product? However, it's not a Council decision, it's a National requirement. If you are going to have a private sewage system in England then you as the operator have to either meet the General Binding Rules or get a permit from the EA. Building Control should require you to do one or the other as per your local council. As the "Operator" of an STP without a permit, you are criminally liable for the STP meeting the GBR's. The wording as been softened in the 2023 version of GBR's to now say they will only bring a criminal prosecution if your STP causes pollution AND you do not meet the GBR's. If the "infiltration tunnels" can be used to construct a drainage field and meet BS 6297:2007, there should be no problem. Edited to add a relevant previous post:

It's not unfortunately, in codifying the requirement natural options have disappeared for perforated tubes with their fixed cross-section and calculable flow-rates, so something more like Still relatively simple, but a second chamber is required for an STP, the first being a settlement chamber to seperate the solids (that needs emptying every 1 - 2 years), then the aerated liquid chamber with a filter media.

That's a misunderstanding. While the discharge has low toxicity, if it is allowed to build up it can get to a hazardous level, so the GBR's require their discharge to be controlled either into a drainage field or a water course.

Then to meet the General Bing Rules you'll need a Drainage Field that meets BS 6297:2007 I'm not sure if that document is available free of Charge, but if you ask Gemini, it gives you a good idea of what is required: Edited to add what looks like a good reference to clear up any confusion on what a Drainage Field is: https://www.homeseptic.co.uk/drainage-field-size-calculation-and-design/

If your site is in England you must meet the General Binding Rules, otherwise you require a permit from the Environmental Agency. The GBR is the far easier route. For a new discharge you can not use a soakaway, for discharges to ground it must be via a drainage field. Both STP and Drainage filed must be in line with the relevant British Standard. See Rule 9 for the specifics Ref. https://www.gov.uk/guidance/general-binding-rules-small-sewage-discharge-to-the-ground Lots of rules, make sure you meet all of them. Under the GBR you can discharge to a Water Course in some circumstances, so when you say "cannot discharge to a water course" I assume you mean you do not have access to a suitable water course.

Essex Highways require gates to be a minimum 6m from the highway to avoid a vehicle stopping on the highway in order to open the gates. Footpaths are part of the highway.

100mm PIR would bring the 9" solid brick wall down to 0.25 U Value from around 1.9 The ubakus site allows you to try different build ups, although uses German products. https://www.ubakus.de/ Of more a concern through would be ensuring moisture can get out of the wall. How old are the walls? Is there a damp proof course?

For some PU resins, voc's would be released during the curing process, once cured there is no further off-gassing whether or not heat is applied. That statement doesn't cover all PU foams where a foaming agent is used. Good ventilation is recommended during the 5 days of curing. There are also low-voc and zero-voc options that reduce off-gassing during the curing phase. Wouldn't that be epoxy based for cement repairs, or are you referring to a PU sealant to fill cracks? Epoxy resins do continue to off-gas after curing, although at a much lower rate than during curing.

Who's deciding the definition of "self-build"? Gemini's definition:

That's a complete misunderstanding of the product.

Hi and Welcome. SIPs = don't do it, go for a twin wall or I Joist structure and cellulose blown insulation MVHR = great benefits, but only if combined with a < 1.5m³/m².h @ 50Pa infiltration rate. UFH = no regrets Best Flooring = Hmm, subjective one, but combined with UFH I'd suggest PU poured Resin. Good Luck!

"DWG" is the native format to Autocad, so if the house plans were authored in Autocad the DWG may include templates, macros, metadata etc. that the Architect feels is their intellectural property and may not wish to hand that information over. But, DWG can also be a neutral file format exported from other CAD systems and contain only the Vector image of the house plans that you see when you print them out. Depending on what "he" intends to do with them, a vector PDF will/can provide the same info as a neutral file DWG.

No harm in requesting, but likely the best you can expect is a vector based PDF. Some architect's seem to get prickly about handing over their native CAD files, unless you have agreed it prior. This is defintely one to agree up front. "CAD" means different things to different people, what are you hoping to do with the file(s), a vector PDF may well be sufficient.

If it's confirmed you have PD Rights then it should be OK, however at 40m² it could be getting to a scale where it being "incidental to the enjoyment of the dwellinghouse" could be called into question, depending on its intended Use and the size and occupancy of the dwellinghouse. It may be worth submitting for a Certificate of Lawful Development if there's any doubt on its Use being "incidental".

Energy perfomance targets. To meet current building regs you need to achieve < 8m³/m².h @ 50Pa Air Infiltration (leakiness), however to meet PH Spec you need to achieve 0.6 ACH @ 50 Pa. Air Changes per Hour is a different unit for measuring Air Infiltration and there's no set conversion figure that works for all houses to convert between the two, but very roughly 0.6ACH will be in the order of 1m³/m².h. So, a PH spec house roughly leaks 1/8th of the air volume of a house that just meets Building Regs. The difference in construction, between the two is certainly attention to detail, likely the use of tapes and foams, and maybe the use of air tight barriers. Some construction methods and insulation types are easier to get air tight than others. Celotex in your roof needs mitigating with taping and likely an air-tight barrier and depending on your wall costruction, other mitigation may be required. Take some time to consider this for your build. MVHR doesn't bring you any benfits in itself, it's the air-tightness it facillitates that brings the benefits. If you are not targetting < 3m³/m².h @ 50Pa air infiltration rate, you have no need for whole house mechanical ventilation and adding MVHR will increase your energy losses, rather than reduce them, while costing you to power and maintain the system. Achieving <3m³/m².h @ 50Pa will take a conserted effort in both design and construction, it doesn't happen by accident. If you plan to put the effort in to, say, target 1.5m³/m².h @ 50Pa or better, then you really will benefit from the air-tightness and MVHR with both a more comfortable home as well as lower heating bills, but if air-tightness is not your focus then MVHR is an unrequired expense.

The RSJs are likely painted (and appear to be so in your image), and there's a likely gap between them and the Aluminium, so no chance of galvanic corrosion. The fixings will have a very small contact area, and you're unlikely to us an un-coated steel screw, as it will corrode anyway, so a coated screw (zinc passivate for instance) will stop any galvanic corrosion. If it was galvanic corrosion it would be the aluminium corroding - as its the stainless, the spec of the stainless just isn't up to the environment.

When you order your new service, from an ISP, they'll liaise with OpenReach to make the connection to the house. Should be free of charge if they deem the cost to be below the £2K threshold. OR will install via existing ducting, even without a chord, but they are limited to their 75m "rods". Ideally use the standard ducting that OR will supply FOC, to avoid a jobsworth saying they can't install in your duct. You need to contact OR for this, and register as a developer. Standard install terminates to the outside of the house and drills through to put the ONT on the wall the other side, where they expect you to provide a power socket. I had no issue talking them into pulling it into the centre of my house and up to the 1st floor where my Node 0 is, but that's not a standard install. If the ducting goes under the slab and up through the floor, they don't really have an option. The only caveat though for your situation is you say the previous property already had a connection. Will the new property be the same address? That may change how OR look at your connection. The computer may even say "no" initially, where you are recorded as having a connection and the ISP just needs to send you their router. If you can, get OR out for a site survey, by registering as a developer, that may help their records record you as a new connection.

Yeah, I understood that from the 3D, looks like x3 230mm wide strips of 150mm thick XPS. That looks tricky to keep in place during the pour, or is another set of timber formers going to be constructed to back it all up. Your Engineer doesn't appear to have made it easy for you, or perhaps there's some benefit that's not immediately apparent.

Ah, OK, Inner upstand not built yet - be interesting to see how you build that up and support it. You could have done the outer ring beam with formers too, to save all that timber work.