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Welcome. Opinions on Potton houses vary. My planning officer actually asked me.. "You're not building another Potton house are you?" Presumably this is because there are two in our small village already and the fake beams on them might have been OK once but just look a bit corny now. It depends what you want as they have a few different styles and some are better than others in my opinion.

If it’s a shared pipe it might be the responsibility of the water company these days - that’s what a letter I had from welsh water a couple of years ago said.

When I first started thinking about my own conversion I did think I'd have the primary frame structure visible internally, in some areas and have an industrial look to the interior, but I couldn't mitigate the thermal bridging, so ended up covering it all up internally and fully insulating it from the inside air, including vapour barrier. The sales man is not wrong saying the roof will be thermally efficient, without cold bridges. Assuming you are looking at Kingspan insulated, profile sheeting (or similar), if you go thick enough it can give decent U values and the marketing suggests decent air tightness is possible. It fully wraps the steel structure so the roof beams and purlins are fully within the thermal envelope. You may have an issue though in the detailing of the roof structure to to the columns. The roof has the steel frame within the thermal envelope, but your description of block walls between the columns and a timber stud structure internally to create a cavity suggests the columns will be outside the thermal envelope in places (although not visible from outside). You have a difficult transition at the point the columns move from being outside the thermal envelope to inside in order to meet the roof portals. Since the columns are not visible from outside, if there's enough room to the cladding (or however you are finishing the outside) perhaps you can wrap the columns to well insulate them from outside air temp. But that doesn't resolve the thermal bridge to the ground. Unfortunately the salesman is incorrect regarding the MVHR. In winter it will help reduce the relative humidity of the internal air, but should help to keep it in the 50%-60% range for comfort. But 21°C air with a 60% relative humidity has a dew point of 12.9°C, so any surface it comes into contact with, below this temperature, risks condensation. To add another worry bead, I also have a concern with the insulated profile sheeting. They are very lightweight, and while they have reasonable U Values (if you go thick enough) the insulation type has a very short decrement delay. I'm not sure how they will perform in a domestic setting. I have no experience of them, so for me it is just a concern, but if you haven't done so already I would try and get the views of someone that has used them in a similar way.

I tested it this morning and everything disappeared through to their side and nothing came back. Whether they are referring to the age or size of the pipe as well I guess I will find out on Monday.

It is odd that both quotes include a transformer upgrade and the price difference is so huge. The advice is to question whatever quote you get.

When their garden starts to fill with your sewage, I am sure they will think about fixing it.

Yup. You could tank a Weetabix and it would be watertight for life. I do go mad with the tanking and sealing up corners / junctions though.

Is than 10 meters distance or 10 meters of pipe run

@SuperJohnG having looked at my paperwork from the TF cit appears company it appears they supplied and fitted the following - 195 x 25mm redwood fascias. 145 x 25mm redwood barge boards 9.5mm OSB eaves tilt boards 9.5mm exterior grade [plywood soffit boards 45 x 45mm soffit bearing timbers T&G lining boards to exposed soffit areas I hope all this helps and makes sense! ?

When the water stops suddenly you get a shockwave going back up the pipe. This can make noises several ways, sometimes at sharp bends or one way valves. There are water hammer arrestors available but Ive never needed one.. https://www.screwfix.com/c/heating-plumbing/hammer-arresters/cat10420003 I believe they are just a pipe with air in acting as a spring (and perhaps a piston/seal to stop the air dissolving in the water?)

The only other possibility is a slow supply of water (like a dripping tap or overflowing loo) down the pipe in freezing conditions, cold enough to freeze the water before it reaches the pipe where it enters warmer ground. For this reason external condensate pipes have to be insulated.

Wouldn’t worry - unless there is a downstream full blockage you won’t fill a stack. Downstairs WCs will be the first to show a problem.

Sorry, have to laugh as I've been catching up with this thread and almost said exactly the same thing starting with 'the elephant in the room' ? But I do agree, it's fundamentally about 1st reducing energy consumption, making homes more energy efficient, and then looking at the appropriate solution for heating and DHW. A while back I read a research paper comparing carbon emissions for passivhaus retrofit upgrade and demolition/new build passivhaus and the conclusion was retrofit favourable (obviously depending on overall context).

Just done this for our build site. I agree, apply direct to the water company, it’s not a difficult process and they will help you through it. I found the guys who came out to survey and inspect the trench were really helpful. They are very used to connecting a standpipe as a part of a request for a house connection at a later date.

The Republic of Ireland had the right idea. They brought forward much stricter building regs and introduced a new standard where all new homes being built from 2020 had to be low energy homes. In order to have gas installed you had to overcome that many hurdles that a heat pump was the preferred option. Oil boilers in New builds will be banned from 2022 and gas 2025. So they are already miles further down the path than the UK are. A standard new build house built by a large developer in the UK isnt going to be suitable for a heat pump as they will have just scraped past the poor building regs we have. In Eire they are suitable. Changing the regs is the only real solution along with actually testing each house performance not just 1 in every 20. To get round the issue of older housing stock if you are doing a renovation then in order to meet the much higher building regs the government will give you a grant to install towards EWI and better Windows and what ever else you want to do.

The benefit of @SteamyTea asking "Apart from capital cost", is that it separates out the issues that get resolved with either carrot (grants) or stick (legislation) incentives from the Government, from the real practical issues. Even in a "high energy loss" home, if you install large enough heat emitters you'll get the flow temperature down so that an ASHP can heat it with reasonable efficiency, you just need a large capacity ASHP. While theoretically possible, in the majority of cases it seems the wrong thing to do when an investment into the fabric of the building would reduce the energy losses, reducing the required emitter size and the ASHP size, so in turn reduce the day-to-day running costs. There appears to be a yet-to-be-announced/legislated plan from the Government that will push to improve the fabric of existing buildings before any ban on the sale of fossil fuel boilers comes in to place. Resolving the issues you mention above will require investment from the home owner, and where the home owner is not able to afford those changes: grants will be required either directly from the Government, or via the energy suppliers and in some cases will be paid for in part by the energy savings that come from those changes. There are practical issues that some properties will have that will make a standard ASHP, UVC, large heat emitter installation difficult to achieve. ASHPs will not be the solution for all. Larger properties that may require a move to a 3 phase supply from single phase, in some cases could make the change to electric heating impractical, however the more widespread requirement for upgrading the transformers to cover the higher capacity required as houses switch to electric heating you'd hope is covered within the infrastructure planning. If the ban on the sale of fossil fuel boilers comes in soon enough, say 2030, then the majority of ff boilers will have reached their end of life before 2050, so few would be forced to change before their reasonable lifespan is up.

Just apply to your water company for a permanent supply to the plot. Obviously you will install a standpipe for use just now.

Would be much simpler just to have a booster pump at the site inlet and do away with the tanks etc. If you only have a ~20m change in elevation, a pump that produces 30m head (3bar) would be enough (assuming effective 0m head at times at the inlet to the site). Individual PRVs can be fitted to units to get pressure below 3bar of needed.

Accepting the danger of appearing like a Dave apologist I feel like some responses to his original post are attacking the messenger rather than dealing with some of the issues. the idea that we can just switch over from gas boilers to ASHPs en masse is deeply problematic. It is the sort of idea that could become government policy without really dealing with some of the issues. Draughty and poorly insulated old housing stock is not an ideal fit for heat pumps. Nor are new builds that scrape through building regs at best and at worst wouldn’t pass if we had a building regulation system fit for purpose. Solutions to these problems are not straightforward but surely they have to include better building standards/regulation and decent incentives for upgrading housing fabric. Clearly we need to make the switch to heat pumps and reduce reliance on fossil fuels but this can only happen if government can think longer term and actually grapple with the issues. The message of reducing energy use rather than just switching to a ‘clean’ energy source needs to be hammered home and built into standards/incentives. Fabric first.

I’d suggest both ..! Use a roofing type membrane stapled to the outer frame before boarding out to cover the insulation and stop anything getting into it, and then a plastic membrane on the inside. It is one place where the foil bubble wrap type products can add a little insulation and vapour control and are easy to install. Just remember to tape the joints.

Loose pipe

Have to admit though, that is some absolutely hideous masonry

How many in the team?

I once had the external waste downpipe freeze and back up into the toilet, was the winter of 86/7. No idea why it backed up in the first place and it thawed the next day and never happened again.

Still no rear lintels or stone sills

The are just hills.....wee tiny things!

No

That is not a new document. I did my own percolation tests, and nobody queried it. Officially HC seem to be pushing the "approved certifier" route but in practice are not bothering to enforce it. I have not used a single approved certifier contractor.

In a well insulated air tight house, there is no risk of condensation because that needs a cold surface to condense onto, and there will be no cold surfaces. Trust me, in a well insulated air tight house with mvhr, condensation is simply something that does not happen.

its not a days job so lets put that aside. To sort it out properly and permantly, ie 15 years, will take a weeks work from a skilled team. anything less than £5k and you wont be getting that.

£10K...wow. I've had a few 3 bed semi's re-rendered with simple s&c and dashed with 6mm clean limestone for under £5k (I guess it depends where in UK you are). As Nod said, it's a few days work on that job you have there and materials cost is virtually nothing using traditional sand and cement. To me, your price sounds expensive. Also, it may be worth asking for other quotes advice to gauge what everyone suggests as solution. As you've found out here, there are a number of approaches to resolving it, with some being better than others. Doing this kind of thing once only is definitely preferable.

Agreed, but it’s a factor in this thread that folk should be aware of.

1/ it's what Loxone Tree runs on 2/ I designed the house for me, not for you, nor your 93 year old mother. The whole point of doing self build is to get your own building that meets your own needs and wants. I believe I can put whatever wires I want in the wall and not have to justify it to the homogenous homes thought police.

You can label those rooms as whatever you want on the planning application. Change of the rooms at a later date would be a building regulations issue (fire escape etc.) and not a planning issue. From a planning point of view there is no change of use of the dwelling/site/property and there is no change to the exterior. Now, if you need to make changes (e.g. new openings or windows) in order to meet the building regs, then yes planning may come into it. Just treat them as bedrooms from the outset so you then don't need to run new fire alarms, change all the doors etc. etc. when you eventually decide you want them as bedrooms.

But also look up how much extra it will cost for an MCS install, work out how much you think you will export, and then work out how long the very low export payment would take ro replay the MCS surcharge. In my case NEVER.

Just remember you can’t get paid export without an MCS registered install.

Planning conditions typically say something like.. "Before occupation..." or "Before work starts on site..." So you only need to discharge the ones that say "Before work starts.." at this stage, however if you are able to discharge the others as well then do as many as you can at the same time because the fee is per application not per condition. In my case I sent them lots of documents and several brick samples as they lost some. Eventually after several email exchanges and revisions to drawings they wrote back saying they were happy so I applied to have to conditions discharged and sent the fee. These days they may want the fee up front with the request to discharge all on one package. Just a reminder: If the CIL is a thing in your area remember to get the exemption paperwork done and confirmed by the council before starting work. Some people have been caught out.. They asked the council if they were exempt and the council said "yes the project will be exempt"....but that's not the same thing as actually applying for the exemption on the proper forms and getting the reply back, you still have to do that.

I ran cat6a everywhere (including to every light switch, motion sensor, TV point, extra wall jacks in each room). no issues with bending or breaking, definitely a little more tricky to terminate but fine with the right parts. My only regret is not running more! (For some reason, only 2x drops to each TV, 4 would have been much better. Largely as I'm now using HDbaseT HDMI repeaters which has stolen one straight off)

@SuperJohnG the set up in your photos appear to be just like the set up we have on our roof / dormers. Ours is a Scottish build and have had no issues with it at all.

+1 for natural wood, I got a sample of the aluminium vulcan board tbh I was a wee bit disappointed.

It is any pre comencement conditions you need to satisfy. Once I had dealt with each I requested confirmation that they were discharged, BC sent me an email followed by a letter stating all pre comencement conditions were satisfied and I may start work.

Definitely Cat 6, if not 6a. I work in IT and did my house in 6a and also ran 6a to garages and shed. No regrets! ?

You can get very shallow led down lights

Don't just run the wire past where the lights are going to be. It's better to form a loop of wire as it makes ita lot easier to work on later if there are any problems.. __0_______0________0______

Excellent summary of the situation Ian. So by 2035 any home not economically able to achieve an EPC C becomes a building plot? Whole estates of them could be demolished and rebuilt? The 21st Century "slum clearances"? It has certainly hardened my view that I would not personally buy a house now worse than EPC C unless it was very cheap with a clear way of upgrading it.

I don't personally see a route to the use of hydrogen for domestic heating, in the "net-zero by 2050" time frame, for anything other than a very small percentage of homes for which electric heating won't be achievable. There isn't a process identified today that can produce net zero hydrogen at anything close to the per kWh cost of either Natural Gas or Electricity. Since the plans to achieve Net-zero by 2050 are taking shape now and legislation is being put in place now, it can't be based on the hope of a scientific break through that opens the door to cheap and plentiful net-zero hydrogen. If and when that break-through does come, then at the point it can be scaled up, maybe it will become a competing option to electric heating. Unfortunately there is no date for when that may happen, but there are significant vested interests in the owners of the natural gas infrastructure that have motivation to talk up the possibility. For new build homes the government needs to make only relatively minor changes to building regulation legislation, for heat pumps to be cost competitive with Natural Gas. It looks like that will be in place for 2025, at which point fossil fuel boilers will be banned for new builds. With the promise from the government that the transition to net-zero domestic heating will be cost neutral in regards day-to-day costs, there will undoubtedly be grants required to improve the energy losses and ready the heating systems of some houses to facilitate the use of a net-zero heating source. For much of the existing housing stock, that will be achieved in the main by legislation, rather than grants. Minimum EPC C certificates will be required for all social and privately owned rental homes by 2028, and by 2035 any home sold will be required to be EPC C or better. I assume by then fossil fuel boilers will not be allowed to be sold. I'd imagine some level of grant will be required for the switch over to a low temp heating system ie. to contribute to the costs of water cylinders and larger radiators and their plumbing. This will devalue the homes that are difficult to improve to the required levels and shift them into the ownership of those least able to afford their improvement. I assume that is when the government has to step in with larger grants to improve the fabric as well as the heating system. My personal experience is that I came to installing an ASHP for my space heating and hot water for reasons other than saving the planet. Quite simply there isn't a gas main with a mile of my entrance, so an ASHP with RHI contribution was significantly better value than the Oil or LPG options I had. I was surprised at how generous the RHI grant was, but it has been tightened since. I shared the common view on this Forum of 4 or 5 years ago, that if Gas was available then it was the cost effective choice. However the mood-music has changed now, or perhaps it's just got louder. My view now is that ASHPs are the right choice for new builds (and significant renovations) even when Gas is available, otherwise within 10-15 years the property will be requiring a significant update or be facing a devaluation. Anyhow, having chosen to go with an ASHP I felt it best to combine it with a low energy loss fabric achieved with U values of 0.10W/m²K to 0.11W/m²K for floor, walls and roof; 0.6W/m²K to 0.8W/m²K for windows and doors and an air tightness targeted at 0.6AH, but to my surprise substantially improved on. I don't know that my experience can really be carried across to owners of existing houses considering moving to an ASHP, but with a heating system designed for the property's energy losses and hot water requirements, it does exactly what it's supposed to, without any fuss and day-to-day running costs that are slightly below an equivalent Natural Gas system.

The No 1 thing to create a "carbon neutral" home is insulation and air tightness to keep the energy requirements down. Then a low power heat pump will be all you need, and throw in some solar PV that will over the year generate more electricity than your house uses to run the heat pump, and you have a carbon neutral house. That is easy to do for a new build (but still a lot of new builds don't come anywhere close). The real problem, is what to do with the huge number of poorly insulated and draughty old houses? Just sticking a heat pump in won't solve the problem. I look forward to reading that chapter in your book.

If you have a leak that needle will drop like a stone, it will literally flop straight around to zero. To give yourself a reality check, crack a valve open the tiniest bit, you will see an instant drop.

It does seem unfair that the Council can continue to collect rates until the Council determines a planning grant. What incentive do they have to hurry? I think a nice letter to your MP might be in order. Ask him to urge the Council to use any discretionary powers they have to grant an exemption for flood damaged properties that need to be demolished because repair is not economically viable.