IanR

Hello & welcome. What planning permission has the Barn got currently? Full planning for a Conversion, Outline planning (which I guess would be for a knock-down and rebuild) or Permitted Development Class Q Change of Use? Each will have different levels of restriction on what you can replace and on whether you can move the walls out a little to get the frame fully within the thermal envelope of the developed building. Assuming it's not OP for a knock-down and rebuild. Have you considered re-submitting planning to do so, using the planning you have as a fall-back? Is it a concrete, portal frame "shed". That's what I'm familiar with from Atcost. It's a lightweight frame, for a lightweight roof and wall cladding (unless the walls are on their own strip foundation), and the columns will typically have small foundation pads that can't take much more than the lightweight structure the portal frame is designed for. All this means you've got some compromises to consider on how you will insulate, and support your new walls and roof. Since it's a modern shed there's unlikely to be much architectural merit that the LPA can argue needs to be saved, and they may well be willing to let you build new, although likely in a similar style. I've completed my own conversion of a steel portal frame (cow) shed, under Class Q, and at the time my LPA wouldn't consider a knock-down and rebuild, although now there is plenty of case-law that they'd struggle to argue against. Mine could have been a far more efficient build had I been able to lose the original portal frame. With regards to next steps...if you have time, I'd not rush in. Consider your options and get a feel for what building methods you'd like to follow and what aspirations you have regarding energy performance and comfort. Once you know what you want, then find the professionals that can help you deliver it. One Caveat though is that if the Barn has Class Q, then you have 3 years from the Approval to complete the conversion, so there may be a time pressure.

2. Someone like: Dr. Rod Williams of Williams Energy Design https://passivehouse-international.org/memberSearchDetails.php?member_id=2349 No overlap with your Architect, Rod would do the thermal modelling and suggest/recommend improvements to you/your Architect. If you have some inherent design issues, say cold bridging at door thresholds, you'll need to decide who re-designs this area, who has the expertise in your chosen build method. 3. Full detail is required unfortunately. There's not a short cut. 4. Then you paying for it twice, and hoping you meet targets with a guestimate.

The Structural surveys completed for planning or paid for by the applicant, who of course is paying for a survey that states the building is capable for conversion. If there's any doubt, I'd suggest you getting your own survey so that you can rely on it. My own LPA is very prescriptive about how much of the original building must remain within the new conversion, and have been known to put a stop notice on a conversion if challenges are met during the build that may change what was stated at the planning stage. What conditions are there on the OP? Brown field sites would normally require a contamination survey prior to commencement. It may get no further than a Stage 1, where there is a desktop search completed and a site walk-over. Has this already been done as part of the planning? If not, it maybe worth getting Stage 1 completed so you know if it highlights any risks that will need to be investigated further. The Stage 2 surveys can cost in the £5K - £10K range, so it's good to know if it needs to be budgeted for, and remedial actions could need a big chuck of budget. Next for me would be assessing the difficulties in getting utilities to the site. Difficult to get costs prior to you owning the site, but if you know your going to have to bring power and fibre 500m across fields, then you need a figure for it in your budget. Have you investigated the option for re-applying for planning to swap to a knock-down and rebuild? The LPA may consider it, unless the building has historic value. Converting agricultural buildings is typically a compromise that will either cost more to complete or perform poorer than an equivalent new build.

It is. But, I'd assume that figure includes the change from gas to ASHP, for the average new build. If the average new build would achieve a SCOP of 2.5, then 40% points of the reduction is coming from the change in heating source. Still leaving a 35% - 40% improvement in building fabric performance, some of which has already been achieved with the 2022 Regs changes.

That seems completely over-Engineered. I know nothing of you build, but assuming it's not more than 2 storey, and you have reasonable ground conditions (>70 kPa/m² bearing capacity), then a very simple 100mm RC Raft with a 300mm Ring Beam should be achievable. Advanced Foundation Technology's standard Eco Raft is as per below and will get you close to PassivHaus performance. Slightly more complicated is their Eco Raft Double L, which is PassivHaus level performance, and can take a heavier super-structure. It would cost you nothing to get a ball-park cost: https://www.advancedfoundationtechnologylimited.co.uk/quick-quote-form/

Interestingly, Oakwrights (where the image in the first post came from), have almost this solution for their PassivHaus option. They just don't include any insulation in the service void, and use Panelvent Sheathing instead of Egger. I have a friend with a beautiful, Oakwirghts' Framed home. It really is lovely. It has been a labour of love for him though to keep up with all the movement of the frame. Every year he goes around filling, caulking and redecorating. He's about 11 or 12 years in now, and it's still moving. At times there have been gaps between the Oak frame and the plasterboard that you could get you hand through. For the PassivHaus option, I assume the Oak Frame is independent from the I-Joist Frame, which seems quite an expensive option. @Alan Ambrose, What's your expectation of the Oak Frame? Will it be a green oak frame and will you be using someone like Oakwrights? Do you want the oak frame to be visible externally, at all? Do you want frame to be structural, or are you happy for it to just appear to be so. To combine a green oak frame with Passivhaus type aspirations is likely to lead to some redundancy, and therefore a higher cost, and maybe some compromises.

Yes, more like that. Maybe still some work to do on I-Joist spacing. 400 centres may reduce the performance a little. No, I'm thinking of the extra timber content that gets included once they actually Engineer the panels for your roof. Assuming the SIPs will be structural, there will be timber sections running the length of the SIPs to help take the load, and these create cold-bridges through the panel. I did have a SIPs structure costed for my own build and my experience was that no one tells you about the performance effect until the last minute. Random picture off the internet to show what I mean. The SIPs roof engineered for my build had quite a bit more timber that shown in the image, but I do have a shallow pitch and 6m spans.

It's breaking the rule of having increasingly vapour open materials towards the cold surface, hence the condensation at the PIR. Unlike your section, SIP on the roof will have a lot more timber structure and therefore "cold bridging" within the SIP, and more condensation than shown, Why not just go with 300mm or 350mm I-Joists, full of cellulose and a fibreboard external layer. Without any cold bridging, it would perform better in practice.

You could possibly get a more "efficient" insulated raft from one of the companies that specialise. A 250mm raft reinforced with 2 layers of mesh sounds over-engineered. What build method are you going with for walls? and are you planning UFH installed within that 250mm? The following is a list of Insulated Raft Suppliers. I had an excellent experience with AFT Ltd. (Advanced Foundation Technology Ltd.) I found a lot of the EPS manufacturers, selling formers for insulated raft foundations, are tied to a particular Raft Supplier, so will only sell their formers via and Engineered package.

Indeed, hence me including However in 2025 that will not deliver anywhere near a 75% - 80% reduction in CO2, and will require "significant uplift in fabric performance as well".

Hopefully tangible details of the 2025 Future Homes Standard will start to emerge soon as the changes are pretty significant, and the industry needs to prepare. Reportedly, homes completed to the 2025 Buildings Regs will produce 75% - 80% less CO2 than the homes built to pre-2022 regs. If that's allowing for homes heated with today's Electricity mix v. Gas, there has to be a significant uplift in fabric performance as well. I'm not sure Architects are ready for it, let alone the volume builders.

I followed the Potton PassivHaus case Study using Kingspan SIPs panels when it was being built 5 - 10 years ago. They were running a blog that was regularly updated. I remember they struggled a bit with the air tightness, failing the first air test they did, and later commenting that an internal membrane was required to get it below the 0.6 ACH target. I thought the blog was quite honest of them. SIPs are considered "airtight" in a standard building regs environment, but the shortfalls need to be mitigated for PassivHaus levels of airtightness.

Once the landline number is ported to VOIP, it's no longer "attached" to a residential address. While it will work on a VOIP handset, connected to the house network, it will also work on any mobile phone that's connected to mobile data. Keeping the old landline number, that others are familiar with and for others identifying a location, is just convenient and can cost as little as a few pounds a month. I pay £4.99/month with 100 mins of inclusive UK landline/mobile minutes. VOIP also open up the opportunity for cheap International calls, if you have the need.

A cut 25% of the overall depth of the slab is enough to act as an initiator so that if it does crack, then it will (should) crack in the cut. But, do you need to control the cracking. You've mentioned a float finish and a self-levelling filler if needed, so there's no plans to polish the slab. It's probably not important where it cracks (if indeed it does). Just make sure you use a Ditra mat type un-coupler if you are putting tiles down.

With no steel in the slab, I'd assumed your UFH pipes would be stapled to the PIR, well away from the top surface.

Then I'd put an upstand of perimeter PIR around the edges, more for a thermal break, but it will also allow some movement. My guess is you haven't got much room for this, at best the thickness of the plasterboard and skirting. There's a chance it will crack at the internal corners of the doorways, where, if you need to control that, you could put a cut in at each door way about 25% the overall depth (30mm - 35mm), as soon as it has cured enough to walk on.

A little more info please. Are the external and load bearing walls sitting on the slab/raft, or do they go down to a traditional foundation with the slab poured in between them, leading to narrow sections at doorways. There's no issue pouring 105m² in one go, my own is 465m² without any expansion gaps and done in a single pour, but all walls come down on top of the raft.

You can use typical UK boxes, the fixings holes are on the same centres, but the UK boxes are slightly larger and Loxone switch plates won't fully cover them. I used UK boxes, but got some stainless escutcheons laser cut to make sure the aperture was fully covered.

For a VoIP direct WiFi (not DECT) handset, I like my Grandtsream WP810. https://www.netxl.com/wifi-phones/grandstream-wp810-portable-wifi-phone/

Looks like an old land drain. The butt joint with no connection is intentional, to let the water get into the "pipe" and guide it out to the ditch/burn. It probably started off roundish, but has become misshapen over time. You can just build back up the earth around it and lay the displaced pipe back into its position. Then reinforce the band with what ever you plan.

Yep, there will be play in the joints, making it less accurate to dig with. Pins and bushes can be replaced, but if a number of joints are worn it may not be economic to do so. Doesn't cause me an issue away from the house, but I wouldn't have used mine to dig the drains around the house, for instance.

The Fibre is overhead in my road, but for me it drops underground from the closest telegraph pole and then crosses a field in my duct and up into the house. The ONT box that terminates the fibre is roughly 100x100x20, and does need power. You'll need a new router, connected to the ONT with an Ethernet cable. The main providers will supply the router with a new connection. Mine didn't, so I use a Ubiquity EdgeRouter X https://www.netxl.com/network-routers/ubiquiti-edgemax-edgerouter-x-router/?utm_source=google&utm_medium=surfaces&utm_campaign=feed_click&utm_content=surfaces_across_google&gclid=CjwKCAjwkNOpBhBEEiwAb3MvvcIdPhzpxKESCAg8miSEVS1Odc1QhIfic9KuCVMScgeLWO5UL7PFzBoC4aoQAvD_BwE If you do supply your own router make sure it can through put the bandwidth you want. The ER-X for example will through-put 1Gb/s, but oddly not on its default settings and needs a couple of tweaks to get the most out of the connection.

I felt a cheap Backhoe loader was very handy to have around, although I still brought in the right size 360 machine for quite a few jobs. For the same age and condition the Case 580 are a little cheaper than the JCB 3CX and the Ford 550 are cheaper again. I paid £4.5K for mine, and it has needed a few hoses replacing. Smokes a bit but still loads of power. Good for clearing and grading as well as moving stuff around, but mine has very worn pins. If I was to buy again I'd go for 4 wheel drive, extending backhoe and a £10K budget. I can't tell you if they're easy to sell as I've always got another job in mind for it, but it seems there're are plenty of people looking for them, as I've had a couple of locals try and buy it off me.

Openreach are flexible, so using an existing duct shouldn't be a problem. That's what they did with mine, even dug a hole in the middle of a field as their rods weren't long enough to fish it through in one go. They also routed the ONT to my Node zero point, centrally in the house, unlike their website which states it has to be on the inside of an external walk. It took a few visits, but they did a good install in the end.