Benpointer

Thanks Nick, take you point about micromanagement, if the chippies were putting this in I'd have absolutety no worries but its the insualtion team from Cornwall and tbh they don't inspire 100% confidence. At one point they were suggesting pre-drilling the service cavity battens at 600mm centres to speed things up - but the cross battens are at 400mm centres 😬 I guess I was just wondering how much of an issue it would be if they did miss the cross battens. (Obvisoutl they are not going to miss the 122mm wide rafters else the screws won't bite.)

Hi All, Our roof build-up is a bit complicated but below 254mm easi-joists which are filled with blown cellulose, we have: Tyvek VCL 25x50mm cross battens, which were required to stop the VCL from blowing off the easi-joists when the cellulose was blown in 100mm PIR 38x50mm vertical service cavity battens 15mm PB and skim Here's a picture (albeit the easi-joists are shown as solid joists due to the limitations of my ubakus skills). The plan is to fix the PIR on lightly with half a dozen 120mm screws and washers, then pin it properly in place with the service cavity battens using 200mm screws through the cavity battens, the PIR and (ideally) the cross-battens, then into the bottom web of the easi-joists, by 37mm min. Ideally, the 200mm screws will hit the 25mm cross battens on their way but it's likely that some may miss the cross battens but of course they will still penetrate the easi-joist bottom web. If you can visualise all that, my question is: will the PIR deform if the screws are crossing a void rather than going through those 25mm cross battens? (Bearing in mind the force of the screws will be spread on the underside by the 38mm vertical service cavity battens.) If you can make sense of that and have a view, all responses would be appreciated.

We did exactly the same. Took 6 months and cost a bit, but no way would we have wanted what was planned.

A longer than usual blog - we’ve had a lot going on this week. We definitely reached site capacity with five vans and seven contractors on-site on Thursday and Friday. Seven pallets of cellulose bales arriving mid-week didn’t help space management either. The whole week got fairly stressful but somehow we seem to have got through it. Phew! Membranes The plan was for the team from SW Insulation to fit the VCL membrane to the vaulted ceilings, cross-batten with 25x50mm in preparation for the cellulose fill, then move on to the wall VCL and the additional 50mm PIR and 38mm service cavity battens on the walls. As I type that it sounds like rather a lot. It proved to be too much indeed… Our lovely vaulted ceilings turned out to be a nightmare to fit membranes to. Those, plus the ceiling cross-battens (essential to stop the cellulose blowing the membranes off the rafters) took three guys pretty much all week to do. So the walls will have to be tackled when the team return on the 11th August. We had no carpenters available Monday to Wednesday but on Thursday and Friday both Alan and Chris were on site. Chris rushed around closing all the external gaps around the roof edges off with OSB, while Alan worked flat out trying to keep ahead of the zinc roofers (see below). Closing off the roof edges was essential if we wanted to avoid the cellulose blowing into the rafter space and straight out across the neighbouring countryside. Before: After (ok, different section of roof but it all had to be done): The pressure to prepare for the cellulose fill was heightened a bit because I’d cunningly agreed to the cellulose team coming in on Saturday to fill the roof… Cellulose Ray and Devlin from JW Insulating arrived mid-morning on Saturday and worked straight through to 6pm to fill all the rafter spaces. It wasn’t plain sailing - they were worried the membrane wouldn’t hold. They had to put a some extra edge battens in to make sure the membrane did not get blown off due to the pressure of the fill and they had a couple of ‘blow-outs’ they had to fix. Apologies for my terrible photography but here is Devlin blowing the cellulose in to one section: After filling the first section they checked the density by cutting out a cylinder of the filled cellulose and weighing it. The core sample came out cleanly without disturbing the surrounding cellulose and after weighing they pushed it back in place and taped it up; it's amazing how the cellulose (which is simply pulped paper, treated to make it fire and mould resistant) seems to bind and 'set' in place once it is blown in. The test showed we were a tad over target density. I asked Ray whether that was a problem: “Not for you” was the reply. I assume they could end up using more cellulose than planned but they were happy to carry on. By the end of the day we had a fully-filled roof. Another milestone achieved! The photos don’t show it too clearly but the visual effect is as if there’s a vast silver duvet placed over the house. You can see the patches they used to cover up the entry points for the 'blowing hose'. We hadn’t realised the cellulose blower was 3-phase and came with its own noisy diesel generator which ran for 9 hours non-stop. Not much fun for our neighbours - we’re hoping they forgive us. Fortunately it was all done in one day, so peace was restored today (Sunday). Have we done the right thing? Choosing the best approach for insulating the roof has been tricky. With hindsight, PIR between the rafters might have been easier (especially since I now know you can get open web rafters with PIR between the webs, so no voids to have to insulate). Alternatively, maybe we’d have been better to have a warm roof with 200-250mm of PIR on top of the open web-rafters, which would then have served as service spaces for cables, pipes and MVHR ducting. That would have made for a very thick roof which would have been difficult to disguise though. But we liked the idea of cellulose fill for its eco-credentials and its noise insulation levels (especially with a zinc roof). Having said that, to get to our target u-value (0.1 max) we still have to add another 100mm of PIR on the inside; we'll leave some channels to run the MVHR ducting through. That’s the next job for South West Insulating when they return on the 11th August. Another option would have been to go for a more ‘Rolls-Royce’ solution like the timber frames offered by MBC, where they take responsibility for the roof insulation, VCL and airtightness. But although our costs for adding the insulation and membranes are higher than expected, it’s still going to be a lot cheaper than the MBC frame. Anyway we* have made our decision so we have to stick with it and see it through; it’s definitely proving trickier to implement than anticipated though! (*Well me - I can’t blame Mrs P.) Zinc roof The zinc roofers, Wessex Metal Roofing were also working through the week, finishing the main roof, fitting the small areas of zinc facade, and various facias, ridges, and gutters trims. They also kept Alan busy on Thursday and Friday making sure the necessary ply backings were in place to keep ahead of them. Scaffold issues: One area of challenge we have is the scaffolding. Ideally we need some limited changes. The scaffold company are in a fix though - too much committed work for the people available. In fairness they are communicating well and being open about their issues: fitters unexpectedly leaving or having to be let go, holidays, potentially over-ambitious work commitments... I have some sympathy but I sense it is going to be nigh on impossible to get them out for a minor adjustment any time soon. We’re going to need to think imaginatively to avoid being held up. I'm going to imagine everything's finished and we've moved in - feels better already. Next week: Work should start on the south-facing monoridge roof which is mainly solar PV panels with some slates round the edges. It’s a different roofing company because it seems the zinc roofers don’t do slates and vice versa. They sounded busy and stressed too, so I’m hoping they turn up. Aside from that, it’s a quiet week. We were supposed to be doing the blown cellulose roof fill but.. oh.. I see that’s already been done! Well done on getting to the end of that blog! Just for fun I've added a summary 'dashboard' below. This is turning into a weekly project report - sorry about that: old habits. Dashboard: Contractor days on site this week: 26 Contractor days on site since build start: 156 Budget: Currently running £8k over (Benpointer budgeting rule 1 breached - poor management 😂). Plan: On track to move in by Easter 2026. Issues and worries closed this week: Making the roof space airtight enough for the cellulose blow. Completing the cellulose fill. Confirming the window and door opening sizes match the ordered windows and doors. (Actually that was checked as ok by the Norrsken pre-install visit last week but I forgot to mention it, but its a big tick in the box and would be a huge disappointment to C4 had we been on Grand Designs.) Current top issues and worries: Scaffolding (see above). Velux flashings - more on this next week. Scheduling future deliveries: insulation, battening, cladding, render boards, MVHR, UFH kit, ASHP, HW cylinder, PV panels… all due in the next six weeks.

Too right! 😂

Too much glazing imo. Overheating, heat loss, where to place furniture, privacy, structure (how's that east corner actually going to be built?), aesthetics... But... Surely the joy of self-build is that within reason we each get to have the house we want, not the house some builder thinks we might want? Just make sure it is the design you want, not just the one that happens to be approved for that plot at the moment. Project management: I was a PM for 20+ years before I retired (in finance, not building, admittedly) but I am finding PMing our own self-build reasonably stressy and challenging. Fortunately the buzz is outweighing the worries for me at the moment but if you aren't used to managing complex projects with a lot riding on them, think very carefully before diving in. Finally, this thread is very interesting - from people who have been there:

When I was a lad, a gullible friend of mine reckoned he could earn £500 a day at the local kipper factory. I said "£500 a day? What are you smoking?"

I thought I'd post this lesson I've learned, and disaster (hopefully) narrowly avoided, in case it helps anyone else. Also, some of you may be able to clarify the mysterious world of Velux flashings in a way I can understand. We are having three SK06 triple-glazed Veluxes fitted in our standing seam zinc roof - indeed they are already fitted. When I ordered them, my local builders merchant (Sydenhams) offered a price as good as I could get on-line, so I went with them. I explicitly requested flashings for a standing seam zinc roof but I could not work from the very poor Velux website what the Velux code for those flashings is, so I left it for Sydenhams to liaise with Velux (mistake no. 1). The windows were ordered and I was told I needed EDW flashings at £112 each (wrong). Wessex Metal Roofing visited the site on 14th July for a pre-installation check and their rep Graham straightaway said, they're the wrong flashings, and that we needed ZWC flashings. So I called Sydenhams who took the flashings back and credited me. They then liaised further with Velux but this time Velux suggested the EDE flashing kit, claiming not to recognise 'ZWC'. The EDE kits are an eye-watering £588 each, and also on a 22 day lead time. Worried about the lead-time, I failed to challenge this new code (mistake 2) and the order went in. Meanwhile the windows had arrived, been fitted, and the zinc roof put in place... crucially with soldered zinc upstands around the Veluxes. Being that way inclined, I spent some time trying to understand the EDE installation process. Not that Velux's website was any help. Download the installation guide for your product it says, but EDE is not to be found... https://resources.velux.co.uk/technical-resources/flashings-installation-products-guides Eventually I did manage to track down a copy via an online supplier site (can't remember which). It soon became clear that the EDE flashing kit needs to be fitted before the roofing but our zinc was already on 😱. Roofers were unfazed: "don't worry the flashings just clip on". Eventually it dawned on me that I should have stuck to my guns and insisted the ZWC flashings (just £43 each, so £545 cheaper than the EDEs!) Sydenhams were pretty good again, cancelled the still not delivered EDWs, and suggested I'd do best to get the ZWCs online. Which I did. They arrived at 4:30pm on Friday, just after the roofers had left for the week. I am praying that on Monday, "they just clip on"... My conclusion is the EDE is a full flashing for a metal roof that is not going to have custom-made zinc upstands , whereas the ZWC is what you need if you have a custom-made metal upstands... but I honestly can't be sure. Here's hoping that Monday brings good news, and my flashing worries are over! Meanwhile, I would just like to say that the Velux website and online support is utterly *****! .

I'm still smarting over the £1000 council 'legal costs' for a 6 page "standard template" S106 agreement to confirm as self-builders we'd live in the property for at least 3-years.

Just the once, and I'll try to remember

Please Sir - tell me!

Well done! Looks like a lovely view. Keep us posted on progress.

Well said. Whilst I have immense admiration for those of you taking the full hands-on approach, physically we can't do that, so we are sourcing and coordinating subcontractors who can. Whichever way is right for you, I say.

Show what I know - I thought asphalt and tarmac were the same thing.

What's under the boards? If it's a ventilated floor space that's going to be cold, especially so if there's no membrane. We're renting a cottage with a very similar looking floor: cold, drafty, scratches easily, marks badly... Personally I'd lift it, insulate between the joists, fit an airtight layer, and replace the softwood for a pre-finished engineered or solid hardwood floor of your choice. You might even be able to sell the softwood floorboards on to offset the cost. (When we did our previous house refurb we picked up some 3/4" solid, tongue and grooved, prefinished American oak flooring for a snip (surplus stock from the US). That proved to be really stable, took 15 years wear and tear and was only just looking like it needed refinishing when we sold up. (PS Check the floor is cross-ventilated before doing anything and if there's a floor vent in the room make sure you keep it - it will be for the fire / woodburner if you have one.)

As mentioned last week, the zinc roofers asked if they could start a week early(!) and so, on Monday morning along they came - Brian and Tom from Wessex Metal Roofing in Salisbury. The first couple of days were mainly rolling out long zinc profile sections from the back of their van, then these proceeded to be fixed on to the 18mm ply sheeting that Alan the Chippie had laid the previous week. Three triple-glazed electric Veluxes arrived from the builders’ merchants (I forgot they were coming last week tbh) and while I spent ages looking on the (frankly rather terrible) Velux website for installation instructions and videos, Mrs P. pointed out to me the the CCTV seemed to show the guys had already fitted them in. “Oh, I’ll stop looking then.” The moment the roofers realised we have CCTV 😂 : By the end of the week most of the zinc panels have been fitted, plus some facias and gutters. I must admit that when we signed up for a standing seam zinc roof I assumed it would actually be ‘zinc’ - but it appears to be white plastic, with ‘zinc’ written on it - we've been done! Apparently it’s best to take off all the protective film at once otherwise it can start to age differently. For those interested, we’ve opted for VMZinc Plus in ‘Quartz’. We can’t wait to see it ‘undressed’. Although most of the zinc panels are now on, there is still a fair bit for Brian and Tom to do including some vertical clad sections on the far side of the house, plus facias, verges, and a ventilated ridge for the south-facing monopitch roof (on the left of the photos). Also they have the zinc gutters and downpipes to fit. They are expecting to finish the week after next. We’re also hoping that the work on south-facing roof, which is mainly 30 in-roof SolFit solar panels with a band of slate tiles around them, will start w/c 4th August. So with luck by the end of that week, all the roofing, gutters and downpipes will be done. While the roofing carries on through next week we also have South West Insulating (SWI) from Redruth on-site to start fitting the VCL/Airtightness membrane and the additional internal wall and roof insulation . The sequence for the next three weeks inside should be: Week 1 - South West Insulating - VCL to roof, then VCL + 50mm PIR + service cavity battens to walls. Week 2 - JW Insulation arrive from Essex to blow cellulose into the roof (a 254mm cavity formed by the Posi-joist open web rafters). Week 3 - SWI back to finish roof works (100m PIR + service cavity battens). Let’s see how well that masterplan survives the heat of battle 😬. And finally… On Friday, evening, after yet another huge tidy-up of the site by Mrs P., we hosted about 20 local friends for beers and a chance to look around the skeleton of our house. We had beautiful weather and of course everyone was very kind about the house and what we are doing. A lot of really great questions as well about the technical detail of the build - I was surprised how genuinely interested many people were and I suspect a few were thinking they might have a go at self-build themselves.

It's not really about whether to register or not. I did because I read somewhere that the HSE are never interested in small projects* and if we did have an incident, and it looks like we should have registered, the hot water we'd be in would probably be quite a few degrees hotter. Also, it was free to register so no apparent downside. Having said that, I perfectly understand those who decide not to. I just thought it would be interesting to track days on site and see at the end of the project whether I actually needed to register (* I'll be sure to let you all know if we do get a visitation from the HSE - I'll be regretting registering and you can say 'told you so' 😉 )

As discussed elsewhere on here, you should notify HSE of a build project if: "The construction work is expected to last longer than 30 working days and have more than 20 workers working at the same time at any point on the project or exceed 500 person days" (my bold). https://www.hse.gov.uk/construction/cdm/faq/index.htm We were never going to trouble the first criteria, there is neither sufficient room on site for that many people, or in my brain to coordinate that amount of work at once. I pondered the second criteria for some time. Our frame was built in a factory off site but most of the rest of the build involves people on-site doing stuff. 500 days at, say £300 per day = £150k and we will be spending a fair bit more than that on the build. But then again how much our spend is materials? In the end I decided to register the build with HSE via an F10 form, just in case. But out of curiosity, it occurred to me that with the aid of our excellent Reolink 4G CCTV I could easily keep an approximate track of how many people work how many days on-site. So that is what I am doing. So far the groundworks, frame erection, scaffold and half the roofing has totalled 130 man days. Lots still to come of course, including: insulation & membranes, window fitting, UFH, screed, cladding, 1st fix electrics and plumbing, plastering, flooring, joinery, 2nd fix, kitchen, decorating... (landscaping?). Will reach 500? Touch and go, I think. Has anyone else kept stats of their build?

Yes, the original photo wasn't easy to view at all. Here's a (hopefully) better one of the base of one pier, OSB racking is on the far side.

Just to add to this, an hopefully close it off... Gus has not been around to answer my PM to him but we have now received the structural calculation pack by Paramount Structural Engineers - https://www.paramountse.co.uk. Whilst the detailed calculations are rather impenetrable for me, I can see that they have based their calculations (including stud and sole plate loads, and wind loadings) on the design, as-built. The design itself has 3 cripple studs supporting each end of the lower steel with two further studs fixed alongside at each end to support the higher steel. The walls either side have OSB racking on one face. None of which was very clear in the photo I posted and Gus commented on. Anyhow, I am happy the design is sound. If we can't rely on the opinion of an established firm of SEs we are on very dodgy ground. Thanks though to Gus for raising this.

Hi, thanks for raising this Gus - I have PMed you some more details just to check I am not misunderstanding your concern.

He's a very clever guy. Like so many good trades people, he very inventive and has a great eye for what looks right and what will work. We're very lucky to have him.

Last week our timber frame structure shot up. This week was supposed to be the second week of a two-week frame installation but the team finished on Tuesday, having worked through the weekend. And off they went, but not before I persuaded them to stand still for 30 seconds for a snap for posterity. So here they are: Brandon, Jake and Callum - Great work guys! Their early finish allowed our chippie Alan to press on with the 18mm ply required over the roof for the zinc roofing. 60+ sheets of 18mm class-3 exterior ply were put up amazingly quickly by Alan with a bit of assistance from his pals on a couple of days. The only lifting gear on site at present is a Genie lift we bought, guessing it would come in useful, and Alan made great use of it to create a novel “Ply Sheet Lift 'n' Slide Sledge”. I pointed out to him that I’ll be patenting that idea, since all intellectual property rights obviously sit with us as site owners. He seemed unbothered. Next week Alan is away on hols (not in my plan, are you sure Alan?!). Thus we were going to have a quiet week which I labelled ‘contingency’ to make it sound more important. But Brian from Wessex Metal Roofing phoned me today (yep, Sunday) and asked if they can start the zinc roof a week early... “Oh, go on then.” So off we go again - more fridge-stocking required! Timber frame details Last week I promised to say some more about the frame structure, so at the risk of boring those not wrestling with the same choices we faced,t here’s some more detail (skip to the 'And finally...' section if you’re not interested): We decided early on that we wanted a factory-built SIPS or insulated Timber Frame structure. We’d used SIPS on our previous house with positive results. I contacted a dozen or so companies and received quotes from eight companies for supply and installation of the insulated structure: four SIPS companies and four Timber Frame. The price range was surprising: the most expensive was 240% the price of the cheapest. Of course each quote had a slightly different scope but factoring in the work we’d need to do to get them all to the same level of insulation and airtightness, the price range was still over 200%. In the end, shortlisted Turner Timber Frames, whose price was near the lower end but leaving us with a fair bit to do once the structure was up, and MBC who unsurprisingly were at the top end for an impressive approach and structure. After talking it through with Geoff our architect, he agreed with us that the price difference was so big it was hard to justify the MBC approach. Therefore we opted for Turners… And they have been really great to work with throughout. Matt, their Timber Frame Manager, has been very helpful and responsive. Their price has not gone up at all as we moved from initial quote through to signed-off design (in fact they came in below their initial estimates for steels and crane hire). They kept to the agreed timescales. Their sub-contracted installation team were really good, as previously noted. The quality of the frame appears very good to my untrained eye… and Alan our chippie seems impressed as well. The structure we bought is Turner’s Super Advanced timber frame: 140 × 38mm studs at 600mm centres with 9mm OSB sheathing and a breather membrane on the outside. The pre-fitted insulation is 120mm PIR and it fits really precisely everywhere. We opted for an additional 50mm PIR inside to give us a wall u-value of 0.13, recognising that in so doing that we had to fit the VCL, 50mm PIR, and 25mm service cavity battens ourselves (though all are supplied by Turners as part of the package). Some other frame or SIPS suppliers do all that for you, but at a cost. What you see in the pictures is the frame before we fit the VCL and additional insulation - I think you can see how tight that pre-fitted insulation is - it’s really very snug all round. I was worried we might have gaps to fill but there are none. The roof is open-web 254mm Easi-joist rafters with 11mm OSB, which we paid Turners an agreed addition to have their installation team cover with breather membrane and vertical 50mm battens to create the ventilation space we need for our zinc roof. Turner’s approach means we have no unsightly purlins to interfere with our vaulted ceilings. But the roof does present a challenge for insulation. We decided to opt for blown cellulose within the roof space which should fill the open web joists, plus 100mm PIR below the ceiling, to get to a u=-value of 0.09. It meant we had to find someone to fit the VCL below rafters and make it airtight (see below). We also have to fill in all the roof perimeter gaps to stop the cellulose blowing out, and we have volunteered Alan for that. He’s delighted (I assume). We always knew the blown cellulose was going to cost a fair bit. J W Insulation from Halstead in Essex came in with a good price and are lined up to do the work w/c 4th August. Before that we need the VCL membrane fixed the roof. In the end we decided that a specialist company would be best for fitting the ceiling VCL, the airtight wall membranes, and additional internal insulation. We have South West Insulating from Redruth coming along from 28th July to do that work. So we have a busy few weeks ahead - I am hoping all that activity meshes together and the various teams don’t get in each other’s way (and the drinks fridge is big enough!). And finally (for this week)… Frustratingly, despite the frame being up for a week now, as a wheelchair user with a 300mm high perimeter foundation wall to get over I have not been able to see inside. Until today… Although I promised Mrs P. that this build would involve no heavy lifting or lugging on our (i.e. her) part, today she has been heroically moving pallets, ply sheets, and 4m scaffold boards into place, which we have screwed together make a wheelchair ramp! So today for the first time we could both enjoy the shape of our new house from inside. And we love it! It's impossible to capture in photos but we are both really pleased with how it feels, the room sizes, the vaulted ceilings, the overall layout… everything. Which is just as well really as it’s a bit late to change the design now 🙂

…well, the shell of a house at least. What a crazy week. We chose the factory-built timber frame route because we like the idea that the shell goes up within a few weeks. But the pace of progress this week has been startling. The frame erection team of 3 arrived at 7:30am on Monday. A big yellow crane arrived at 8:00, with the frame arriving on an artic by 9:15. First off: a careful check shows that the frame fits the footings. Hurray! In fact the footings were within 3mm all the way round, which is credit to the groundworkers. From then on it was flat out and 7 days later the structure of the house is pretty much complete. Those guys do work very hard though - long days under a blistering sun, and straight through the weekend. They are aiming to finish the tidying up by Tuesday, get Turners to sign-off the frame, and head off home to Essex. A great crew - real grafters. We’ve also been very lucky with the weather of course, though the erection team certainly wished it had been cooler each day (we’ve had highs of between 28C and 32C for the last 5 days). We kept them supplied with cold drinks and ice-creams as best we could and we’ve installed a fridge in the workshop which has been popular. The frame itself looks very good - it all appears to fit together tightly from what we can see. No gaps around the insulation, or between the panels. I’ll say more about the frame structure next week but for now here are some pictures of daily progress, plus some at the end showing some of the detail: This time last week: Monday: Tuesday: Wednesday: Thursday: Friday: Saturday: Today - Sunday: And a few of the details, some taken earlier in the week: And finally, for both of you who made it this far, one of those oak posts I cut and chamfered last week (the softwood beams will be hidden in the soffit:

I looked at adding the ComfoPost to our Zehnder MVHR but in the end it seemed like an unnecessary complication and expense since we are going to have UFH anyway and we can run in cooling mode from our Panasonic ASHP. The need for insulated ducting on the supply side is a big negative imo. It remains to be seen how effectively UFH in cooling mode works for us but it's got to be better than nothing.