SimonD

That's funny stuff, for a moment I thought it was just bitument felt with a fleece backing! Looks like your roof was the size of a football pitch ?

It looks like it in the pic, but spec says 50mm just as with the cold roof

I can only guess it's down to risk of condensation behind the metal, but perhaps because of the riks of corrosion, there's a bit of a hedging against crap vapour barrier installation.

I got a strange feeling when I saw this thread as I was sure there's something wrong about warm roof build up and zinc standing seam. So I dug out my UK Guide to Good to Practice published by the Federation of Traditional Metal Roofing Contractors. Low and behold it recommends against using an unventilated warm roof buildup - or shall we say it diplomatically suggets to approach such a design with caution, especially with materials like zinc. So definitely listen to your roofing contractor, not your designer. The recommended design for a warm roof actually includes 50mm ventilation below the plywood/osb deck supporting the standing seam. Instead of writing and quoting loads, I've attached pictures of the pages so you can see for yourself. If you need any further details, let me know. HTH.

It looks amazing..and massive! That's one hell of a gable window and vaulted ceiling. Good luck with weeding out the samples.

Picture 2 shows a flatlock metal cladding. There are quite a few suppliers around in the UK - Zinc, Copper, Coated aluminium/steel, Stainless Steel. In picture 1 it looks like a metal fascia, again using a flatlock or simple lap.

Yeah, that's usually the assumption although with sufficient collector area (a lot), storage size and energy efficient house, many UK locations receive enough solar radiation to provide enough energy. There also isn't actually that much high quality research available specifically for the UK. My main problem was that I made the whole system myself - flat plate collector and storage tank included - and I made a lot of mistakes. Essentially they were pretty crap and I need to rebuild the whole thing. There's an interesting piece of research published on Science Direct in about 2018 looking at this which confirms there is some feasability of these systems. I don't want to hijack this thread but can dig out the link and post if you're intersted.

I'm most impressed by his ground heat bank. I played around with building a prototype out the back of my old house about 15 years ago but life, children and other things got me distracted so never developed it to work very well at all so had to bin it all. Wish I get the funds and time to try again someday.

You have an external layer, let's just call it a 'rain screen' for simplicity. This forms the outside protective layer against the weather, which could be your outer leaf of a brick & block, metal cladding, or timber cladding. Behind this, you'll typically design in a way for any water ingress to get back out of the building. Typically this is some kind of free space. However,it may also be achieved through use of building materials like a wood fibre external wall insulation with a lime render where is moisture does penetrate the outer skin, the material can buffer that moisture ingress and then naturally dry out when the weather improves. With a timber frame, which will typically sit behind such a screen, build method and detailing is important. The traditional and basic way to build up a timber frame is, from the inside: Plasterboard Vapour check - usually a membrane sometimes just a plastic sheet sealed at the seamsand sometimes a more high tech membrane that has a variable vapour check behaviour. Timber studs with insulation between the studs Frame sheathing - OSB/Plywood Breather membrane ventilation cavity - minimum 25mm outer skin. Now, there's a myriad of variations to this so this is just a basic illustration. The vapour check prevents warm moist air entering the timber frame/insulation layer. If it was allow to get in there, at some point the wall temperature would be cold enough to allow the warm moist air to condense, which would cause damp within the frame. The OSB/Plywood and breather membrane are there to allow some moisture to pass from within the frame to the outside, to prevent a harmful buildup of moisture while also providing some protection against ingrees of excess moisture from the outside. The problem as has been found in many timber frame buildings built in this traditional way is that the vapour check gets pierced during 1st and 2nd fix and not sealed up properly again. This allows the vapour to pass into the frame, causing excess moisture through condensation that can't be dealt with by typical insulation materials like glass wool. This moisture stays in the frame and causes rot over a long period of time. So your basic protection for the timber frame is proper detailing of the vapour check layer and your external membrane. With materials like wood fibre and sheepswool, for example, research has shown that because they're hygroscopic, they can soak of excees moisture in the frame (glass wool can't so the moisture condenses onto the material) and then pass it out to the atmosphere to even out humidity levels (a little like a hot item will cool down to atmospheric temperature). Because these material regulate this moisture in the frame better, it is better for the frame and actually reduces moisture levels with the frame long-term. This type of system build is approached slightly differently but again detailing is key. I've attached a document by BRE that talks about these natural insulations and how they can prevent bacteria and mould build up. The paper focusses more on vapour permeability but hygroscopicity is just as important. BRE Information Sheet Natural Fibre Insulation - IP18_11.pdf

I agree completely, but it also shows that it is not the building material in and of itself that is the problem, which was the question about cellulose.

Not necessarily, there are many examples across the country right now of newly built houses using concrete/stone/block/dryway/plasterboard-skim etc.developing bad mould problems very soon after occupation. I know someone who moved into a newbuild on a development only to find mould growing in the utility room within 3 months. The problem is more down to relative humidity and ventilation. Below a certain amount of humidity, mould will not grow on timber or cellulose or other materials. The wood fibre and cellulose (actually technically both cellulose) are treated, often with a borax solution to prevent fungal attack and for fire protection. Essentially what you need to do is ensure that your fabric is well built and detailed properly - so sufficient insulation, means of protection from ingress of damp and means of escape if damp does got into the fabric of the building. Internally you need to ensure good airtightness together with sufficient ventilation. Sufficient ventilation should ensure relative humidity remains within acceptable limtis within the house, but in addition it has been found in research that building fabrics that buffer moisture (i.e. absord excess moisture in the air and then release it at another time) can reduce relative humidity within the house by between 10-25%. Breathable fabrics include wood fibre, hemp,or sheepswool insulation but the whole wall system needs to work in concert. Hope that helps.

I think you may be referring to timber frame panel systems rather than sips. These panel systems can be open or closed, filled with different types of insulation, including pumped cellulose or woodfibre, sometimes done in the factory, sometimes completed onsite. With your allergies and sensitivity to mould, thus wanting to avoid excess moisture, I'd recommend you have a look at woodfibre breathable systems as the fabric of the building due to its moisture buffering capabilities. However, seeing your original post and that you have difficult access, stick frame may be the option, unless you can fit something like a spider crane in there?

That depends on the company supplying the cladding. Some companies can machine you up a bespoke profile. I used CedarDirect for my cladding and they did that for me. Here's a link to their main profiles page: https://www.cedardirect.co.uk/profiles/

My bad! I meant the sliding door! But as it's all doing your nut, I won't try to explain any more! ?

Mirroring what others have said, this is most likely entirely normal. It could just be down to a recent rapid drop in ambient temperature together will moist air within a new building. Keep an eye on it but you'll no doubt see it disappear soon.

I tried to use the LABC warranty but they wouldn't have me! ? As I understand it LABC warranty are underwritten by some other insurer and they will only cover builds that use products that are specifically approved under the LABC warranty scheme. Because a product has a LABC registered detail, or even BBA, doesn't mean it's covered under the warranty scheme. To get a quote you'll have to supply all materials used for the structure, including insulation system and they assess them as part of your application. This is okay for a bog standard build. I was turned down because I'm using woodfibre insulation even though the supplier had BBA certification. They were also very bureaucratic and interviewed me at length about my self-build background etc. I went with Protek. They were far easier to deal with and gave me a decent price for the whole thing.

So membrane about 50 quid plus VAT and clips maybe £75, the rest is then labour. I've been told that the going rate for installers on a day rate is between 180 - 220 depending on experience. Now, many of the smaller outfits will need to either hire or borrow a tray former (as to buy they typically start at about £10k even for a compact version) as well as a folding and cutting machine (again a few k to buy). They will also have to bring a second person to help with tray forming, but I'd expect that would only be a couple of days max with your design. Was this mentioned or covered in the discussion/quote? When I hired the equipment and tools myself for a couple of weeks it cost about £1200 and if this is included in the quote, it could make more sense. They might get the materials from somewhere that forms and folds the sheet but then that service plus transport can work out more than getting in the machinery. It's a bit of chicken and egg. Just a bit of speculation about why the cost might be coming in at it is. Another thought may be that you could modifiy your design to make it ever so slightly easier for the installer. I noticed that on the drawings you posted the window would require a couple of trays to be cut out vertically. If you could line up the edges of the windows to run in line with the seams of the cladding it would save some time to clip it into the reveals - but then you also want to ensure the seams are symmetrical with the corner of the building and masonry. Again just an idea that may help things along. I'm not entirely convinced the reveals are such as issue....

As @ProDave says, get it in as part of the intial enabling works so it's ready. There's nothing more frustrating that needing some power and having to sort out and run a generator. Our utility company provided the specs on the temporary electrics setup which basically came down to a large peice of marine plywood on fence posts with two boxes attached, one for the meter and the other for a consumer unit. The two are linked with long tails. My electrician then asked what I wanted in terms of supply and just wired up a few different sockets inside the box on separate rings, a couple of outdoor sockets as well as a ring to the garage. With sockets the choice is yours really, oh, and try and get as many sockets as you can!

Here is the photo of the detailing for info. As a comparison re price, last year I got a quote for zinc material only which worked out at about £35/m2 plus VAT for the standing seams and up to about £45/m2 for flashings. This was all cut and formed. Interesting to see the installers markup on here but it is skilled work.

Before I decided to take on our build myself, I spoke to contractors and looked at the insurance side of it all because several builders simply stated that they were fully insured and this turned out to be employer and public liability insurance, not all risks. I was also considering a JCT contract. Now, when I looked at the insurance side of this type of contract it became clear that the insurance specificied by the contract may in fact be quite limited in its scope and therefore opens up multiple risks that may not be apparent at the outset. I believe that a lot of people are falsely believing they're fully covered because the terms and their meanings are quite confusing. I think you need to go through the prospective cover in each instance to understand what is covered and what is not and then seek to make up any shortfall, or not if you don't think the risk is sufficient to do so. One item not listed so far is both owned and hired-in plant and insurance - many hire companies will not hire you plant unless you can first show relevant cover ( short term/ad hoc this cover can be very expensive - some hire companies may simply add 12% or so to the hire costs) and may not be included in an all risks policy. On mine it is an optional extra. All in all it's a minefield that unfortunately does require a good few hours of reading very boring policy documents and understanding the various risks you're exposed to during your building project. What has your architect as project administrator shared in terms of experience and input re this?

From looking at your image from the inside of the roof it looks like the steel does sit inside the thermal envelope as the joists filled with pir rest on a ridge beam that rests on the steel. Re the vents - do you have the detail drawings produced by your architect/technician for the roof? Even before your change from sheepswool to pir insulation and bitumen felt, there would have been a 50mm ventilation gap specified for the structure?

Nice one, thanks. Okay, the 6m limit will means some careful positioning of the manifold, no wonder it's recommended they're installed as close to the centre of the house as possible.

I found the drawing you uploaded to this thread now - I obviously didn't read it all carefully enough first time time round! Hope you have some joy finding someone. Re material requirements. From my experience, it's not the trays that are too difficult or time consuming, it's making up the flashings and depending on the girth required for the flashings it can considerable increase the total amount of material required because the flashings are typically cut from a 600mm width coil. I'll scan and upload recommended detailing for parapet, cladding and window reveals to illustrate later on.

Ah, yes I've now found them thanks. Doesn't look too complex at all.

That's exactly what happened with ours and I ended updoing it myself. Do you have any drawings for what you're looking to clad? I'm curious as to how complicated your proposed cladding can be ?