Alan Ambrose

p.s. are any of the supplier's panels better quality or are they much of a muchness?

I know this is not a common roof treatment here on 't 'ub, but we're planning to do one of these roofs shortly. I've watched a bunch of YouTube videos (of course) and am finding a bit of variation. Most are US or Australian videos so maybe part of that is due to the local weather. I've these questions: + I'm seeing eaves overhang from 25 up to 75mm. I'm thinking 50mm for our site, but am interested in anyone else's experience. + I'm seeing some quite complex examples of folded ends to the flashings - presumably for water resistance and aesthetics. Seems to me a trade off between how well you can do the hand folding (most don't do a great job) and just having cut edges. Anyone do this? + I'm seeing some use of foam closures at the eaves & ridge but not universally. Seems to me a trade-off between water resistance & ventilation. Any thoughts? + I'm seeing some use of 'Z-flashings' - sometimes under the ridge flashing instead of foam strips, sometimes along the eaves. Can't really see the benefit? On a quote I got from Cladco they added Z flashings ... but then they also added gloves, a measuring tape and a kitchen sink ... OK maybe not the last one.

I wonder whether you can grind and then fill the grinding marks. Car body filler comes to mind, although it’s a long time since I used that

Thanks for that. BTW your install looks v neat.

Not sure that Mike's example leaps off the page, but it's a lot better than zilch. I'm planning on labelling the end of the cables with a shrink wrap labeller, which should help a lot - ever found a misc T&E and wondered where it ends up?.

I'm wondering whether modulating the speed down, if that's possible, will make it quieter?

@Beelbeebub - I know this is a while ago, but I'm planning something similar, but portrait-style. Can I ask - did you use long rails, and if so which ones? The go to, Renusol, seems to advocate their short rails for profile roof.

If were me, I might replace any v dodgy wood like for like and maybe consider a coat of Bedec barn paint. Maybe I’m biased as we’re just about to clad our place with oak featheredge. What’s your overall objective - aesthetics? Better insulation? Reduced maintenance?

I don’t think there’s that much difference. About the same U-value, both have basic fire retardant. Mostly installed by the same crews with the same equipment. We went wood fibre, from memory slightly more expensive. Mainly because ‘wood’ rather than ‘paper’ - the wood fibre resembles the stuff that mdf is made of. The installation for both needs to be done well. I’ll write up our unfortunate experience and some recommendations when I get some time.

@-rick- you couldn't achieve the same with MVHR or wouldn't it have enough throughput?

I remember working in a very air-condition building in Bahrain. I used to open the windows to warm the place up. Luckily we could. Sometimes, I think, you just want to control the temperature rather than living in a isolated machine-controlled cocoon. Maybe you're cooking Xmas dinner for the family and want to stop it getting too stifling. Yeah open the windows but you would like to stop heating the place too.

Is there an advantage to putting an intermediate thin-ish insulation layer under UFH screed in a PH-style house? We have 300mm XPS with a 150mm slab on top and we plan to have 100m screed with UFH. But I’m wondering whether, say, a 30mm insulation layer and then 70mm screed would provide a shorter time constant for more rapid heating & cooling. I know some peeps subscribe to always heating to 20/21 degrees and cooling to 25 degrees 24/365 using the slab as a big heat reservoir. But that assumes you never want to change the temperature any, and if ever you do, then it’s going to take days i.e. a v long time-constant.

re: Cascamite Fairly obvious when you think about it, but proper structural glues have proper datasheets with glue strength under tension, shear etc. All the consumer glues just say 'super-strong' or some other unquantified nonsense. Having said all that, I can't see strength numbers for Cascamite. Strict prep, thickness, temperatures, application methods etc if you want to get the manufacturer's results. Worth bearing in mind that a lot of reactions are exponential with temperature and you can cheat the weather a bit by maybe using a fridge or a bucket of hot water. Also watch for peel strength when handling - may be not so strong even if the shear strength looks good in situ. Fill your boots

Thanks John

Err, CVC was what Nick recommended. @JohnMo interesting on your use of co2 monitor, I expect I'll need to do similar. Is it possible to post your link again for the eBay sensor - it just gives me 'error page'. BTW CVC quoted an extra £190 for the humidity sensor, which makes the total about £680 more than the Zehnder unit. I'd love to see what's in the sensor - I bet there's less than £10 of parts there. I've got the unfortunately named SHT35 humidity sensor in other parts of the build - the chip is about £6.

Curious - I can't think why it's ok for hot feeds but not for recirculating.

Ah interesting, I hadn't clocked the bit about the humidity sensor - a bit dumb that it wouldn't have. BTW cheapest places I could find were TradeSparky for the Zehnder and CVC for the Brink. This thing? https://www.ventilationland.co.uk/en_GB/p/brink-excellent-rv-humidity-sensor/5791/ Seems expensive. I was planning boost in the bathrooms and kitchen and maybe a co2 sensor in our bedroom as I think my other half is very sensitive to this - she wants the bedroom window open all year round - even in minus degrees.

Congrats, looks v tidy. >>> My understanding is that a female port (where a rubber seal and seat for that seal is absent) requires the mating male to be tapered thread (BSPT) and wrapped with thread sealer to make the joint I don't think that's right. My understanding is not to mix parallel and tapered unless you need a temporary bodge. I think most threads used in residential are parallel. Both parallel and tapered will need good thread sealer and I've used some cheap parts in the past that needed a bunch of thread sealer to work. That's all consistent with the instructions you quoted which said, in effect, 'don't use tapered parts here'.

OK for anyone 'following along at home' I decided on the Brink unit. I was leaning towards Zehnder but the physical size was an important factor considering the slopey attic it needs to fit into. I figured I needed 30cm above the unit to cope with the ducting. Not yet sure what I'll do re controls - the branded controls are stupidly expensive imo. I'll probably run CAT6 to the places where we want controls and/or sensors and assume I'll figure out the wiring later.

This is what it thinks about the mounting issue and that sounds good to me:

Ah thanks Mike. For anyone following along in future, this is what Gemini thinks, but having looked more closely at Ubbink's offering, I don't see any reason why it can't be shortened - it looks just like a bit of flexible insulated pipe that has some ends formed in it - and I think you could do that forming by hand without a problem.

A related question - has anyone here used (or felt the need for) some kind of sound absorbing feet or mounts in addition to whatever is on the bottom of the boxes?

Oh yeah I was only looking at Ubbink ones duh, I see DEC has a range e.g. Flexible silencer non-woven with connection diameter: 180 mm length 500mm 72620518 | Ventilationland Actually, maybe DEC is actually supplying Ubbink anyway as they look so similar.

Was going to use these to connect my MVHR box to the ducting (either 180mm foam ducts for external or the 180mm connectors on the plenums): Ubbink Aerfoam Insulated Mass Flow Ductwork Sound Attenuator 180mm These are nominal 1m and stretchy of course. The best connections I can see would bend to about 0.5m long - can I shorten them OK by cutting and forming something a bit like the factory ends?

>>> why are you limited to export volume? Well the DNO will always limit, even if it's only to 17kW on single phase - it's a risk thing with local voltages apparently. And we have planning permission to cover one roof and the 'cartlodge' with panels.