SBMS

In two minds… about to start on our flat roof. Originally had planned for 200mm PIR as a warm roof. Due to a number of design issues we are looking at reducing this down and potentially looking at a hybrid roof. have had an interstitial analysis done by Unilin. By their reckoning if we put 100mm between joists and 140mm on top that yields no risk of condensation.. My thinking is whilst aesthetically we can reduce the parapet wall by a course (60mm) to improve aesthetics… is it worth it for the ‘risk’ perceived with a hybrid roof? Anyone else done this?

Probably not answering your question but I spent ages going round in circles on this and decided to go wall mounted fan coils upstairs. Panasonic aquarea system. Means we can do heating and cooling. 2 Temperature zones (natively supported by the system) so can run UFH and fan coils at different temps (low if needed for cooling). I’m not sure the cost of UFH upstairs is justifiable but I do think the cost of proper cooling (AC level cooling) is justified - the way our summers are going. Got Panasonic coming out in a couple of weeks to provide a technical assist on the system design if you had any questions

Am using UFH - why is this not ideal? Sorry I am not the OP re the large garage/ pool. Mine is a 10mx6m pool hall with a ln 8x3m in ground swim spa in it.

Got You - but that’s not its normal mode of operation? That would just be a mode to put it in extract only?

That’s interesting… does that mvhr unit not pull in outside air and extract indoor air?

Panicked when I read your first reply!! Though I’d f’d up so thanks for clicking! I think that’s a good idea try it for a bit and see. I’m wiring for a wall mounted dehumidifier as well with a condensate drain just in case but can try without and see? I’m guessing that in the summer if it’s humid outside that through wall mvhr would struggle to dehumidify?

Was significantly more expensive for me for similar thermal properties.

Thanks. I might stick with my vent axia through wall mvhr as main house mvhr in now. I don’t known if ill Also need a separate dehumidifier for when the roller cover is open and pool is in use? https://www.fastlec.co.uk/vent-axia-hr500?utm_campaign=smartsh&gad_source=1&gad_campaignid=17190426677&gbraid=0AAAAAD8Nz9eer1SHaUpDoIs41_1ki6pT_&gclid=CjwKCAiAlMHIBhAcEiwAZhZBUsg0RPymwbeyCjlQAQTXTAJLWtxkDB6mW6L364S1toSkcRFJIjFJixoCix4QAvD_BwE

Did the rounds settled on warmcel. About 200m2 at 304mm deep is about 6.5k installed. Was by far the cheapest. The cellulose is currently on site due to be installed in next couple of weeks so can let you know.

Which MVHR units out of interest? We are installing an indoor in ground 8x3 swim spa and was looking at through wall mvhr units. Most manufacturers I asked weren’t willing to certify their units due to risk of corrosion, so I can’t use our zehnder whole house unit in the pool room.

I agree. From the touch tree I’ve had I would say that the retro touch are much better quality and less than a quarter of the price.

Ah! Well that answers it! So no physical depress on touch tree either?

Random question.. I bought a test touch tree this week. The corner buttons don’t actually seem to depress at all - is this normal? Are they somewhat capacitive or have I got a dudd?

I’m not 100% convinced they are LEDs, it’s really hard to tell. When I look close they look like solid plastic decorative bits. But as Spinny says on the website on other ranges retouch describe them as uv stimulated! Would you recommend in general @Thorfun? Any tips on sockets - am doing a mix of touch trees, touch pure and 2x touch flex. Am hoping to wire up the touches in the bedrooms to the fan coils… that’s another challenge trying to understand how the 0-10v input works.

We are doing loxone so all switches are wired back to digital inputs. All led strip power fed centrally as well, no local transformers.

Ah do they? Where do they say that I can’t find that!

currently looking at these light switches for some of our non loxone touch switches: https://www.retrotouch.co.uk/retractive-momentary-switches/MM11MB-R2RB.html does anyone know if the little white led looking indicator works when the switch is fed with 24v?

Just watched it - absolutely crazy! Unfinished and on the market and the program is the biggest advert for it now as well. Hope they finish it and get to keep it.

We had a parapet wall so the cavity wall continued up past the edge of the roof.

Is 1800 include all fittings as well - flooring built in furniture etc as well? These things quickly add up

Have you any parapet walls? We went warm roof - was too difficult to detail ventilation.

I’m not doing it for the sake of it and I really don’t follow this logic - I don’t know where summers and temperatures will be in ten years - and I don’t know exactly how the house will respond to summer temperatures until I’ve actually built and lived in it. Why the aversion to a proposed system that can do exactly what you suggest (run at above dew point) but also have the capability to run lower for the sake of a mixer valve and temperature sensor? I can’t understand why future proofing in most contexts is seen as a good thing by self builders but I seem to be proposing heresy here in giving more flexibility 🤷‍♂️

Sorry Gus I'll be honest I'm not sure what you mean about designing a system based on what is available above the floor?? For clarity: am doing UFH downstairs, and wall mounted fan coils in bedrooms upstairs? Not sure why I would need 'more loops' for FCU cooling? They are on one circuit, drawing water from the buffer? Might have misunderstood though.

Thanks and understand everyone’s points. Let’s just assume I understand everyone’s points that I may not need to run it that cold and could run above dewpoint temp. Id still like to size my FCUs appropriately and can see no downside to have a system that can do 10 deg supply - even if its only on a couple days a year. From the literature it looks like the heat pump does provide this and it’s design is quite similar to my niaive design that didn’t rely on the Panasonic controller??

Thanks for this but seeing as I have already installed and lagged pipes and CAN run at 10 degrees (which also dehumidifies) I’d like the option of it. Would also like FCUs sized appropriately and not oversized to cope with a reduction in output when running at 16deg. If it turns out I don’t need to I can simply set both zones to 16 degrees, enjoy a better COP and achieve the same. Im just keen to understand if the heat pump natively supports this…