Mike

I have a 40m² apartment several floors up that I'll be stripping and modernising in France. Despite the high levels of insulation + airtightness + external window blinds that I'm planning, it will get pretty hot in summer, so I'd like to take the edge off that. There's no chance of installing an external heat pump, due to conservation area restrictions and the only place to hang it being within 2m of a couple of bedroom windows. However it might be possible to draw in and expel a modest amount of air through a duct - either through the external wall, or potentially by lining a couple of old chimney flues - to supply a small internal duct-mounted (or at least duct-fed) heat pump. It could either be connected to in a post heater / cooler to cool the air in the separate MVHR system, or I could connect it to the planned wet UFCH system. Does anyone knows of a suitable heat pump (that's also fairly small, quiet and affordable!) that might work? Ideas welcome.

I'd agree with your first 2 points, but it's an existing roof that needs replacing (not on my house). Your 3rd point is quite correct too, but I'd not envisaged it being permanently in switch on - just manually switched on for a monthly test Except that it's a GRP flat roof that's failed prematurely. That's not to say that there's an intrinsic problem with GRP but, since it's formed in place rather than in a factory, it is (like other types of flat roofing) still subject to problems of sub-standard installation.

Does anyone have any experience of embedding moisture sensors in the substrate of a new flat roof, in order to detect future leaks? Or any suggestions of how it might best be done? Not that leaks should happen for many years, but if/when they happen, it would be cool to get an early warning, rather than waiting until water damage becomes visible...