Flat roof dMVHR
Posted: Thu Jun 19, 2025 12:40 pm
Does anyone have any experience of extracting with a DMVHR to a flat roof?
The long story is that our house has a downstairs shower room which has no external wall around it and flat roof above it. The room has a nasty 1980s single skin aluminium and polycarbonate roof light which I'd like to get replaced with a triple glazed rooflight. The existing roof light has trickle vents but also gets covered in condensation for half the year.
So what I'd like to do is have a DMVHR installed with the vent side positioned in one of the cupboards to the side of the room and then venting via a flat roof vent.
My first question is - would this work? Wouldn't condensation form in the vent side of the DMVHR? Has anyone had to deal with something similar?
This is all part of project to replace the flat roof (as it could be quite old), insulate with 150mm celotex between the joists, fix the shower room ventilation, and add a chunk more PV. I've got plans for the latter which are approved by The Boss, and which I'll share in a thread in the PV forum.
The long story is that our house has a downstairs shower room which has no external wall around it and flat roof above it. The room has a nasty 1980s single skin aluminium and polycarbonate roof light which I'd like to get replaced with a triple glazed rooflight. The existing roof light has trickle vents but also gets covered in condensation for half the year.
So what I'd like to do is have a DMVHR installed with the vent side positioned in one of the cupboards to the side of the room and then venting via a flat roof vent.
My first question is - would this work? Wouldn't condensation form in the vent side of the DMVHR? Has anyone had to deal with something similar?
This is all part of project to replace the flat roof (as it could be quite old), insulate with 150mm celotex between the joists, fix the shower room ventilation, and add a chunk more PV. I've got plans for the latter which are approved by The Boss, and which I'll share in a thread in the PV forum.