ᐅ Floor construction with ventilation system on the upper floor

Created on: 25 Mar 2018 21:04

Hello,

for our planned single-family home (urban villa, 2 stories without a basement), which will be built by a developer, we want to install a mechanical ventilation system with heat recovery. The ventilation installer would like to use oval ducts measuring 115x51mm (4.5x2 inches) in diameter. These ventilation ducts are intended to be installed within the floor structure of the upper floor, between the concrete slab and the screed. The floor structure currently looks like this:
- 1.0 cm (0.4 inches) surface covering
- 6.5 cm (2.6 inches) cement screed CT-C25-F4 with fibers S65 H45
- 10.0 cm (4 inches) impact sound insulation
- 18.0 cm (7 inches) reinforced concrete slab C20/25

Now the construction manager has expressed concerns and says the floor structure needs to be raised by 4 cm (1.6 inches), which would increase costs by around 1200 euros.

If I understand correctly, the ventilation ducts (5.1 cm (2 inches) in height) would have sufficient insulation both above and below (within the 10.0 cm (4 inches) impact sound insulation). I have illustrated this in the attached image. Is there something fundamentally wrong here?

Thank you for your advice.

Schematic drawing of the wall construction with insulation, screed, and concrete slab

blackm8826 Mar 2018 12:44

#13

In our case, the mechanical ventilation ducts (metallic and rectangular) were installed directly on the concrete or wooden floor, alongside the water and electrical conduits inside protective tubing. Insulation material was placed around the ducts and granulate on the remaining surface. Above that, additional insulation, a vapor barrier, and then the underfloor heating were installed. The minimum coverage thickness above the mechanical ventilation ducts was said to be around 6 cm (2.4 inches).

lin0r8715 Dec 2019 12:57

#14

blackm88 schrieb:

In our case, the mechanical ventilation ducts (metallic and rectangular) were installed directly on the concrete or wooden floor, alongside the water and electrical conduits inside protective tubing. Insulation and loose-fill insulation material were applied around the ducts. On top of that, additional insulation, a vapor barrier, and then the underfloor heating system were installed. The minimum coverage above the mechanical ventilation ducts was reportedly about 6 cm (2.4 inches) …

And was the supply air coming from the floor?

If possible, please share a picture.

blackm8815 Dec 2019 13:03

#15

Hey!
We have supply and exhaust air vents in the ceiling everywhere, except in the two children's rooms. There, the supply air is on the wall at a height of 3.2m (10.5 ft) because there is no “flat ceiling” in those rooms.

Chris251113 Mar 2020 11:59

#16

Is this also applicable to kitchen exhaust? We will have a kitchen island, and I would like to route the exhaust down through the floor to the exterior wall.

K1300S14 Mar 2020 08:14

#17

Are you referring to a steam extractor? In that case, the ducts are definitely larger, as it needs to move significantly more air. Otherwise, it’s not a problem at first. You would just need to check where the duct comes out of the wall, as it is likely in the splash zone of the external wall.

ivenh014 Mar 2020 08:23

#18

In our case, the flat duct for the extraction hood runs on the concrete ceiling toward the exterior wall. There, it rises within the exterior wall and finally exits at about 30cm (12 inches) above the finished floor level. If needed, I can upload a sketch from the kitchen installer.
However, this is standard practice nowadays and nothing unusual at all.

ᐅ Floor construction with ventilation system on the upper floor

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