ᐅ Insulation of the top floor ceiling (cold attic)

Hello everyone,

The construction is gradually taking shape, and the upper floor is now complete. The next step is insulating the top floor ceiling.

The attic will only be used for storage and will not be heated or insulated.

The plan is to build a course of bricks on the floor slab about 25 cm (10 inches) high, line the interior with two layers of 10 cm (4 inches) EPS foam boards with a thermal conductivity of 0.035 W/mK, and then pour a 5 cm (2 inches) clean concrete screed on top.

Is this the right choice of materials, or are there significant differences I should be aware of?

The roof structure itself will be covered with 18 mm (0.7 inches) boards and sealed with a membrane.

Does anyone have other suggestions?

Thanks a lot.

Zigenpeter86 schrieb:

The attic will only be used for storage and will not be heated or insulated.

What material is the top floor ceiling made of (ceiling construction)?

Zigenpeter86 schrieb:

The attic will only be used for storage.

Will it be accessed regularly or only occasionally?

Zigenpeter86 schrieb:

The plan is to build a row of bricks on the floor ceiling (25cm (10 inches) high), line the inside with 2 layers of 10 cm (4 inches) EPS foam with a thermal conductivity of 0.035, and then pour a 5 cm (2 inches) leveling concrete layer on top.

That sounds too complicated for me.

@Zigenpeter86
Roof beams in a cold roof must remain exposed, with no membrane installed on them. The underlay of the roof covering needs to be opened in certain areas to allow ventilation; otherwise, you risk creating a drip cave with all the long-term consequences.
Best regards, Nida35a

Thank you very much.
Yes, I need to discuss this again with the carpenter. Moisture would, of course, be disastrous.

My main concern is the insulation setup. Is this feasible as it stands?

@nordanney The top floor ceiling is a 24 cm (9.5 inch) concrete slab.
The room is used only for storage and is accessed every few weeks.

The reason for the 5 cm (2 inch) concrete layer is to add more mass to the ceiling in order to keep the heat out.

So, basically encasing Styrofoam in concrete? No way! There are walkable prefabricated elements available. Just lay them down, and that's it. Or is it a budget issue?