ᐅ Insulation of Basement Ceiling with Mineral Wool – How to Install
Created on: 8 Dec 2022 10:16
H
Herbert 80
Hello. I have a house with a full basement.
Currently, there is no insulation applied, so the boards are directly visible.
I have now received quite a few stone wool boards with a thickness of 60mm (2.4 inches) as a gift.
These boards are coated on both sides with a firmer white material to allow the boards to be glued directly to the ceiling.
The problem is the ceiling height.
60mm (2.4 inches) is too thick for me. I would have to cut the boards in half, so to 30mm (1.2 inches), to still be able to walk around (unfortunately, very low ceiling height).
However, after cutting them in half, the white coating would be removed, so I would have to glue the stone wool directly to the ceiling.
I would cut them with a pruning saw with a good guide to keep the cut surface even.
Does anyone have experience with this?
Best regards, Herbert
Currently, there is no insulation applied, so the boards are directly visible.
I have now received quite a few stone wool boards with a thickness of 60mm (2.4 inches) as a gift.
These boards are coated on both sides with a firmer white material to allow the boards to be glued directly to the ceiling.
The problem is the ceiling height.
60mm (2.4 inches) is too thick for me. I would have to cut the boards in half, so to 30mm (1.2 inches), to still be able to walk around (unfortunately, very low ceiling height).
However, after cutting them in half, the white coating would be removed, so I would have to glue the stone wool directly to the ceiling.
I would cut them with a pruning saw with a good guide to keep the cut surface even.
Does anyone have experience with this?
Best regards, Herbert
A
Alibert876 Jan 2023 14:20Tolentino schrieb:
10cm (4 inches) PUR (thermal conductivity 0.025 W/mK, aluminum foil facing) has a U-value of 0.235 W/(m²K). Nonwoven facing (thermal conductivity 0.028 W/mK) would have 0.261.
14cm (6 inches) mineral wool (thermal conductivity 0.040 W/mK) has 0.266 W/(m²K). May I ask another question:
I can get a leftover Iko enertherm f4 (flat roof insulation) 100mm (4 inches) thick from an acquaintance.
Can I also use it for the basement ceiling and the upper floor ceiling?
Thanks!
Alibert87 schrieb:
May I ask something again:
I can get some leftover Iko enertherm f4 (flat roof insulation) 100mm thick (4 inches).
Can I also use this for the basement ceiling and the upper floor ceiling?
Thanks! You can use any insulation material on the underside of a concrete basement ceiling. Vapor permeability doesn’t matter since the concrete ceiling is practically 100% vapor-tight. UV resistance is irrelevant, and compressive strength and fire protection only matter in garages. So: yes.
If it has an aluminum foil facing, I would recommend using mechanical fasteners, otherwise the whole thing might not hold properly.
A
Alibert879 Jan 2023 12:12dertill schrieb:
You can use any insulation material on the underside of a concrete basement ceiling. Vapor permeability doesn’t matter because the concrete slab is almost 100% vapor-tight. UV resistance is irrelevant, while compressive strength and fire protection only matter in garages. So: yes.
If the insulation has an aluminum foil facing, I would recommend mechanical fixing with anchors, otherwise the whole setup might not hold. Okay, thanks.
Is the thermal conductivity value (WLG) of about 0.022 the same for all PU/PIR insulation regardless of thickness? From my research, that seemed unusual. Ideally, the thickness should be a maximum of 8cm (3 inches) and applied with adhesive (so not double aluminum foil facing).
Alibert87 schrieb:
Is the thermal conductivity value (WLG) of about 022 the same for every thickness of PU/PIR insulation? According to my research, this seems unusual. Ideally, a maximum of 8cm (3 inches) thickness is recommended for adhesive application (so not double aluminum foil faced).PIR without aluminum facing has a thermal conductivity (WLS) of around 025-027, since the aluminum that acts as a radiant barrier is missing. When installed on ceilings and bonded with PU insulation adhesive, thermal bridges caused by mechanical fasteners are eliminated. Therefore, at the end of the day, the difference may not be significant. PIR insulation with aluminum foil facing on both sides is always specified with a WLS of 022. Without facing, the WLS increases with greater insulation thickness, so that the overall value tends to remain at 022. Why this is the case, I do not know.A
Alibert8713 Jan 2023 20:10dertill schrieb:
PIR insulation without aluminum facing has a thermal conductivity of around 0.025–0.027 W/(m·K) since the aluminum, which acts as a radiant barrier, is missing. When installed on ceilings using PU adhesive, the thermal bridges caused by mechanical fasteners are naturally eliminated. So, at the end of the day, the difference might not be that significant.
PIR with aluminum facing on both sides is always specified with a thermal conductivity of 0.022 W/(m·K). Without the facing, the thermal conductivity tends to increase as the insulation thickness grows, but overall it still averages out to 0.022. Why exactly, I don't know. Sorry if I’m bothering you, but can I omit the vapor retarder/barrier when insulating the upper floor ceiling with the aluminum-faced version?
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