insulation under ply floor with travertine tiles

[Loz7]

I have 6x2 joists with 18mm ply and travertine tiles on top, I want to put 100mm rockwool in between the joists does there need to be ventilation for the 50mm gap above? or I could put 150mm celotex and glue it to the underside of the ply?




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See also
https://www.diynot.com/diy/threads/...-floor-with-tiles-on-top.493451/#post-4041751

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[endecotp]

Whatever insulation you use, push it up against the ply. No 50mm gap.
Easiest is to fill the 150mm with rockwool or similar.

 

[John D v2.0]

Is this a ground floor or first floor? Assuming ground floor, as above, rock wool is a lot cheaper so go for 150mm. Make sure no air can move between the insulation and plywood.

 

[Doggit]

Assuming you've got access to the underside of the floor, you'll need to use netting to hold the rockwool in place, and you can staple it as you go. 100mm rockwool may well drop over time, so use 170 instead. But to be honest, this won't achieve a great deal, as the Travertine is always going to be cold.