Insulation between floors

Dec 14, 2010 4 Replies

From some googling and reading around this seems to be a subject where there are differing opinions, or at least where the right approach depends on lots of different factors so I'm posting here to see what the group think.



I'm currently "redecorating" a couple of rooms, one ground floor, the other 1st floor immediately above. There is currently no insulation between the two floors. I'm wondering whether it would be a sensible idea to fit some, either to keep heat downstairs or to reduce noise.



More details ...



It's an old stone built building, with solid external walls about 1.5 foot thick on 2.5 sides. The other walls are the same, although (now) internal. The floor is solid - tiles presumably onto the ground given the age (around 300 years), with I'm guessing no insulation :-).



In both rooms I'm fitting insulation and vapour barrier backed plasterboard on battens to the 3 walls which make up the 2.5 external walls. Regular plasterboard on the other walls. Both rooms have smallish new wooden double glazed windows. Currently no insulation in the loft, but I?ll be adding some.



The upstairs room will be decent thick carpet on decent underlay, on top of 22mm T&G chipboard. The space between the joists is currently empty. The ceiling below will be two layers of plasterboard, 12.5mm on top of, probably, 9mm. Floor in the downstairs room will be similarly decent carpet and decent underlay.



Heating will be radiators in both rooms, and an occasional wood fired stove downstairs. Downstairs will be a sitting room and upstairs a child's bedroom.



So given the above it is sensible to fit insulation either to keep heat downstairs, or to stop noise in either direction? I don?t have a good feel for whether it can make a big difference in either case.


sound insulation is not the same as heat insulation.

Unless the rooms are expected to be at markedly different temperatures its a waste of time doing thermal insulation

Sound insulation OTOH has its uses, and is better done by a thin layer of pea shingle then sand - but emphasis on thin there, no more than one litle piece of stone deep, and with the sand a few mm will suffice, more will only find its way out through cracks. These add mass and damping. There are several other options too.

NT

Is open onto the outside walls or are you extending the internal insulation across the floor void as well? If the latter not much point in insulating the void as it's inside the main "thermal box", how ever if it's open to the external walls and the void between the internal insulation then doing something about insulation their is probablya good idea.

When this place gets gutted the internal insulation will cover all the inside area of the external walls forming one large "thermal box", penetrated only by windows, doors and joists, all of which will draft proof.

Good pot. I have awful sound leakage between two rooms one above the other, because the floor and ceiling, to wall, joints are not sealed. For reasons I won't go into here..

The FIST step in sound reduction is no air gaps.

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