Intermediate Floor Insulation

[youngy89]

Hi everyone!

First time posting here, but you have all been very helpful so far for me and the house renovation myself and my partner are undertaking at the moment.

Apologies if this has already been covered - but I am wondering about insulating (mainly for acoustics) an intermediate (bedroom) floor found on the first floor of our 1930's solid wall semi.

My partner is a musician and I am slowly turning the small box room of the house into a music room for her. I would like to insulate the floor however I am slightly unsure on the requirement to mitigate potential damp issues as everything I read is aimed towards the ground floor suspended floors that have air vents in the void beneath.

Our first floor buildup is typically joists with a lath and plaster ceiling directly to the underside and timber boards on top - quick sketch attached.

I have been looking at the Ecological Building Systems EcoFloor build up. This has a membrane draping up and over the joists, with infilled insulation between with a vapour control layer ontop with the timber floor boards then applied back. If I were to fully fill the space between the joists in my case would I risk condensation issues as there is no clear void beneath as the ceiling is directly beneath?

Additionally, I also have the annoyance that for about 0.5sqm of the floor has the inset porch underneath it meaning that cold air if that area is coming through quite substantially. Not sure if that changes anything...

Any help would be appreciated!

Thanks,
Tom

 

[Cubist]

Oooh... timber floor above a ceiling void that's a drum - is the lady a percussionist by any chance?

Depends on how far you're prepared to go and the cash you want/would have to expend. Almost all the effective strategies would mean a loss of height (between 20-50mm) in the room with concomitant alterations to skirtings, architraves and doors. Whilst it may be easy enough to lift the floorboards to install some sound deadening materials between the joists its also vital to then fit a series of materials that collectively isolate the floorboards from the joists. After which further materials are then laid over the floorboards after they ere fixed in place. Theres some good information on the net about the approaches and materials options and a quick search on 'SoundProofing Timber Floors' will get you a lot of useful data.

I hope she appreciates your efforts. Good luck.

 

[Flyfisher]

I don't think I can offer much specific help other than to point out that thermal insulation is a very different thing to acoustic insulation.

As a (very) amateur band member, I've played in purpose-built rehearsal rooms in various provincial recording studios (no Abbey Road for me! ) and they've all had pretty good soundproofing based on thick, dense materials. - ie concrete floors, 9-12 inch solid brick/concrete walls and 3-4 inch thick doors. They also had the usual curtains/carpets and various acoustic panels but that was mainly to dampen any reverberation and generally 'tune' the acoustics of the space as required and did little to actually reduce the noise volume. I remember seeing the plans for one studio that even had a poured concrete ceiling for sound insulation between the various rehearsal rooms.

Filling suspended floor and ceiling joists with the usual types of domestic insulation materials will undoubtedly provide good thermal insulation but don't expect much noise reduction because the room materials, ie floor and ceiling joists, any plasterboard or lath&plaster walling or ceilings etc, will still vibrate with the sound and transmit that sound to anything connected to them (as per Cubist's 'drum' analogy).

I guess much depends on the noise level to be contained and the attenuation required but I'd not expect too much just from filling a few voids with something akin to rockwool - except a warmer room of course.

 

[youngy89]

Thanks for the feedback so far.

Yeah, I know I would need a crazy amount of build up to truly get a sound insulated room - especially in a suspended timber floor. Fortunately my partner is a guitarist and singer, so no percussion instrument - she also understands that it won’t be completely silent through the walls. But we are just doing what we can.

If for a moment we forget I mentioned acoustic, and focussed on thermal insulation - do you foresee any issues about full filling the space between the joists with regards to condensation given there is no clear void under the joists due to the ceiling and no air vents etc. Do you think if I follow the same principles as what would on a typical ground floor installation I will be ok?

Cheers!

 

[lizziecupcakes]

Do you have a garden? If so, is it big enough to build a space for this?

 

[paulc]

I don't think I can offer much specific help other than to point out that thermal insulation is a very different thing to acoustic insulation.

I guess much depends on the noise level to be contained and the attenuation required but I'd not expect too much just from filling a few voids with something akin to rockwool - except a warmer room of course.

Having stuffed the void between ceiling and upper floor, I can confirm that it makes very little difference in terms of noise transmission. A thick carpet along with a decent underlay in the "music room" will help to absorb some of the noise. Having said that, filling the void above the porch will certainly reduce heat loss, so concentrate on that area.