Sound proofing utility room ceiling void

[brewdexta]

Now that we've extended the utility up a floor expand the youngest's bedroom, I need to sound proof the utility ceiling so she can't hear the washer and dryer much.

Now I have the floor down and have sealed up all the gaps, noise loves finding gaps, it is much muted but still audible. The floor will have an inch of polystyrene underfloor heating matting and then 22mm of oak flooring so likely to deaden even more but to make sure I was thinking of filling the utility ceiling void with Rockwool RWA45 acoustic insulation slab. Area is 11m2 so although expensive stuff it's worth it.

I'm using acoustic compliant downlighters in the ceiling to help seal the noise, but I don't think I need to go the whole hog and use acoustic plasterboard. The washing machine is a Miele so doesn't make a racket like some do, it's mainly the dryer but it's on its last legs and the next one will be a bit quieter.

I haven't used the Rockwool acoustic insulation slab before, is it easy to carve around pipes and cables running through the joists? I was thinking of getting some 100mm and 50mm thick to fill the 150mm void and aid getting it above/below the services.

Cheers
Andy

 

[eLuSiVeMiTe]

Easy to cut. Think very compressed loft insulation. Old handsaw does the job.
Can rip by hand if needs be or good sharp scissors

Put in hundreds of sqm over the years. Works well.

 

[knighty]

can you loose some height in the utility ceiling?

if you put the insulation boards straight over the joists and then fix the ceiling to/through them you'll add a cushion between the ceiling/joists so cut down on sound transmission?

 

[brewdexta]

I think the noise will still be transmitted from the boards through the fixings but I think I don't I need to go that far, she will be making plenty of noise herself

 

[armalites]

Have you about sheeps wool insulation? Good accustic and thermal qualities also works well in the presence of moisture as it breathes. It's nice to work with and environmentally friendly.

 

[Burdekin]

I've used products from these guys before: http://www.customaudiodesigns.co.uk/products.htm would give them a call. Options are to block the sound buy adding a dense barrier or absorb the sound or both.

 

[clift_d]

You are making life harder for yourself by using recessed downlighters, as you are making holes in the ceiling for sound to travel through. It would be much better to use some kind of surface mounted light fitting instead and aim for an unbroken sealed ceiling.

If you can change the lights then the easiest thing would probably be to use a double layer of wallboard for the Utility Room ceiling, with 100mm of Rockwool above between the joists. If you really want belt and braces then fix resilient battens to the ceiling joists and fix the wallboard to those, again with the Rockwool above. As above, it will be important to make sure that the ceiling is properly sealed at the edge to the walls.

You might also want to consider putting the washer and dryer on resilient footings.

 

[eLuSiVeMiTe]

can you loose some height in the utility ceiling?

if you put the insulation boards straight over the joists and then fix the ceiling to/through them you'll add a cushion between the ceiling/joists so cut down on sound transmission?

Accustic flooring works well for that. No fixings just floats on exsisting floor with a barrier between.

 

[addjunkie]

Wash when shes at school, and dry on the line on the 4 fine days you get in them there hills!

Put rubber cups under washer and dryer feet, vibration transfers sound

 

[Shox Dr]

Lots of insulation, then insolate the flooring from the joists, and walls. Making sure there are no air gaps. Neoprene works well.

 

[Farside]

The Victorians sussed that mass deadens noise. The better class of Victorian tenements had ash and clinker in the floor joist spacing, to a depth of around 2 or 3" iirc.
It was amazingly effective when done right, and many later owner occupiers found that removing the clinker restored the noise from the sods underneath.
Since you already have the floor down, I don't suppose you feel like lifting it up to do this, but a heavy layer of plasterboard on the ceiling will go some way to accomplishing the same, if not totally. Perhaps plasterboard / heavy rubber foam composite might be the thing.

 

[maz0]

This chappy does a great video comparing various materials for sound absorption. Long story short a bunch of towels were far superior than the grossly overpriced acoustic foam sold online. I imagine a nice big thick layer or two of glass wool might have the same effect?


[yt]

 

[123hotchef]

I used the acoustic rock wall and acoustic plaster board both great stuff I even double boarded the dividing wall between us and the neighbors after studding it and filling with the rockwool. I must say the sound board is great stuff heavy as fook it is twice the weight of a regular sheet but well worth the investment if you ask me oh and I think I used the 15mm I could be wrong it was 4 years ago

 

[slim_boy_fat]

Stuff the void with egg boxes? coat > door