using metal frame can you drop an already dropped MF ceiling

[Thorfun]

greetings. i am fitting a dropped ceiling using metal frame in my basement music room as i need relatively good soundproofing to the floor above. but i'd like to use recessed spots if possible.

 

in order to maintain the soundproofing i'm wondering if it's possible to create a dropped ceiling, plasterboard it and then drop it some more to run cables and spots in? if so, how would that be accomplished? do you simply screw the https://www.british-gypsum.com/products/metal-products/gypframe-gl9-bracket through the plasterboard back in to the metal frame and then repeat what was done before for the other dropped ceiling?

 

does that even make sense?

 

it kind of seems an expensive way to get recessed spots though but it will also assist in sound proofing as it's kind of 2 ceilings, right?

[Russell griffiths]

Could you build a plasterboard box, maybe two layers of board all glued together and insert that behind the dropped ceiling then board straight over them, then when you cut out for your spots you end up inside one of the boxes you made. 

[Thorfun]

3 minutes ago, Russell griffiths said:

Could you build a plasterboard box, maybe two layers of board all glued together and insert that behind the dropped ceiling then board straight over them, then when you cut out for your spots you end up inside one of the boxes you made. 

not sure what you mean, or rather can't visualise it.

 

nothing is currently built so i was thinking of like a service channel but a bit deeper to fit a spot light. i'll see if i can draw what i mean.

[nod]

Yes you can

Put your hangers at 800 apart 

and long enough to catch your second ceiling Put your top hat on and board round the hangers 

Then install your second ceiling using the hanger tails 

[Thorfun]

[Thorfun]

5 minutes ago, nod said:

Yes you can

Put your hangers at 800 apart 

and long enough to catch your second ceiling Put your top hat on and board round the hangers 

Then install your second ceiling using the hanger tails 

if the hangers are that long how do you board around them? surely they'll be in the way of the plasterboard?

[saveasteading]

I'd say that for certainty, you build a solid ceiling with no penetrations,  using acoustic bar, and fibreglass behind.  Then no sound will get up or down from you new acoustic enclosure.

Then you build your secondary ceiling below, again using acoustic bar, but you can inset your spots and even speakers, maybe.

 

The cheapskate chancer method would be to not build the secondary ceiling but inset  what and where  you like with an acoustic baffle behind each. There are hoods for spotlights, designed as fire barriers but with some muffling perhaps. You could attach additional sound insulation to that. Ideally you want some density too, hence @Russell griffiths plasterboard box.

 

So a plasterboard box that will slot in the void, stuffed with rockwool, and then a light with a hood on it pressed in.

[nod]

1 hour ago, Thorfun said:

if the hangers are that long how do you board around them? surely they'll be in the way of the plasterboard?

You board through them 

cut a 30 mil square on any that land on the boards Seal up with acoustic seal Don’t forget to tape and seal the joints before installling the second ceiling 

 

I do this regularly on apartment’s etc 

Its probably in Gypsum’s white book 

It will show the hangers with a bolt washer and rubber You don’t need to do this Nailed or screwed is fine 

[Thorfun]

3 hours ago, saveasteading said:

I'd say that for certainty, you build a solid ceiling with no penetrations,  using acoustic bar, and fibreglass behind.  Then no sound will get up or down from you new acoustic enclosure.

Then you build your secondary ceiling below, again using acoustic bar, but you can inset your spots and even speakers, maybe.

 

The cheapskate chancer method would be to not build the secondary ceiling but inset  what and where  you like with an acoustic baffle behind each. There are hoods for spotlights, designed as fire barriers but with some muffling perhaps. You could attach additional sound insulation to that. Ideally you want some density too, hence @Russell griffiths plasterboard box.

 

So a plasterboard box that will slot in the void, stuffed with rockwool, and then a light with a hood on it pressed in.

Ahh…..thank you! Now I know what @Russell griffiths was talking about. That makes sense and is very interesting. 
 

I could make the boxes 50mm deep and lay a 50mm layer of Rockwool around them in the void and then cover everything with another 100mm Rockwool. 
 

definitely food for thought. 

[Thorfun]

3 hours ago, nod said:

You board through them 

cut a 30 mil square on any that land on the boards Seal up with acoustic seal Don’t forget to tape and seal the joints before installling the second ceiling 

 

I do this regularly on apartment’s etc 

Its probably in Gypsum’s white book 

It will show the hangers with a bolt washer and rubber You don’t need to do this Nailed or screwed is fine 

Thank you. Will go through the white book again and have a look. 

[Thorfun]

thanks for the tip @nod. i did another search through the BG website and found this image for a secondary dropped ceiling.

 

 

so it seems that the FEA1 steel angle is screwed through the plasterboard into the MF5 channels above allowing you to to repeat the ceiling below.

 

so this will double the cost of the MF materials but give me an unbroken ceiling to reduce noise transfer above.

 

i think this is what i'll do as it also means i can fit, insulate and board the primary ceiling without worrying about running cables before hand.

[nod]

On 06/12/2024 at 21:30, Thorfun said:

Thank you. Will go through the white book again and have a look. 

It’s quite simple to set out 

No I wouldn’t do it that way Using one hanger to catch both ceilings is much stronger 

We do quite a lot like this on department stores and hotels In effect there left with a large ceiling Freshly taped with 1200 mil of hangers sticking out 
Then the shoplifters come in and do there stuff Then put a ceiling in using our hangers 

[saveasteading]

2 hours ago, nod said:

one hanger to catch both ceilings is much stronger 

Doesn't that create a sound path? The continuity of the hangers and cuts in the upper boards?

[Thorfun]

10 minutes ago, saveasteading said:

Doesn't that create a sound path? The continuity of the hangers and cuts in the upper boards?

an interesting point.

 

i spoke to BG tech support a little while ago as i couldn't find anything in the WhiteBook for what i'm after. they said that they have some internal docs they can send so i submitted a form and am awaiting those docs. that should give me various solutions and i can decide which is the best way to go.

[saveasteading]

1 hour ago, Thorfun said:

couldn't find anything in the WhiteBook for what i'm after. 

In any case, the white book and the equivalents from other manufacturers overstate the effect.

The tests were on small assemblies within a gantry in a box in a lab. i.e. better than optimum real life.

Some assemblies are estimates based on the tests.

An acoustician told me to always to take the next better assembly if these acoustic properties were essential.

 

Discontinuity is a major feature of the best performing assemblies.

[nod]

1 hour ago, saveasteading said:

Doesn't that create a sound path? The continuity of the hangers and cuts in the upper boards?

Not really 

Gypsun sell an acoustic hanger fitting if needed 

I definitely wouldn’t hang a ceiling off the bottom of the other ceiling

[Thorfun]

37 minutes ago, saveasteading said:

In any case, the white book and the equivalents from other manufacturers overstate the effect.

The tests were on small assemblies within a gantry in a box in a lab. i.e. better than optimum real life.

Some assemblies are estimates based on the tests.

An acoustician told me to always to take the next better assembly if these acoustic properties were essential.

 

Discontinuity is a major feature of the best performing assemblies.

it's not about the stated sound reduction etc it's more about building a ceiling to a manufacturer specification so that if it fails then i have a certain recourse. i'm sure i could easily make something up and it'll work but i want it to be "certified" by the manufacturer so i have someone to shout at if it all goes wrong. 😉 

[saveasteading]

49 minutes ago, Thorfun said:

someone to shout at if it all goes wrong.

Shout at me if you like. It will be equally productive. There are no guarantees.

[saveasteading]

My note about the next up spec being needed is based on a real sound test between rooms. They were as spec but all failed due to flanking sounds (corners have to touch in real life).

Fortunately the lower result happened to be acceptable in the special circumstances.

 

So it's up to you. Or pay a lot of £k to a specialist who will (over)- specify, build, test and  guarantee a result.

 

I've built a maths class next to woodwork and it was OK. Anything can be done.

[Thorfun]

Just now, saveasteading said:

My note about the next up spec being needed is based on a real sound test between rooms. They were as spec but all failed due to flanking sounds (corners have to touch in real life).

Fortunately the lower result happened to be acceptable in the special circumstances.

 

So it's up to you. Or pay a lot of £k to a specialist who will (over)- specify, build, test and  guarantee a result.

 

I've built a maths class next to woodwork and it was OK. Anything can be done.

I'm satisfied that my proposed solution will muffle the sound enough for SWMBO to be happy. obviously when i'm jamming in the music room i won't care about noise in the rest of the house! 🤣

 

i think i like to overthink things...........a lot!

[saveasteading]

1 minute ago, Thorfun said:

will muffle the sound enough for SWMBO to be happy.

And if if doesn't you can show her the white book.

Then

Reduce the bass?

Headphones instead of amps?

 

What are you jamming with? Fiddle or acoustic guitar, no problem. 

Bass guitar...hmm in your control.

Tuba.

Drum kit.

 

Bass is the likely issue, and you will need density for that.

[Thorfun]

5 minutes ago, saveasteading said:

And if if doesn't you can show her the white book.

Then

Reduce the bass?

Headphones instead of amps?

 

What are you jamming with? Fiddle or acoustic guitar, no problem. 

Bass guitar...hmm in your control.

Tuba.

Drum kit.

 

Bass is the likely issue, and you will need density for that.

full on punk rock band \m/

 

she can always goes outside and work on the landscaping.