Resilient bars fitted correctly??

[Omnibuswoman]

In an effort to move forward more swiftly I have hired in a local chap (retired ceiling fitter) to help with plasterboarding the ceilings. 
 

So far I’ve been underwhelmed with his fairly messy work (favourite phrase “that’s what plasterers are for”). Today he fitted resilient bars and they are touching the wall in places (see photos). Is this still ok (as he tried to assure me it was) or should I move them? 

[Nickfromwales]

39 minutes ago, Omnibuswoman said:

In an effort to move forward more swiftly I have hired in a local chap (retired ceiling fitter) to help with plasterboarding the ceilings. 
 

So far I’ve been underwhelmed with his fairly messy work (favourite phrase “that’s what plasterers are for”). Today he fitted resilient bars and they are touching the wall in places (see photos). Is this still ok (as he tried to assure me it was) or should I move them? 

Looks ok / good to me, but I am a stickler so always tell my guys to put 2 screws into each joist as I'm not a fan of these only having one screw in them.

 

The bars at the outside walls are fine; at the end of the day the walls don't move, so where the ceilings meet walls, get scrim taped, and get plastered, you won't actually want any movement there as the plaster / paint would crack. 

[Omnibuswoman]

Thanks Nick. So in terms of noise transfer, the wall contact isn’t an issue?

[Nickfromwales]

@Omnibuswoman

 

I hasten to add, the old boy should be marking the posi joists on the plasterboard so zero screws go into these. Using 25mm screws is very good 'buffoon insurance', but the moral is to ONLY be screwing the PB into loose RB and NOT into the posi joists as the PB will then want to keep pulling up and pinch the RB tight, the opposite of what you want.

 

Have this chat before he fits a single PB, and TELL HIM what you want. 

[Nickfromwales]

Just now, Omnibuswoman said:

Thanks Nick. So in terms of noise transfer, the wall contact isn’t an issue?

Nope. You get the benefit of the central area of ceiling being 'suspended', but at perimeters the walls and ceilings become one connected mass by default.

[saveasteading]

4 minutes ago, Omnibuswoman said:

in terms of noise transfer

As nick says. But if the spec says 1 screw then that is what you should do but only with very good screws with enough thread.

Why?

The rb works by minimising direct contact. What there is, is offset by that loose-hanging Z of the bar. So when it vibrates it is a wibbly wobbly reaction rather than direct and in phase.

 

 

[Omnibuswoman]

Thanks. The ceiling will be double boarded so it is important he knows where the joists are. Or if I bin him I need to know where they are!

[Nickfromwales]

2 minutes ago, Omnibuswoman said:

Thanks. The ceiling will be double boarded so it is important he knows where the joists are. Or if I bin him I need to know where they are!

If double-boarded and skimmed, there will be a huge amount of weight on those single drywall screws. First thing to do is speak to the manufacturer and ask what is required here.

 

I'd be putting 2 screws in at each point of 'suspension', which will have zero negatives and a lot of positives.

 

4 minutes ago, saveasteading said:

But if the spec says 1 screw then that is what you should do but only with very good screws with enough thread.

You think old boy Roy read the specs??  

[Nickfromwales]

6 minutes ago, Omnibuswoman said:

Thanks. The ceiling will be double boarded so it is important he knows where the joists are. Or if I bin him I need to know where they are!

Mark them on the walls, or get a tape out and start noting datums and spacings etc.

[Omnibuswoman]

Given how few boards he got up today I will just take them back off tomorrow, double up the screws, and refit the boards. Then will start looking for a replacement boarder…

[saveasteading]

Resilient bar has always worked well in practice.

If any noise gets through it will be flanking sound, coming between the wall and ceiling interfaces, so follow details.

[saveasteading]

20 minutes ago, Nickfromwales said:

huge amount of weight on those single drywall screws. 

I'm thinking of the rb to joist connection. It is timber so needs a timber screw and I hadn't considered they might use a drywall screw.

[Nickfromwales]

4 minutes ago, Omnibuswoman said:

Given how few boards he got up today I will just take them back off tomorrow, double up the screws, and refit the boards. Then will start looking for a replacement boarder…

Maybe don't hang around the bus depot or retirement homes    

[Nickfromwales]

Just now, saveasteading said:

I'm thinking of the rb to joist connection. It is timber so needs a timber screw and I hadn't considered they might use a drywall screw.

They all do, as they're useless lazy twats. Drywall screws are brittle as feck, and shouldn't be used for these loads.

[Omnibuswoman]

This just made me think - I think he used drywall screws to fix battens to the ceiling upstairs. Does that need to be redone too?

[Nickfromwales]

5 minutes ago, Omnibuswoman said:

This just made me think - I think he used drywall screws to fix battens to the ceiling upstairs. Does that need to be redone too?

They are brittle and have far less tolerance to snapping, vs regular wood screws. If he put plenty in then I think you'd be Ok, but if few and far between, then it could be a problem.

 

Are these still exposed? If so, just pump a woodscrew in next to each one.

[Omnibuswoman]

Sadly not… the boards went up so I will need to take them down and add in the woodscrews 🙄. At least I haven’t paid him yet… that isn’t going to happen now. 

[Nickfromwales]

2 hours ago, Omnibuswoman said:

Sadly not… the boards went up so I will need to take them down and add in the woodscrews 🙄. At least I haven’t paid him yet… that isn’t going to happen now. 

Sounds like you should have done the job first as last lol!

 

Get a friend or two around and crack on 🙃.

 

I once asked the plaster-boarders apprentice, why are you using the wrong length screws (using 55mm when I had requested they used 32mm MAX to avoid all my LED multicore flex’s in the swimming pool walks)….. He replied that “these were already on site”. 
 

After plaster and paint we fired up the LED’s and POOF! Found a screw right through 2 of my 5-core cables for the RGBW stuff. Cheers. 
 

Only took about 3 days worth of looking / fault-finding at a cost of ~£2k to the client. Then began the patching back in and fully repainting the walls etc.

 

Why are people generally just such lazy dicks???

[SteamyTea]

Resilience bars are just springs (simple harmonic motion rules).  One end should be fitted solidly to the wall/stud/whatever, while the other end is free to move, unhindered.

If the free end (the side the plasterboard screws to) is rubbing against the wall, then there is unnecessary friction, this needs to be avoided.

So I would take it all down, move the bars a few millimetres, and reattach the plasterboard.

 

As you are double boarding, are your resilience bars rated for the extra load?

To use an automotive analogy, imagine you are driving over a speed bump and your front suspension bottoms out, then you run over a brick, your suspension has used up all its travel, so all the loads are now transmitted directly to the bodywork.  Basically, you have no suspension or damping.

 

[Omnibuswoman]

Thanks @SteamyTea. I hadn’t been aware that the bars differed for double a board load, so I don’t know whether the ones I got are suitable. I will now check!!

[saveasteading]

24 minutes ago, SteamyTea said:

and reattach the plasterboard.

 

But then the plasterboard must touch and be sealed at the interface. It's a compromise.

I think you are OK unless it is a recording studio, or a bedroom under a gymn.

[Omnibuswoman]

The room is a guest bedroom and above it is an open plan kitchen diner with solid floor surface (or it will be once it is finished) so the main thing is stopping HWMBO’s clod-hopping from waking our lovely visitors. I will use acoustic sealant around the perimeter. 

[SteamyTea]

6 minutes ago, saveasteading said:

I think you are OK unless it is a recording studio, or a bedroom under a gymn.

Yes.

It does depend on what the aim is.

Noise is just a change in air pressure, which is usually short term in a house (you can unplug the TV/PCs and Stereos).

Living next to a very busy road, on a hill, by a roundabout, is very different from dealing with strange noises from a bathroom. 

[SteamyTea]

1 minute ago, Omnibuswoman said:

open plan kitchen diner with solid floor surface

You can add some sound deadening between the floor and joists.  In effect, a resilience bar.

Be interesting how resilience bars works for a floor, it is more normally rubber strips.