NOISE PROBLEMS

[JAZZJIMMY]

In the summer I had new(replacement) Plastic Cladding fitted by a Specialist Cladding Contractor.
On the exterior there were four Weatherboards. All four were removed and replaced with Plastic Cladding. I will concentrate on the two large boards which were 5.5'x4.5' these were removed and replaced with Plastic Cladding. From the time the Cladding was replaced we have become aware of much external noise but in particular traffic noise.Its back to the drawing board to resolve this problem.
It was a mistake to remove the Weatherboards and replace them with Plastic Cladding but the Contractor did not advise of any negative aspects to this work.
I now realise the Weatherboards had excellent sound reduction qualities and good secondary thermal insulation qualities
From what research I have done it appears that good Sound Insulation depends on having an air gap of 2-4",with 4" being considered the optimum. I have a 3" gap behind the Exterior Plastic Cladding and Interior Plasterboard. If new Weatherboards were fitted this gap would still be available for use.
It looks as though I may be forced to buy and fit new Weatherboards but:

1) Do I have any other options? and,

2) If I do refit Weatherboards should I leave the 3" air gap or use Sound Insulation material in this space?

3) Are there any important points(eg material to be used,etc.) that need to be part of the new spec?

I would appreciate any help and guidance to avoid getting it wrong again.

 

[noseall]

is doubling up the plasterboard internally not an option?

 

[JAZZJIMMY]

I will try to think through the implications and its potential.My immediate reaction is that I think it would leave a gap at the Joists,between floors, which for Noise Insulation is critical. Many thanks for the idea.

 

[noseall]

an architect once told me that adding weight or mass to a wall can help enormously. hope this helps.

read herehttp://www.diydoctor.org.uk/projects/sound_proofing_in_the_home.htm

 

[JAZZJIMMY]

I agree mass appears to be significant when trying to reduce Noise. The Weatherboards had a depth of 1/4 to 3/8" and had that density. My research has shown that apart from the mass of the Weatherboards the airgap of 3" behind the Board was significant in producing good Sound Insulation. An airgap of 4" appears to be the optimum for Noise Insulation.

Even if I choose to revert to the Weatherboards I don't have the spec of what was there before and it would be easy to get it wrong again. I will do my best to describe what I think was there before the Cladding. Starting with the Interior Plasterboard which has an unbroken tinfoil finish facing outwards. There were a series of wooden straps(1"x 1/4"?) over the tinfoil finished Plasterboard. Then a thin Tarpaulin like material before we reach the Weatherboard. There may have been a thin board in front of or behind the Tarpaulin like material.(Behind being most likely)

Sound Insulation appears to be a very specialised field and one could easily make a mistake. The safe option is going back to the Weatherboards but even that could have pitfalls if I fail to get the design right. Experimentation would be very costly.

I would probably prefer to keep the Cladding and will continue to explore to see if solution to the Noise problem can be found.

Many thanks and much appreciation for pointing me towards the Website which I will explore.

 

[^woody^]

It is very easy to hear things differently when you are listening for them. How can you be absolutley sure that the sound levels have changed significantly? Is it the placebo effect, a trafic diversion or really significantly worse?

But you are correct in that PVCu hollow cladding can have less sound insulation qualities that timber, but solid PVCu may not be so bad.

There is no optimum air gap, and air is a relatively poor sound insulator in this context. What have you been reading?

I am a bit concerned that you say you have an airgap between the cladding and the internal plasterboard. This wall should be insulated, for both sound and heat.

I would insert 75mm of Rockwool into the gap. This will improve things no end

 

[JAZZJIMMY]

Hi Woody,
An excellent series of questions,I hope I can answer most of them.

It is very easy to hear things differently when you are listening for them. How can you be absolutley sure that the sound levels have changed significantly? Is it the placebo effect, a trafic diversion or really significantly worse?

There is a very significant and substantial difference, its as if we didn't have Double Glazing but we do.

But you are correct in that PVCu hollow cladding can have less sound insulation qualities that timber, but solid PVCu may not be so bad.

As I understand it the Plastic Cladding used on the outside of a House is quite different from that used in Double Glazing. I think I would need you to expand on this point and would appreciate it if you could give me any additional information on this issue?

There is no optimum air gap, and air is a relatively poor sound insulator in this context. What have you been reading?

This was from an earlier response I received from someone who sold sound acoustic material. It appeared to be logical because it was supported by my understanding of the airgaps used in Secondary Glazing and my own experience and understanding of how Weatherboards were used on the House prior to the new installation.(See below)

I am a bit concerned that you say you have an airgap between the cladding and the internal plasterboard. This wall should be insulated, for both sound and heat.

I think I should describe what I think was there behind the Weatherboard before the work undertaken by the Cladding Specialist. Starting with the Interior Plasterboard which has an unbroken tinfoil finish facing outwards. There were a series of wooden straps(1"x 1/4"approx) over the tinfoil finished Plasterboard. Then a thin Tarpaulin like material before we reach the Weatherboard. There may have been a thin board in front of or behind the Tarpaulin like material.(Behind being most likely)
The deep Airgaps behind the Weatherboards do not feature under the OTHER Cladding which I hope you will be able to see from a photograph and a drawing am I hoping to submit with this post.

I would insert 75mm of Rockwool into the gap. This will improve things no end.

I have no doubt that anything in the space behind where the Weatherboard had been located would improve matters but I don't want to experiment because that would be the most costly way of dealing with this issue. I think I need to get it right and that can only come with a better understanding of the Technical issues.
Did you have specific type of rockwool in mind?
Attachments.
1) Photograph of Front of House,
2) Photograph of typical Black Weatherboard on Neighbours House (Weatherboard at side and not below Window)
3) Drawing of Front of House showing Main Weatherboard locations prior to New Cladding Installation.
Regards Jazz

 

[^woody^]

There are no photo attachments!

PVCu weatherboards can come in solid or hollow profile. Solid is better for sound insulation.

The typical construction of your type of wall would have insulation inside it and not air gap - especially not one of 75mm. the installation of quilt insulation would be standard, and not experimental for you. I only suggested rockwool as it has greater sound insulation qualities than the alternative of fibreglass quilt. In any case you want the insualtion in slab form for walls, and not the roll form.

 

[JAZZJIMMY]

Hi Woody,
Twice I have left a message at the end of my last post to explain that I was unable to download the attachments from Photobucket.com possibly due to the heavy Internet Usage.I will try again to put the Photographs and Drawing on am Wednesday/Thursday.
But thanks for your valuable input.Jazz

 

[JAZZJIMMY]

Hi Woody,The Photographs and Drawing relevant to this problem-I hope. Jazz
http://i164.photobucket.com/albums/u32/JAZZJIMMY/JAZZJIMMY1/

 

[Deluks]

I can't understand why there's no insulation, you are basically paying your heating bills to warm up the air in the street outside. This 'specialist' contractor should not have replaced timber with pvcu unless doing the whole wall, so I'm assuming you now have a mixture of both on that exterior wall. I'd be getting back to them on this, unless you specified pvcu?

 

[JAZZJIMMY]

Hi Woody,

But you are correct in that PVCu hollow cladding can have less sound insulation qualities that timber, but solid PVCu may not be so bad.

When you refer to Solid PVCu am I correct in thinking that you are referring to the thickness of the Cladding used by the Contractor?Jazz

 

[JAZZJIMMY]

Hi Deluks,

I can't understand why there's no insulation, you are basically paying your heating bills to warm up the air in the street outside.

The House has always been thermally efficient and has Cavity Wall Insulation where there is double Brick and many other Insulating features.

I'd be getting back to them on this, unless you specified pvcu?

It was mainly a Like for Like replacement project with the Cladding being extended to cover where there had been Weatherboard.

This 'specialist' contractor should not have replaced timber with pvcu unless doing the whole wall, so I'm assuming you now have a mixture of both on that exterior wall.

No timber has been replaced and from the enquiries I have been making there appears to have been a(many) change/s in the building industry from what it was 30-35 years ago. The Weatherboard that was removed from the House was a compression of Glassfiber and other Materials. From the enquiries I have been making it now appears to be the case that Weatherboard is made from Timber?

What happened was that the external Plastic Cladding was replaced because it had a number of cracks.It was over 30 years old.

I hope that the photograph of the House will help you.Prior to the new Cladding there were two small and two large Weatherboards, above and between the Windows.If you look at my rather bad Drawing you will see where these Weatherboards were located.

There may well be a thermal problem relating to the cladding that has been used to replace the Weatherboards but at this time my primary concern is to eliminate the Sound problems.I think that when I have resolved the Noise problem any secondary insulation problems will also be resolved.

I am trying to undertand what was there before so that I can design and deliver the best solution.That may or may not mean going back to Weatherboards.

Hope this post gives some clarity.Jazz

 

[JAZZJIMMY]

There is no optimum air gap, and air is a relatively poor sound insulator in this context. What have you been reading?

Sound control is sometimes not easy to understand. Some things that make logical, perfectly good sense don't seem to work well in practice. Laboratory results don't always prove out in the field. Field techniques can't always be duplicated in the lab. One area of misunderstanding is wall space inside a wall. Dead air space works for you, better than filling it up with something! If you do, sometimes packing stuff in can make the sound transfer worse! A larger air space is superior to several smaller ones. This means a wall with 6" studs creating a 6" air space is superior to a wall with 4" studs and a extra layer of drywall with 1" air spacing on each side.

http://www.soundproofing.org/infopages/myths.htm

 

[jeds]

I doubt very much that this problem is caused by the difference in the density of the timber and the plastic cladding. I have seen contractors add layers of high density soundcheck plasterboard to walls to try and attenuate sound and the difference was barely measurable - so a few kgs per metre difference in density between these materials will just not show up.

You are probably getting more sound through your windows than anything else. Are your window seals in good condition? If not fit new ones. The rule of thumb is that 90% of sound travels through 10% of gaps. So it's gaps you're looking for. Find em and fill em.

It's also quite common to get road noise transferring through roof eaves vents and down through thin ceiling boards. Could the contractors have disturbed the mineral wool insulation within and near the eaves area?