# Sound Insulation For Workshop



## littleplop (31 Jan 2022)

Hi Everyone,

New member here and I expect to be visiting a lot as this looks like a great resource.

Initially I just have a hopefully simple question with upgrading my boat building workshop.

It is built on the concrete pad behind my garage and is 6.6m long and 2.1m (inside measurements).

The wall frame is all pressure treated chunky C16 wood and is basically a sandwich of 11mm OSB on the outside and inside - see attached





and is orientated that way to maximise the very narrow width.

On the outside of this long wall is Onduline roofing sheets which has "built in ventilation" with the curvy shape.

It is butted up against the next door fence and is therefore massively protected and the prevailing weather is from the other side anyway.

Both ends are the same 11mm OSB sandwich but as I have access to this I have now replaced with shiplap dyed black and have double doors made of the same OSB sandwich with the shiplap which looks great.

The roofing is very chunky rafters with 18mm OSB:





This has a membrane on it then it has more of the Onduline sheets.

The highest end of the roof butts on to the back of my oak framed double garage which has massive feather edge boards and is all cut into it and bolted into the framework very strongly.

All the walls frames are sat on a damp proof membrane on the concrete and bolted into it.

My main question is now I can see the empty gaps in the walls and roof and want to put something to help minimise any noise for the neighbours.

It is not heated and will never be as I'm always hot.

So, I'm wondering whether something like Rockwool RWA45 ROCKWOOL RWA45 Acoustic Sound Insulation Slab 100mm Thick - 2.88m2 Pack | Roofing Superstore® would be any good up in the roof?

Will it need an air gap to the outer OSB?

I can drill some vent holes through the noggins to keep some airflow.

The apex is not sealed to the garage wall - there is a flashing but it is not air tight.

The same thing for the walls then as well - very narrow with basically a 40mm gap.

Can I put RWA 45 in there? Will it need a gap?

I can do the same with any vent holes if required.

Otherwise, anyone any thoughts on what I can do or is it so narrow as to not be worth the bother do you think?

I have great neighbours but don't want to water them off with a CNC machine running cutting out the kits for the boats once the protype has been built this spring.

Any and all thoughts gratefully received!


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## thetyreman (31 Jan 2022)

what you will find is rockwool only attenuates at most 6dB which isn't really a lot, you would need to use mass layer vinyl and also seal it up airtight with acoustic caulk if you are serious about stopping the sound from getting out, and it isn't cheap, any big gaps use backer rod and acoustic caulk to fill it in, seal it airtight.


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## Jameshow (31 Jan 2022)

I think the rockwool is a good idea 

Also put an inner layer of OSB ply plasterboard but separate it from the frame using laminate flooring underlay. That way any sound isn't bounced through the wall via the studs.... 

What boats are you making interesting?!


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## thetyreman (31 Jan 2022)

fibreglass is just as good as rockwool cheaper and performs better acoustically, the fluffy stuff they use in lofts


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## Jones (31 Jan 2022)

Firstly block all gaps under eaves etc, think how much difference shutting a door can make to any noise. Stopping airborne sound is basically about mass to absorb it and insulation doesn't have much ,though two layers of OSB is probably quite good. How noisy is your machinery, the manuals should give you a dB rating? You may find you don't need to do anything other than block gaps.


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## Kriggi (1 Feb 2022)

Use Rockwool RW3 if you can over the standard loft insulation stuff. RW3 is designed to be an acoustic insulation and will be far more effective, has more mass (60kg per cubic meter). Just don't buy it from an acoustic supplier, they'll rip you off. I bought an 8 pack of 600x1200x50mm last week for £33.45 inc VAT from Encon insulation. Picked it up myself though so no delivery charge.


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## littleplop (1 Feb 2022)

Thanks everyone for the speedy replies, I will investigate further.

I guess a key thing for me to understand is whether I need to keep airflow on the inside of the out OSB skin or just completely fill it?

As the workshop won't be heated and there will always be small gaps around doors and so on I was assuming it would be fine as sealed up tight as possible with spray foam in all the joints etc. It also connects into my other main unheated double garage plus workshop so there is a reasonable amount of airflow in general.

The noisy machines will be mainly a circular saw mounted in a new cutting table, routers (which really make a racket) and I'll be getting a CNC machine but looking at getting spindle not a router for it and then ensuring it is as enclosed as possible.

I've designed and made various small boats mainly based around trimarans as they just really appeal to me!

I started by building a 22 ft double sea kayak that I then converted and powered up into a sailing trimaran:




Loving the sailing I started investigating a more powered up pure version doing some comedy botching an outrigger to an old ISO dinghy:

to get a feel for more power.

This then lead to the Adventure 600 folding, trailerable hydrofoiling trimaran here not foiling:




and here a folded out view on the trailer of the rear inverted T foil:




and here folded showing the front L foils:





The latest design is a 6m RowSailer which will have shorter floats and easily launched, sailed and handled by one person as it should come in around 100kg.

It will have a large balanced Lug sail for the main and a smaller lug sail for a mizzen to balance it up and the floats will fold backwards for storage and trailering.





The blue area is a micro cabin for overnighting and I'll have a tent that will also cover the hatch and go back to the rear storage area.

My plan is to set up a long adventure race along the south coast - a coupleof version ranging from 100-300 miles to be done over the course of long weekends/a week. Tentatively called SCAR (the South Coast Adventure Race) as you are bound to pick up a few...

I need to get building this as soon as the shed is fully usable so I can get testing it this summer (in amongst thrashing the A600 which is really a full on mental machine).

Once protyped I'll be offering plans for the RowSailer as well as the A600 and also CNC cut kits and partial builds in wood for people to finish off.


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## Jones (1 Feb 2022)

You can totally fill between studs and joists but should have a vapour barrier on the warm side ( inside). OSB counts as a vapour barrier as it is basically impermeable, you could mastic the joints to be sure. The simpleist way to reduce machine noise leaking outside is to ensure there's no direct paths such as holes,vents, open doors etc. Also if possible schedule the noisy times for when the neighbours are out. While adding insulation will make a small difference adding mass in the form of heavy sound insulating plasterboard or just thicker OSB will probably do more. The roof is probably less of an issue as no one lives above the shed and sound is quite directional . My advice would be assess how much of a problem there is before spending lots you can always add pb or osb to the inside later. Nice looking boats


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## thetyreman (1 Feb 2022)

don't confuse acoustic treatment with sound isolation, rockwool will do almost nothing to stop 100+dB noise from leaking out, at best it'll attenuate 6dB making it 94dB SPL, still very loud, with a layer of OSB that will bring it down a bit, but you'll be mostly wasting your time and money if you don't seal up every gap in the walls, something like everbuild AC95. Sound is like water, even the tiniest gap will leak out, so the importance or airtightness can't be overstated enough.


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## littleplop (1 Feb 2022)

Jones said:


> Nice looking boats



Thanks very much!

I think I'll just get the inside skinned for now and get it usable and then revisit the possible sound proofing once I am functional.

Just sorting roof today, the first of the doors and the storage in the rafters so I can get some rubbish off the floor!


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## Jameshow (1 Feb 2022)

littleplop said:


> Thanks everyone for the speedy replies, I will investigate further.
> 
> I guess a key thing for me to understand is whether I need to keep airflow on the inside of the out OSB skin or just completely fill it?
> 
> ...



Nice boats rather like the raid events?


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## littleplop (1 Feb 2022)

Yes exactly - Texas 200, Everglades Challenge, Race To Alaska etc.

Starting to plan various options for the SCAR - A basic round the Island and back starting from say Poole or Weymouth would be good intro.

Another one could involve going round Hayling Island and IoW but having to go under the Hayling bridge will limit beach cats. They could perhaps have to go to each side of the bridge ie round Hayling twice.

Other years, start from Brighton or Hastings so there is some variety.

The RowSailer should be ideal for this sort of event being stable, light, fast and safe with plenty of storage and the small enclosed cabin. For shorter, faster day trips the A600 is better as it quite literally flies along, but is a fairly challenging boat to sail as the wind steps up.


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