Noise reduction

[Chippygeoff]

I have been offered a ground floor flat that has been specially adapted for a disabled person and will be perfect for me. However. The second bedroom would have to be my small workshop. I am seeing it for the first time tomorrow and will ask the neighbours and the one above if they can here other neighbours doing every day task. My concern is that I don't want to annoy anyone. The loudest noise will be from my router table and then my scroll saw. If I were to accept the flat I was wondering what I could do to reduce the noise. Any advice would be reatly appreciated.

 

[Drudgeon]

There are various products available for noise reduction, wall claddings, you could over board the ceiling with sound bloc plasterboard.

If It is a dedicated block of flats with concrete soffits then the sound transfer from one flat to the next wouldn't be too bad, but if it is a timber frame type construction with stud walls separating flats and floors, then realistically it would be virtually impossible to reduce the noise from a router table to a level that doesn't annoy anyone.

Having said that, if you're not using the table that frequently, and when you do, you ensure it's in the middle of the day, then I think that's about as much as you can do.

 

[blackrodd]

would it be possible to take a router or similar(noisy) item with you and, leaving it on, go upstairs and hear for yourself?
Regards Rodders

 

[Chippygeoff]

Thanks guys for you replies. The flats were built around 1960 and concrtete and black build. I have been and seen some neigghbours today and they tell me they can hear people above/below when they have the hoover pout. I will hpowever leave the router on and pop upstairs to see what it sounds like and will probably insulate the ceiling as a matter of course.

 

[jimmy_s]

noise insulation depends on the mass of the material you are using to insulate - that's why plasterboard is quite good - also any airgap that can bridge the insulating material will reduce its effectiveness (sound reduction index) substantially. A concrete floor should be pretty good if that's what's above your ceiling but if its not sealed well then you loose the benefit.

If you sheet it with another layer of plasterboard and make sure all the joints are well taped and sealed including the joints with the walls that should help. You could leave a space behind the plasterboard and line the cavity with dense rockwool slab also to attenuate any noise that got past the plasterboard - that would improve things further but the sound power level from a router is pretty high - it would be difficult to attenuate the noise to a level where its barely audible.

 

[Eric The Viking]

You could spend a lot and still have sound come through to the annoyance of others.

The biggest problem is that it's subjective - nature or God has given us tolerance to very loud noises, yet the ability to hear really small ones. You can't win, but you can do a few things that may help.

Thing #1: the frequencies involved and how they get around:

• the low pitched stuff is transmitted primarily through conduction and resonance, in effect the building's structure. The best way to reduce this is to avoid the noise-making thing coupling acoustically to the building. That means damping mats, etc. and it's hard with heavier machines.
  
• mid range and higher stuff travels mainly through air gaps, and to a lesser extent vibrates floors/ceilings. The good thing is that it's much easier to absorb than low pitched noise, so acoustic treatment(s) will always work better than for really low pitched sounds. Also look for chimneys, air ducts, gaps round pipes entering ducts and so on, anything that can provide a transmission path to other parts of the building - block and seal those, and you'd be amazed how much quieter things are.

Thing #2 the noise sources themselves:

Saws and routers consist of lumps of tungsten hitting wood at high frequencies. For example a 40-tooth SCMS blade doing 1800 RPM will thwack into the wood at 1.2kHz which is around the second D# above middle C, if memory serves. A router at 15000 RPM is lower pitched (two blades on the cutter usually). To this you add the motor noise itself, but it's all high enough in pitch to be absorbed if necessary.

If it won't make things wobbly, several layers of carpet felt (real felt, not rubber) under tyour router table will see off most structure-borne vibration. Then, if your doors seal well, and you don't have air paths to upstairs, and the ceiling/floor above is concrete, you can probably reduce a lot of the noise significantly.

But you won't entirely eliminate it. Perhaps a combination of sound treatment and bribery ("let me make you a nice...") might be the most effective.

E.

[edit - checked the pitch ]