Noise insulation.

[Tim Lamb]

I know this has been done before....

We have a door in what was an exterior cavity wall giving access to an annexe and our lodger. There is a separate exterior door so the internal one is currently only used by the cleaner.

The adjoining room is used as a bedroom on the occasions when all the family are home. The lodger is a pilot so tends to disturb sleepers when leaving for an early flight.

My family seem convinced the only solution is close off the opening with fresh block work. So far my efforts have not gone beyond adding draught seal to minimise airborne transmission. The door is double skinned, pine and oak for fire resistance so quite substantial. The wall continues to the roof apex so this is not loft transmission.

My question is.... would fitting a second similarly constructed door to the other side of the opening give significant further attenuation? Or??

[tabbypurr]

A good clear pic would help. A 2nd door should make a difference. So could lining them with the better sound absorbing materials, eg viscoelastic polymer & PB.

Doors etc transmit sound at resonance, its best to make the 2nd one with a different resonant frequency.

NT

[Tim Lamb]

Er.. 11" cavity wall with door hung flush with one side. Door has one side cheap ledged and braced pine the other tongue and groove 20mm oak.

I have a spare pine door (skip diving:-) and plenty of oak to plane up.

Yes. As the inside will not be visible, I suppose quilting or tacked on underlay might suffice.

[Mark Allread]

Will the cleaner contine to use the internal access door? If not, in addition to the quilting could you not fill the gap between the two doors with insulation to further assist in sound reduction? Easily removed once the lodger has gone and you want to revert to a proper doorway again

- certainly less permanent than building the gap up with blockwork!

[Dave Plowman (News)]

Yes. Sound studios all have such double doors. Although of course to also allow people to go in and out with the minimum of external noise let in.

But if there's, say, a band playing it is obvious the second door helps as you go from outside to inside.

Both doors need to be well sealed. And as heavy as possible.

[Tim Lamb]

The cleaner will still need access. Partly to maintain the *lodger* as opposed to *tenant* status and partly convenience. Saves lugging her Hetty out of the back door and across the yard.

[Tim Lamb]

In message , "Dave Plowman (News)" writes

OK chaps. Decision made. For the cost of a set of door stops, hinges and latch gear plus a bit of labour I'll get on and do it.

>

[tabbypurr]

For weight, you're better off with sand than wood. Sand has more damping.

NT

[Tim Lamb]

The ideal stuff would be the filled rubber sheeting intended for vibration damping on machine tools.

I'll see how doubling the doors goes and worry about adding mass if it is not sufficient.