Dear Acousticians
I would like to ask for some advice about low profile solutions in a scenario in which there is not much space to lose. From what I've read there seems to be a depth of knowledge that I have not found on DIY forums.
I live on the second floor of a 5 story block of flats in central London built circa 1920 and suffer from noise coming from all directions, driving me to distraction.
The flat has red brick walls throughout and concrete and beam ceilings. That is, reinforced concrete beams and "clinker" blocks in between, which is a sort of cheap concrete aggregate. The floors are made of the same thing with a cement screed, although the communal landing might be solid concrete.
There is a lot of foot traffic up and down the stairs often throughout the night, and because of the number of student rentals I am awoken by the thunder of trolley suitcases, high heels and shouting. Next doors front door adjoins my bedroom wall and window. I can hear voices clearly from upstairs, as well as TV and to a footsteps if they are wearing shoes (they have cursed laminate floors).
Sound flanks from flats below, and from the slamming of the main entrance up the walls. I have researched all the materials available and am aware of the main methods used in domestic soundproofing. The biggest problem I have is that because of the small size of the flat, I can't go nuts and batten the whole flat out because I'll end up living in a shoe box!
In order to reclaim space from the walls I plan to have the render, which varies from 15-20mm thick, stripped back to the brickwork.
My basic plan is to focus on the bedroom, batten the external walls and possibly the flaking walls, but go direct to brick around the rest of the room. I plan to try and use cheaper materials in the living room walls if possible.
I have looked at a number of sound insulating panels and have identified the Maxiboard and Phonewell panel as two dense yet thin solutions, although only the Phonewell is recommended as a remidial solution for "failed" walls which need to be retrofitted. There are other panels like M20, JCW silentboard and Gyproc Triline but they are all quite thick, or made from cheap materials and/or overpriced.
Google "soundreduction.co.uk/Products/Walls/Maxiboard-For-Walls/"
Google "acaraconcepts.com/"
The Phonewell panel (Acara Concepts) looks very versatile, made from compressed sand, and can be laid as a floating floor, stuck to brick using industrial strength foam adhesive, and used with resilient bars for best results. This is probably the panel I will use.
Can anybody report their experiences using these materials?
For the ceiling I plan to use resilient bars. At first I thought they could be attached straight to the ceiling, but I've been told not to use them this way, to at least use thin timber strips as "packing" to decouple the bars from the ceiling. I am told that the resi bars are all more or less similar and can hold about 35kg/m, how close should I load the bars to this figure? Given the weight of the panels they will be spaced at 400mm centres. I am also looking at resilient bar and clip system. The panels would be attached to the bars and then finished with blue plasterboard.
Google "hush.uk.com/sound-control-products/hush-bar-plus.php?id=1"
The trouble I am having is in knowing what will work, even moderately well given the materials my flat is built from, and the method I wish to use. I have come to realise that the figures used to advertise these products can be confusing, and are not to be taken as standalone figures representing reduction in terms of dB, but used in combination with the exact configuration used in the labs. In other words, I wont know till I have spent 1000s.
It would help if someone could comment on the solution I have proposed, and perhaps explain:
1. When a soundproofing panel is "rated at 43dB", how am I to know what sounds it will and wont cut out and by what degree, i.e. what sounds commonly fall within the spectrum of frequencies, I think voices/TV and mid high and footsteps low?
2. I am aware that sound for soundproofing purposes is divided into the impact and airborne type, that one is solved by mass and the other by airspace, but am not clear which solution applies to which type of noise.
3. How important is the size of the airspace for blocking the sounds I have described, in particular coming from the ceiling. I am told that maximum decoupling is more important rather than depth. I have also been told that sound can actually amplify if it reverberates within the cavity, so some soft of lightweight material should be used to stop this, like foam? If I was using resi bars to a depth of 25mm, that would be the minimum thickness of acoustic mineral wool and I would lose out on the air gap, plus all the materials would create a bridge. I suggested cutting the material down to 10mm thick but I was told this wouldn't be worth it.
4. How effective do you think it would be to stick a sandwich of blue plasterboard and mass loaded vinyl to the walls, with gaps top and bottom, to stop flanking and some airborne sound. What thickness of panel could I get away with? Would you recommend greenglue over rubber membrane?
5. Any tips for retrofitting my front door to reduce sound through there, e.g. can I load mass onto the back of the door.
Please let me know if there are any other products you recommend and thanks to you all for reading!