Soundproofing a party wall without losing too much space.

I'd like to soundproof the party wall in my lounge, but the problem is the front window recess starts a mere 50mm from the party wall, ergo putting in a new detached stud wall is out of the picture.

I'm also on a budget!

What I had in mind was to first put in some 37mm x 6mm deep timber battens against the party wall and plasterboard across the front. The gap would be infilled with fibreboard underlay glued to the wall (supposed to give sound & thermal insulation plus I already have a load left over from a laminate floor install at my last house)

This should give me some limited decoupling by reducing the contact patches for sound transmission. I'm even considering pre-drilling screwholes in the plasterboard and gluing a couple of washers to the underside to decrease the contact patch even more.

The plasterboard itself would be two skins of 12.5mm acoustic plasterboard bonded together with green glue - apparently this stuff is great but not overly cheap, hence why I'm attempting decoupling rather than green glueing both layers of plasterboard right onto the wall.


Opinions, alternatives or suggestions most welcome!

Ricardus said:

I'm also on a budget!

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Fine, do all that you thought and suggested....just don't expect miracles.

If you have limited space then this is well worth investigating www.greengluecompany.com

My son in one house ripped off the plaster and replaced it with laths insulation and special sound resisting plaster board and the results were astounding.

He did it to stop his sound getting to next door but also worked in reverse.

As to if it was insulation or the type of board I don't know but it did work.

ericmark said:

My son in one house ripped off the plaster and replaced it with laths insulation

Click to expand...

Where do you buy this "laths insulation"?

Actually I was looking for up to date reviews of the Green Glue system when I found some info about decoupling and air gaps and the triple leaf problem. Basically bigger the air gap better, and anything less than 50mm you run the risk of creating a resonant zone that will actually increase the transmission of certain frequencies, so my 6mm decoupled wall ideal is probably going to be a lot of work for nothing.

However further research turned up 20mm thick recycled rubber matting under various trade names that you glue to the wall then glue a double skin of plasterboard over the top of.
It looks promising especially if I were to use acoustic pb and green glue to face it.

I believe the heavy rubber is more effective if it has no contact with the wall - hanging like a curtain. Failing that, glue it to a layer of open-cell foam. I used this method on a car that I rebuilt with an aluminium gearbox cover. It was horrendously noisy without it.

Many years ago a company (Dunlop?) developed a system that used a lead powder filled flexible membrane glued to an open-cell foam layer. It was thin and very effective. The weight and flexibility were important. Unfortunately, it was extremely expensive.

You could also use sheet lead like the lead flashing that they use on roofs and hold it in place with board. I Googled "lead sheet" and found this:-

http://www.midlandlead.co.uk/products/soundproofing.html

Well, to resurrect my old thread, I finally did the soundproofing.
First, I took off the old render/plaster from the wall which gave me 62mm depth on average between the wall and the edge of the window recess. I then installed 38w x 19d wood battens vertically, with foil bubble wrap insulation across the front to provide thermal and electrical insulation. I relocated the 2gang electrical socket to the side of the chimney breast so I wouldnt have a hole in the new plasterboard wall.
6x resilient bars went across the top of the battens & foil with about half the mounting screws going through the batten into the wall beneath.
12.5mm soundblock plasterboard was put over the top with a 2-3mm gap around the edges which was sealed with AC50 acoustic sealant as were the joints between the plasterboard sheets. I used 3.5x25mm plasterboard screws for the first layer, checked for bounce and in a few cases took the screw out again and chopped the tip off with pliers to prevent shorts. A 2mm HSS drill came in handy to pilot the holes in the resilient bar.
The second layer of 12.5mm soundblock went up with the joints staggered and about a tube to a tube and a quarter of Green Glue applied to the back of each panel. 3.5x32mm drywall screws this time and again, a few with the tips chopped off after failing the bounce test. More AC50 around the edges, joints and in any empty screw holes.

I left the plastering to a professional, who gave me an odd look when I asked him to leave a 2-3mm gap around all the edges and I had to explain to him a couple of times that the wall needed to flex before he got what I was on about. Once the plaster had dried out I resealed the gaps with AC50.

My original problem of the 50mm gap almost resurfaced as the depth of the resilient bar isn't exactly consistent, especially not after you've pushed and pulled it around when putting it up, and the end result left the outer face of the PB overlapping the window recess by about 5mm at the bottom - the recess wasnt perfectly straight and true but the plasterer put in a couple of stop edge beads to maintain the floating wall and plastered it level no problems without overlapping the window frame.

Of course the sound can still travel through the ceiling, and in lieu of re-boarding it with resilient bars etc I compromised by lifting a couple of floorboards and filling the void nearest the wall with RB5 Rockwool slabs.

Now all that remains is to replace the ceiling coving and skirting board, remembering to only attach the coving and skirting on one edge. And replace the double doors between lounge and diner with something a little more solid. B&Q are doing double glazed rear doors for under £100 each

For a 4.5m wall including a chimney breast I budgeted around £500 (excluding plastering), and I've gone about £50 over but that includes buying some extra shiny sockets and grid plates I really didnt need but fancied the look of, and I still have 2 tubes of Green Glue, 1 full sheet of Soundblock, 2 slabs of Rockwool and a dozen 1.5m offcuts of Resilient bar left over for the dining room when/if I do that.

Just seen your post Ricardus I have similar problem and am thinking now that is a lot if effort. It would be helpful to know if it has worked abd stopped the sound as well as you hoped

It's probably less effort than it sounds, me not being a professional I was doing a lot of this for the first time and without an assistant to hold things, pass tools and make me feel guilty about stopping for tea breaks

I honestly can't tell yet as I haven't moved back into the room and my current neighbours make very little noise. My install is mainly to prevent my noise getting out.
But the theory is sound (No pun intended)

I've refurbished a few terrace houses and I have to say and old school fix seemed to work out the best...

Strip the wall back to brick. PVA and then Sand/Cement the wall to about 1". Then put a skim coat over that.

If your able to, put a thicker coat on.

Cheap, a little messy but simple.

Much denser than existing prob. lime / mortar / render

Any quick fixes for this kind of issue in a leased property? Or is it strictly for the landlord?

The two quick fixes: (1) Have a polite word with your neighbours. (2) Buy some ear plugs

These aren't intended to be flippant or facetious answers. They truly are the only quick fix solutions because everything that actually works involves changing the structure of the building. That's a big commitment when you're a house owner. But as a renter then it's pretty much impossible without the landlord's approval; and would you really want to tip £2000+ in to a property that you don't own?

Generally speaking there are three components to effective sound-proofing.

(1) Decouple. This is about stopping the noise getting to you in the first place

(2) Add mass. Heavier things are harder to move

(3) Seal up. Sound energy travels by structural vibration and by air. You have to deal with both to be fully effective

Retrospective sound-proofing tends to focus on #2 and #3


There are a range of materials that come under the heading "mass loaded barrier". These are in either sheet or roll form and are applied either as panels or like a wall paper. Unlike Anaglpyta or woodchip though, these products are a combination of a base material and rubber and are designed to add mass to a wall and provide a way of converting vibration in to another form of energy: Low-level heat. Thicknesses vary from 1.2mm up to 4mm, and the mass they add can be as little as 1kg per square metre up to 7kg/m2. Price varies with performance. Work on roughly £10-£20 per sq mtr plus the cost of adhesives and edge sealants. The flat might be a bit pongy for a while too while the product cures before you can finally redecorate.

Everflex AC95 acoustic sealant is used to seal up the air gaps. It's about £6-£7 per 900ml tube. You'll use quite a few.

Once you find these products then you'll also find the products to deal with noise from the ceiling and from the floor.


Did we help? Then use the THANKS button. It's free and it marks good advice for other readers

Have used a lot of phonestar boards,cost around £1k materials only per floor.wall or ceiling.

Some info at http://www.acaraconcepts.com/

Does anyone know if you can use ac50 in between boards like green glue?
I’ve done a resilient stud and am double boarding it with purple board. I hadn’t counted on green glueing this wall but the transmission is quite high.

The measures I’ve taken around the house so far have had a notable effect but haven’t solved my problem entirely .
However I just stripped an adjacent wall and realised the neighbour noise was louder than ever but at the wrong end of the house !
I was aware of flanking noise (or thought I was) as vibrating the walls either side of the party wall but this appears to be much more than that . I can hear full normal level conversations word for word by exposing the cavity gap in the window reveal, it’s true the joists sit in this ( non party ) wall but I feel this is more than that at the level of transmission. I’ve done a bit more exploratory work and found the air vents in these house are not tunnelled, it’s just an opening into the cavity and an opening at the other end - I think this is what’s happening. Without (or possibly in addition to!) replacing my neighbours airbricks, I can’t help but think cavity insulation would help. Has anyone ever used cavity insulation for noise?