Plasterboard with embedded steel mesh

[endecotp]

Some of my ceilings seem to be made from a single layer of plasterboard with a metal mesh embedded in it. I think this dates from about 1980, and it's a separating ceiling from the next flat. Is this for fire resistance?

I know that mesh is used for plaster repairs, but it really looks like it's embedded within the plasterboard. Did that exist or am I mistaken?

 

[endecotp]

I've now remwoved a plasterboard wall lining and I can see the edge of this mysterious ceiling that I thought was plasterboard with mesh embedded in it:

It seems to be plaster on steel mesh lath. Hmmm.

The plan was to take this down and reconstruct it with insulation behind (and also the walls and floor; they seem to be as I expected thankfully).

Does anyone have experience with pulling this sort of ceiling down? Youtube has some terrifying videos but then that's true of most things.

How is the mesh normally fixed to the joists? I can imagine that it may not "pop off" in the way that plasterboard does from its screws. It's also not possible to use a magnet to find the fixings.

 

[KenGMac]

endecotp, good evening.

Mesh looks a lot like "Exmet" a proprietary material that reinforces Plaster.

Suggest you Google Exmet.

Because the "mesh" is a metal, a Magnet is of no use, If you need to remove the mesh a messy claw hammer will suffice.

Is the Image a wall or a ceiling?

Ken

 

[endecotp]

It's a ceiling.

 

[endecotp]

I've levered some of it out:

More surprises; what I first though was a joist is actually just a batten, and there is a layer of plasterboard above.

Feeling round the side I think I can feel the single layer of plasterboard then more wood, which presumably is the joist this time.

So what to so? The plan was to fit acoustic (e.g. wood fibre) batts between the joists and then re-board with two layers of plasterboard. But now I see that the ceiling is more substantial than I had thought, so perhaps that would not be any better acoustically. On the other hand, I now see that I have more space than I thought below the joists (the ceiling is relatively low so I can't lose more than a few mm of room height), so I could consider hanging the new ceiling on resilient bars or something.

(The two architectural technicians who looked at this thought it was a "typical Edinburgh ceiling", meaning that there would be boards half way up the joists with a layer of "deafening material" i.e. ash on top of that. But a previous upstairs neighbour told me she had had this removed "because it was dirty". No-one I've spoken to would believe that this could be true. Anyway lots of noise does come through and I need to do something about it from my side.)

 

[KenGMac]

endecotp, good evening.

Where to start??

If the Deafening ash has indeed been totally removed? which Idjit did that? Recently I has an insurance claim that was a Complaint, where the insurance Contractor removed the Ash because "it could" be damp / wet [the leak was confined to a tiny area but the entire room area of Ash was removed from below, that was the timber Ash bearers [Deafening boards] and the timber bearers on the sides of the joists, what a Numptie?

OK the best way of Re-installing the Deafening is from above [OK obvious statement] how to get some sort of Deafening retro fitted, not only that but from below?

One modern equivalent to Ash [used in Georgian / Victorian properties, because it was plentiful given the number of Coal fires] is something like "Quietex" which as I recall comes in loose form or in bags, the latter can be [with some difficulty] be retro installed, BUT? you will require to rip down the existing ceiling, fit straps to the sides of the Joists, then slip a ply? bearer to hold the weight of a bag of Quietex next is to repeat the last process over and over again, problem is when you come to the wall ? and try to get the Quietex bag into the gap then support it in place?

After all my typing I hope you have the general drift??

As for the embedded steel mesh [Exmet] it is used to form a "Framework" to bridge a gap and allow the Plaster to bridge the gap.

Could be that the Ash has not been removed over the entire area of the floor???.

Suggest you have a google at Quietex?? on that site it gives you depths of that material to achieve the required Sound attenuation

If you have a look at Sound block Plasterboard, this material will assist, BUT??? if the Ash has indeed been removed over the floor area then more drastic action could be required.

Sounds [no pun intended] like you are facing a very common Scottish Tenement problem?

 

[endecotp]

I have 3 different neighbours above me, and I suspect that every room may be different...

One flat was refurbished about when I moved here and I believe they put "new" material of some sort under their floors, but I don't know how effective it is because the owner is never there.

It is a different flat where the very peculiar previous owner said she had removed the ash. (She also removed the fireproof plasterboard around some steels in her ceiling, for similar reasons.) That is above my bathroom where ash comes out of the downlighter holes if someone runs around upstairs, so in that room the ash may be present but the boards have collapsed, or something.

I've started in this room because it is smallest (about 2x3.5m). I think I'll just press on and see what I find. I think it will come down easily enough once I have got started, but it was tricky to pry that first bit.

 

[KenGMac]

endecotp, Hi again.

Historically, the ash Deafening was retained in place by Deafening Boards, unfortunately these boards were any and all sorts of scrap timber boards, the result was / is that the gaps between the boards will allow the Ash to drop, and it is filthy dusty stuff with small partical size that seems to get everywhere.

If you are getting Ash coming out of the Downlighters the most probable cause is collapsed Deafening Boards, this combined with the location? a bathroom, very high potential for multiple leaks over time? problem with the Ash is that it retains moisture for a long time, and cannot be dried effectively, resulting in slowly rotting Deafening boards [that were not best quality to start with?]

When I specify insurance Repairs in a water damaged tenement or property with Ash Deafening I include for the total removal and replacement with a modern Equivalent - Quietex - or similar. but I have an advantage I am specifying repair from above not attempting a retro fit from below

Removal of Ash from below is a nightmare, fine dust everywhere one thing I have seen done is to use a fine water spray, but cover absolutely everything. All this prior to replacing missing areas of Ash.

It is far from Uncommon to find in any one floor areas of missing Ash and areas of Ash still in place, tracks for pipes and Cables Etc.

Ken.