Bonding or screwing plasterboard

[Need Help21]

People,

I have an existing bathroom wall that is (believe it or not) constructed of three thicknesses of plasterboard, all bonded together without any frame at all. As a result, it is around 50mm thick and feels like a stable, solid wall.

The wall in question is doing to be adjacent to a bath. I have therefore purchased some La Farge G-tec plasterboard which is designed specifically for wet rooms.

The manufacturers technical sheet says that tiles can be applied directly to the board using waterproof tile adhesive. This leads me to the following:-

1. I would appreciate suggestions as to whether or not the new sheets of waterproof plasterboard are best bonded to the existing plasterboard using a waterproof file adhesive, or screwed and countersunk directly into the existing 50mm thick plasterboard with screws.

2. A suggestion of a suitable product from question 1 would be appreciated, idealling something from screwfix would be great.

Many thanks






Need Help21

 

[Micilin]

Hi. What is on the existing plasterboard? Your bond to the new board will be fine. but it is what you are sticking to that counts ie the bond will only be as good as the substrate - loose paint, plaster etc.

The system you describe is what we call "Lamination". A timber batten is fixed to ceiling and floor, and perhaps to the walls. 12.5 boards are screwed to these battens ( fixed vertically) then on the inside (ie sitting on the batten) plank boards (say 15mm, maybe 3/4") are stuck horizontally with plasterboard adhesive , or bonding. Then onto that, the another layer of 12.5 boards stuck vertically. Used to be done quite a bit, but not much nowadays due to poor sound insulation I suppose. Different boards , or number of layers, would obviously vary thiskness

This does not give you much to mechanically fix to, I'm afraid, but see if you can get a fixing on the perimeter. Hopefuly in a bathroom it is not a wide span. Let us know.

 

[Need Help21]

Thanks for such a detailed response, no one I knew had ever heard of three layers of board, however what you say makes perfect sense as I recently removed a wall separating a small toilet and the bathroom and the wall was constructed precisely as you described.

The plasterboard that is to be secured to is in good shape. I will remove any loose paper or isolated plaster damage. Considering what you have said I would believe that mechanical securing with countersunk screws around the perimeter would be ideal, then either screws into the board everywhere else (say 200mm squares) and bonded with a suitable adhesive. I believe a mixture of both would be best which would give a large surface area of adhesive to the plasterboard with screws around the perimeter for added strength

 

[Need Help21]

any suggestions people