Plasterboard in Bathrooms

[padstar]

Do i need to use moisture board in all bathroom areas?

Also is it acceptable to tile directly onto fresh plasterboard? I need to insulate 1 wall (the rest will be existing plaster or tile backer board). I would like to use insulated plasterboard. The alternative would be to bond insulation to the brickwork and then fixer tile backer to the insulation.

 

[oldbutnotdead]

Use moisture board or tile backer board around the bath/shower and behind the basin if you have messy splashy inhabitants. Yes tile direct to bare pb, do use 12.5mm as a minimum (9mm is very bendy, tiles aren't).
Make sure your pb is solidly fixed to walls- tiles and adhesive add a lot of weight.
Not sure if it would be thick enough to give you your required U value but you can tile direct to Marmox insulation boards...

 

[padstar]

Thanks. It's a smallish ensuite. Is it best to do all the new walls in tile backer board rather than plasterboard other than the solid plastered walls which I will leave as is?

 

[oldbutnotdead]

For the cost difference in a small room I'd say yes use tile backer or moisture board or Marmox everywhere. Again if you're fitting over insulation make sure it's well fixed (I know Gripfill etc. are strong but I prefer a lot of screws- think it's an age thing )

 

[padstar]

Yes was planning to mechanically fix with those disk things in all new areas. I wasn't planning on overboarding the sound plaster. Is that ok

 

[oldbutnotdead]

Yes was planning to mechanically fix with those disk things in all new areas. I wasn't planning on overboarding the sound plaster. Is that ok

Good plan. Yes if the plaster is good and solid, crack on- if it's falling off or sounds a bit hollow then knock it off & tile direct to brick/block (assuming inside wall)

 

[JohnD]

there is an insulated tile backerboard, which will reduce condensation on the tiles, as well as resisting water penetration. But the one I have seen was very thin.

 

[JP_]

I am in the process of doing this. Sticking all insulation and plasterboards on with adhesive foam, then fixing in place with the washers screwed into the bricks.

And I have just plasterboard on the toilet/radiator wall, 50mm kingspan and a combination of plasterboard and tilebacker board (Wickes') on the external wall, just tilebacker on the bath wall, then combo of plasterboard and tilebacker board on the other internal wall.

I've never done a bathroom, or tiled, so wish me luck!

 

[oldbutnotdead]

there is an insulated tile backerboard, which will reduce condensation on the tiles, as well as resisting water penetration. But the one I have seen was very thin.

Sounds like Marmox, it comes in various thicknesses, think the max is 50mm. It's some sort of lightweight polystyrene core so needs significant support. And the accessories (tank tape etc) aren't cheap

 

[padstar]

I am looking at using the abacus boards to line round the shower and bath. They seem to be 12mm insulated boards. On this basis can i do away with the 20mm PIR i had planned to the external wall behind the backer board/plasterboard or should i still install it behind teh abacus boards?

 

[oldbutnotdead]

You probably aren't bothering to notify the work so Building Control won't be along to tut at you- current standard for external solid walls on a refurb equates to 80mm of PIR, i'd be surprised if 12mm of Abacus board was equivalent to 60mm of PIR.
Its a comfort thing in a bathroom or shower room rather than just being about the heating bills...

 

[padstar]

correct. I have lined the rest of the house correctly but space was crucial in the bathroom and I couldn't justify reducing the room by nearly 100mm. Is 20mm PIR behind the abacus board adding much to the party?

 

[oldbutnotdead]

20mm is far better than nothing, especially if you seal it so there are no draughtholes in the wall. In a very small room you are allowed to consider thinner than 'standard' insulation requirement due to the disproportionate loss of space.

 

[padstar]

Perfect. 20mm pir it is then. Thanks for the help