D & D Plasterboard and levelling

[lidders]

Hi

Was after some help if its ok, I'm in the middle of re-doing my bathroom and i have D & D some 12.5mm plasterboard onto the walls due to old sand a cement mix ruining the walls during removal.
Now they are pretty much straight and will be tanked around the bath and around the shower, Around the shower i have hardibacker boards going up, Now when this is done I will be getting a tiler in because i want a good job done but my concern is on some of the D & D boards they aint perfectly in line due to the state of the walls underneath. Do you think its best to get this skimmed before tiling or will a tiler use more adhesive in certain parts!! Any help would be appreciated.

Wayne

 

[andy8758]

No dont get it skimmed. Firstly the plasterboard can take more weight (32kg/sq m compared to 20kg/sq m for finishing skim) and secondly, you need to allow at least 7-10 days after skimming for the finishing skim to dry out before tiling.

If you want unlipped tiles - the wall must be flat. Frankly - the cost of plasterboard and plasterboard adhesive is so cheap that I would remove the board and reinstall it flat. It is dead easy to get a perfectly flat join - when you dob and dab adhesive, gently tap the board until level with adjacent boards - then leave to dry.

Finally - I would also add some 60mm screws holding the board in place to the brick wall behind - the plasterboard bonding is only as strong as the bond - remember to apply to dust free surfaces. I normally pre-drill for 60 or 70mm x 4mm screws at 300mm centres into 7mm rawl plugs. When you fix to dob and dab bonding, carefully screw corner screws evenly first, then remaining screws applying even pressure across the plasterboard on the bonding adhesive.

 

[Time's Ran Out]

All said by Andy

But :welcome: and good luck.

 

[lidders]

Thanx for information i was actually thinking about ripping one of the boards down as we are only talking about 5mm out but thats enough to notice i guess.
Also was going reinforce the plasterboard with frame fixings as its going to be possibly floor to ceiling in slate. The big pain in doing it is that its our only bathroom so i need to keep getting it into a working state so just makes it that bit harder but thanx for helping out its appreciated.

 

[Time's Ran Out]

As Andy stated plasterboard will take 32kg weight per metre, but as this does include adhesive/grout, check the weight of the slate and you would be correct to use mechanical fixings as well.
If your using it as well this will ensure that you set out a schedule of works and keep to it, otherwise some projects take for ever and you will lose interest in it.

 

[andy8758]

Thanx for information i was actually thinking about ripping one of the boards down as we are only talking about 5mm out but thats enough to notice i guess.
Also was going reinforce the plasterboard with frame fixings as its going to be possibly floor to ceiling in slate. The big pain in doing it is that its our only bathroom so i need to keep getting it into a working state so just makes it that bit harder but thanx for helping out its appreciated.

Wow Lidders - tackling any natural stone is not for the faint hearted. A few things you should know before you start:

Check thickness - a lot of slate tiles are cut along the natural layers which means significant variations in thickness, from as little as 6mm to as much as 20mm! However, we are seeing some machined slates that are all the same thickness. Check to see what you are buying.

Weight - most natural stone tiles are around 12mm thick - which works out about 32kg per square meter(psm). The adhesive adds a further 4 kg per square meter on average. Only tile backer boaqrds are really up to taking that weight (12mm Hardibacker takes up to 52kg psm).

Levelling tiles on a floor that are different thicknesses is fiddly and time consuming. You first need to grade the tiles into at least 3 piles (thick, thin, and medium) then try and ensure that you dont lay the thickest next to the thinnest. On a wall, is even harder as gravity has a natural tendency to pull the tiles down. With tiles of different thicknesses the additional adhesive increases risk of tile slippage. A fast setting adhesive and a lot of patience is recommended.

Natural stone wont easily and cleanly break with a manual cutter. An electric tile cutter is essential.

Slate has a silica content. Dust from cutting causes silicosis. Always wet cut the tiles - an overhead cutter gives the best cuts, but a table saw can still be used. In any event, even when wet cutting use at least a FFP2 dust mask. When laid, use a non-impregnating sealer on the tiles to reduce dust build up.

Some natural stone suppliers will automatically recommend you use a polish and not a sealer on slate (sealer wont soak into slate like it does with e.g. travertine). If you are using slate in a bathroom it will be dangerously slippery when wet if a wax is used. Insist that retailer supplies you with a non-impregnating sealer.

Generally I do not recommend laying slate as being within the capabilities of the average DIY enthusiast - but I have seen some very good floors laid by novices with a little advice.

I wish you all the best with this one - you deserve all our support for even contemplating this lol!

 

[lidders]

The slate tiles were up for change trust me its the missus that has seen some that she has fallen in love with but me falling out of love with her over them will i win as i'm doing all the work!!!!!
She works for a home mag so has these great ideas but i am going to get a tiler in as i want that bit done properly.
I have renovated the whole house in a year and a half so i wont get disheartened just the old motto if a jobs worth doing.....
I will throw loads of reasons why slate wont be used or cant , we will just go back to the drawing board with that one and i will post the finish article, I would love to learn tiling as i have done pretty much all of it but i have seen tiles done badly and there is nothing worse when you have to look at it daily knowing that that tile is out etc. Cheers again for the info and my mind is set in stone now but the tiles wont be!!!