Bricks to Plasterboard

[johnhepp]

Hello all,

I am brand new to this and just wanted some advice on fixing plasterboards to a bathroom wall.

The room has recently been stripped. Three walls are now back to joists, I am going to screw new plasterboards to this, with the dark side out, for skimming by a professional later.

The exterior wall is a non cavity wall, and is now back to the bricks. There are two windows on the wall, which are to remain in place.

As it stands, this is the plan...


1. Apply a layer of browning straight onto the bricks then wait until dry
2. Use dot and dab with Dry Wall Adhesive to fix plasterboards to the browning on wall with dark side out for skimming later.

Any advice on how much adhesive to use? Should I use insulating plasterboard?

I'm fairly sure that this method will work but any advice you could offer before I begin would be appreciated.

Thanks in advance

 

[NickB_99]

I am brand new to this and just wanted some advice on fixing plasterboards to a bathroom wall.

The room has recently been stripped. Three walls are now back to joists, I am going to screw new plasterboards to this, with the dark side out, for skimming by a professional later.

A couple of things to get you started - normally you skim the lighter side of plasterboards. Also, I am assuming you are meaning standard wallboard? In a bathroom, there is a lot of moisture and standard wallboard is not ideal. You can get Moisture Resistant boards, which are green in colour. There are extra preparations also needed with MR board before plastering.

You also say that there is no cavity on your external wall. If you just D&D direct onto an outside wall like this you can get cold spots where the adhesive is, which leads to black mould formation on them.

I'd suggest a bit of reading round first - I know there's a lot of info on bathroom plastering/boarding in the plastering & rendering forum.
Some options - you may wish to consider getting it rendered, or create a stud frame on the external walls with insulation in between studs, or use insulated boards on the frame etc etc.

 

[Richard C]

I am brand new to this and just wanted some advice on fixing plasterboards to a bathroom wall.

Use Moisture Resistant board in dry areas but waterproof tile backer board in wet areas or it won’t last. No need to plaster if your tiling, it’s not necessary & will reduce maximum tile weight. As stated, MR board must be primed if plastering in non tiled areas.

The room has recently been stripped. Three walls are now back to joists, I am going to screw new plasterboards to this, with the dark side out, for skimming by a professional later.

Fix the light side out, you don’t plaster the back – many boards say “plaster this side”

The exterior wall is a non cavity wall, and is now back to the bricks. There are two windows on the wall, which are to remain in place.

Be careful with solid brick external walls, they tend to be damp & you cannot plaster/tile onto damp walls.

1. Apply a layer of browning straight onto the bricks then wait until dry

2. Use dot and dab with Dry Wall Adhesive to fix plasterboards to the browning on wall with dark side out for skimming later.

As stated, plasterboard should be fixed light side out. If you’re tiling over & tiles are medium to large format then the PB must be mechanically fixed or the lot could end up on the floor. Browning will not be a suitable base where there is any trace of damp; D&D over solid walls can also lead to cold spots causing condensation & all sorts of nasties growing in the void behind; D&D should not be relied on for supporting tiles of any weight. You may need either a waterproof render base or Dry-coat plaster base plaster but you need to ensure there is no damp. Insulating PB would be another option but use insulated tile backer board in wet areas & tile directly over that.

I would advise you do more research starting with the Plastering Forum Archive posts & how to treat solid external walls. I would also advise you read the Tiling Forum Sticky & Forum Archive posts before doing any more work or buying any tiling materials, it could prevent you making disastrous & potentially expensive mistakes. Have you decided what type/size/weight tiles you will be laying? Are you tiling the floor? Preparing a suspended floor need special attention if you want it to last any length of time.

 

[johnhepp]

Thanks for the advice, sounds like I have some research to do...

I don't think we will get away with padding out the exterior wall, as there is very limited space. I think browning and dot and dab boards on is all we have room for. At this point I'm considering just getting a professional in to board out the whole room and skim it, depending on cost.

In answer to the questions above, we are planning on tiling the shower cubicle area and above basin only. The rest of the room will be skimmed and painted with some kind of bathroom specific paint (white). Any recommendations would be appreciated. The bath is free standing so we are not going to tile near it.

We are planning on nailing 6mm plywood to the floor and then getting someone in to tile it. Is this OK?

This is probably a stupid question, but does the plumber need to get all the pipes in for new suite before we begin this work with plasterboarding the walls and getting the plywood down on the floor?

Thanks again

 

[NickB_99]

Thanks for the advice, sounds like I have some research to do...

We are planning on nailing 6mm plywood to the floor and then getting someone in to tile it. Is this OK?

From memory in the tiling forum, I think 6mm is too thin. The plywood is normally a water resistant one (made with water resistant glue in the layers) WBP I think. Have a look for recommendation of thickness.
I also think you need to screw the ply down into the joists - not nail. More secure.

does the plumber need to get all the pipes in for new suite before we begin this work with plasterboarding the walls and getting the plywood down on the floor?

I think you'd be ok with the walls plastered first. However, you definitely need to get the pipes in before the floor goes down (or at least the ones under the floor with stubs left up).

 

[Richard C]

I don't think we will get away with padding out the exterior wall, as there is very limited space. I think browning and dot and dab boards on is all we have room for. At this point I'm considering just getting a professional in to board out the whole room and skim it, depending on cost.

As I’ve already said, Browning is probably not suitable for an external solid brick wall & you should not be plastering surfaces your going to tile or you will be restricted to tiles that weight no more than around 18 kg/sqm.

In answer to the questions above, we are planning on tiling the shower cubicle area and above basin only.

If you use plasterboard in the shower, you should tank it if you want it to last; use waterproof tile backer board. As previously stated, you should only use Moisture Resistant PB in bathrooms which needs additional prep if you want it skimmed.

We are planning on nailing 6mm plywood to the floor and then getting someone in to tile it. Is this OK?

No it’s not OK; 6mm is nowhere near thick enough & your tiles will most likely fail . BS & adhesive manufacturer’s recommended thickness for over boarding is 15mm but it’s generally recognised that 12mm is sufficient in most cases. Use WBP ply only & screws every 150mm into the joist not just into the top of the floor boards; or use a decent tile backer board. What is you current floor? if it’s chipboard (which is next to useless) you’d do better to rip it up & replace with 18-25mm WBP ply, depending on joist size/pitch/span.

This is probably a stupid question, but does the plumber need to get all the pipes in for new suite before we begin this work with plasterboarding the walls and getting the plywood down on the floor?

I don’t really think I need answer that question do I . As already stated, you need to do far more research & possibly ask a lot more questions before you do any work or buy materials or you could end up making disastrous & potentially very expensive mistakes.

 

[johnhepp]

Thanks for the advice, it is much appreciated.

So, this is the plan so far....

For the three interior walls... I am going to screw green MR plasterboard up, and have it primed then skimmed later by a proffesional. Apart from the areas that will be tiled (shower and just above basin) - I will fix waterproof tile backer board.. this looks to be the standard...

http://www.tilefixdirect.com/product/MX625-125.html

As for the exterior wall, I think I will consult a builder to see what is the best thing for it.

The floor is currently down to the floorboards. There is some very old adhesive on there that we are having some issues in removing, any advice there would be good. Maybe a product that would remove it?

Anyway, when that is off completely, I will screw 18mm WBP plywood as suggested at 150mm intervals. I can then get a tiler in to fit the tiles.

Thanks again Richard and DIYnewbee99 for your advice.

 

[NickB_99]

The floor is currently down to the floorboards. There is some very old adhesive on there that we are having some issues in removing, any advice there would be good. Maybe a product that would remove it?

Anyway, when that is off completely, I will screw 18mm WBP plywood as suggested at 150mm intervals. I can then get a tiler in to fit the tiles.

I think there may be some confusion here - I think Richard C was suggesting 18-25mm if the floorboards were off (i.e. any chipboard ripped up) and going straight on joists.
For overboarding your existing floorboards, 12mm thick would suffice.
I'd imagine floorboards +18mmWBP + adhesive + tiles = thicker than you need

If overboarding, you may cover this old adhesive & not need to take off - assuming it doesn't make the floor uneven I guess!

Thanks again Richard and DIYnewbee99 for your advice.

you're welcome

 

[Richard C]

http://www.tilefixdirect.com/product/MX625-125.html[/QUOTE]
I mostly use Aquapanel but Marmox is fine.

As for the exterior wall, I think I will consult a builder to see what is the best thing for it.

Be careful some builders won’t have a clue; you’d do much better taking the advice of a “decent” plasterer or from this & the tiling forum. A search through the archive threads will bring up similar topics & IMO either a waterproof render (which you can tile straight onto) or a directly fixed insulated backer board such as this;
http://www.marmox4u.co.uk/marmox_125mm_insulation__tile_backer_board.php

The floor is currently down to the floorboards. There is some very old adhesive on there that we are having some issues in removing, any advice there would be good. Maybe a product that would remove it? Anyway, when that is off completely, I will screw 18mm WBP plywood as suggested at 150mm intervals. I can then get a tiler in to fit the tiles.

I think you misunderstood my previous posts & newbee99 has it right; the floor must be as flat & even as possible but if the adhesive is not causing such problems, you may not need to remove it just over board with either 12mm WBP or, again, tile backer board. A decent waterproof tile adhesive can be difficult to shift as will latex adhesive & a better solution may be to completely replace the floor with WBP ply which is usually my preferred option as you know where you stand with that. This will also keep the door threshold more manageable level but ply thickness will depend on your floor joist size/pitch/span.

I would advise you read the Tiling Forum Sticky & Forum Archive posts before doing any work or buying tiling materials. It’s also important to use only quality trade materials of the correct type for your tiles & tile base; cheapo own brand & DIY stuff is mostly crap. What size/type of tile are you going to be laying?