As we have mentioned above Dot and Dab is also known as Direct Bonding. It is a way to get plasterboard fixed to a wall.
Why use Dot and Dab Plaster Boarding?
There are four options for fixing plasterboard to a wall:
- Screwing to studs or battens
- Nailing to studs
- Gluing pre insulated plasterboard (thermal insulation board) to walls
- Fixing with plasterboard adhesive, known as Dot and Dab or Direct Bond
Each of these has their merits and will be used in different circumstances. If you are going to use dry lining or plasterboard, it is generally thought to be a good idea because it provides extra sound and heat insulation and is quicker than most other options such as wet plastering.
Dot and dab is used where there is no stud wall to screw (or nail) the plasterboard to. It is much quicker to use a direct bond to stick the plasterboard directly to the wall rather than having to build a stud frame first. It is a very quick and effective way to dryline an internal masonry of brick wall.
The other advantage is that it is a much less skilled job than plastering directly on to the masonry which will save time and money, especially if done yourself.
How to Attach Plasterboard to a Wall Using the Dot and Dab Technique
Invariably you will be fixing to a masonry wall; if there were a stud wall you would use these to screw the plaster boards to.
There are 6 simple steps:
Prepare the wall
Masonry walls will absorb a lot of moisture which will “suck” the moisture out of the adhesive that you use, meaning that it will not cure effectively.
To stop this happening we suggest that you prepare the wall by painting on a coat of PVA, mixed with water to the manufacturers recommendation. Many dry liners simply soak the wall with water before dry lining but you must remembre they can probably line a wall a lot quicker than you so PVA will give you a little more time. Allow to dry completely.
Cut the Boards
Measure up your walls and cut the boards to size. See our project on how to cut plasterboard sheets here if you are unsure of the best way to do this.
The adhesive will go off surprisingly fast so make sure that you're ready and don't have to spend precious time cutting boards to size when you should be fixing them to the wall.
Make sure you remember to cut the boards for plugs, switches and other fixtures that need it.
Mix the Adhesive
The adhesive can either be skim plaster, typically mixed a little thicker, or a specialist plasterboard adhesive.
Unless you are experienced at using skim plaster we suggest that you use plasterboard adhesive as there will be mixing instructions and you will have a little more time before it sets.
Proprietary dry wall adhesives can be called a range of names, from plasterboard adhesive to bonding compound, but make sure that it is for designed for use with plasterboard.
Mix the adhesive in a clean bucket so as not to contaminate the mix. Follow the instructions on the packet.
You are looking for a thick creamy consistency that which can stand on the hawk. If it's too runny add some more adhesive, too stiff, add a little water.
Dotting and Dabbing the Adhesive
This is where you apply the adhesive to the wall, once the PVA has dried. The amount that you use will depend to some extent on the plasterboard that you use; heavier, thicker boards will need more dabs to support the extra weight. If your wall is uneven put more adhesive in the “low” spots and less in the “high” spots so that it will be easier to get the plasterboard level/perpendicular.
Apply the dabs of adhesive every 8 inches (20 cm) to 12 inches (30 cm); be bold an apply a good dollop.
Contrary to popular belief there is no requirement to apply a full line of adhesive around the board to prevent fire spreading through the cavity.
The plasterboard itself is rated at 30 minutes fire protection. it is however recommended to apply continuous adhesive all around each board to stop any insects being able to get in behind the boards and nesting.
When the boards are pressed down on closely spaced dabs of adhesive they will join to satisfy this requirement, and you don't want to have too much adhesive to get the boards level.
The adhesive around the board will support the edges where they are more likely to get damaged. Take particular care around the bottom of the wall where the skirting boards will be fixed, so that these can be secured easily. Make sure that there is a line of adhesive just above the line of the skirting.
Add the Plasterboard
Offer your pre-cut boards up so that the adhesive grabs and holds them.
Use a long spirit level and straight feather edge tool to get the board level, square and perpendicular. Take particular care with the first piece of board as all the others will need to fit flush against this while also being vertically square.
Tap the board into position and then press home firmly so that the adhesive will give a firm fix. Don't tap with your spirit level as this could damage it.
Leave a gap between the floor and the boards for movement to occur. On a ground floor it's worth making this gap larger, a couple of inches at least, to ensure that damp cannot get from the floor to the boards, which are very hydroscopic and will absorb any moisture around if they can.
With subsequent boards you will need to make them flush with the already fixed boards, but you can use your feather edge to take the level from them to make then square.
Finishing the Wall
There are a couple of options for finishing the wall. Typically we will skim the wall with a thin plaster coat – find out how to skim plaster your walls here. The other option is to dryline the wall, which is quicker, easier and doesn't require any specialist skills, however some think that it is not such a good finish. Find out how to dry line plasterboard here.
Following this 6 simple steps will ensure that you can get your plasterboard walls finished using the dot and dab technique very quickly and relatively easily. This is well within the reach of any DIY enthusiast.
Problems and Considerations with Using Dot and Dab Plasterboard
The biggest issues with using dot and dab, or direct bonded plasterboard is that it can be very difficult to fix to. This is the case with plasterboard fixed to studs too, because plasterboard is so soft it cannot support any real weight. For more information on plasterboard fixings and how to fix to plasterboard see our project here.
Plasterboard that has been fixed using Dot and Dab present a unique problem that standard plasterboard fixings cannot overcome because there is not sufficient gap between the wall and the back of the plasterboard for the fixing to work.
What happen is that the screw or fixing is unsupported from the wall for a couple of inches, as the plasterboard provides no support. The screw will bend when any load is added to it and rip through the plasterboard.
The solution is to use a specialist dot and dab plasterboard fixing, such as the Corefix. These types of fixings offer support for the screw beyond the wall where it is fixed.
By supporting the screw that will hold the load using a steel core it is possible to fix weighty objects, such as TV brackets and shelves, to a dot and dab wall now.
The alternative is to cut out a section of the plasterboard which will be hidden behind where you are planning to fix the object – TV bracket, shelves, etc. Then you can fix a wooden batten directly to the wall, which will give you a sturdy fixing point for the object you're fixing.
Clearly it is much easier to use a specialist dot and dab fixing – you can find out more about what we thought of the Corefix fixing when we reviewed it here.
Dot and Dab plasterboard has become very popular in recent times as it is a very quick and easy way to finish a wall without needing any specialist trades. A large number of new build house will use it too as it is so much quicker and then home can be finished more quickly.