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Dot and dab is a common way of securing plasterboard to walls. The process uses a drywall adhesive, that sets solid and sticks the board to the sub surface.
In most cases, the adhesion to the surface is very strong. Anyone who has ever needed to remove plasterboard adhesive will tell you, this stuff sets really hard. However, it does have two points of failure.
- The board can pop off the dabs
- And the dabs can pop off the wall.
The former is less common, unless you did something silly, like trying to dot dab foil backed plasterboards. However, the latter can happen quite easily, especially if the surface was not prepped before the boards were installed.
Getting a good fixing with new dot and dab
If the wall is particularly smooth or dusty, this will mean the adhesive doesn’t get a good grip of the surface. This means, prep before you apply the adhesive is essential. For a dusty wall, this could be as simple as wetting the area where your dabs will be placed.
Applying water will get rid of the dust and also deal with any suction in the wall. This will stop the wall pulling all the moisture out of your dabs, which can also cause the boards to pop off.
Dot and dab on smooth surfaces
If you are dealing with a particularly smooth surface. For example dot and dab onto a painted wall, the prep will need to be different. In this scenario, the wall will have very poor suction and the dabs could very likely come loose.
To help the adhesive get a grip you can use a bonding agent. This will give a better mechanical key to the surface.
A few examples of popular bonding agents include:
- WBA (Wickes bonding agent)
- Febond Blue grit
These bonding products all contain a fine aggregate grit. This provides a mechanical key and will allow your drywall adhesive to get a good grip on the surface.
Also they are bright colours, WBA is pink, blue grit is obviously blue, and Thistlebond-it is green. This allows you to only use the grit where your dabs will be placed, hence you will save a little money by not needing to prep the entire wall.
What to do if your boards come loose
If you have loose dot and dab plasterboards, it is likely that they were installed poorly in some way. Generally, the entire board won’t fall off. Instead, you will have individual dabs that come loose. This will cause a wobble, or rattle in the board.
Basically, you will be able to push the board with your hand and it will move in areas where it’s no longer attached.
At this point, removing the entire board would be a big job, so you may wonder if there is any way to fix the loose plasterboard back to the wall. The good news is there are a couple of methods you can try.
Fixing loose dot and dab plasterboard – Option 1
The first option is to try screwing the boards back with a standard plug and screw. To do this you will need:
- SDS or hammer drill, plus drill bit.
- Some 75mm screws – This will account for the 12.5mm plasterboard + dot and dab adhesive (roughly 25mm) and still give a good fixing in the wall behind.
- Some plugs – You can use red or brown plugs. This will depend on the size of your drill bit and screws.
You should fix through the dabs, so your screws don’t pull through the plasterboard . To find the dabs, push the board back and tap the wall. When you are tapping over a dab the wall will sound solid, anywhere else will have a hollow sound.
Once you have identified the location of your dab, proceed to drill straight through it. Once the hole is drilled, you can insert your plug and hammer it flush with the surface.
Next, take your screw and hammer it into the plug, pushing it into the wall. Do this until around 20-30mm of the screw remains sticking out of the wall.
Finally, ensure the board is pushed back and tighten your screw into the plug. Aim for the screw head to pull just slightly below the surface of the plasterboard (1-2mm).
If you get a good fixing the plug will expand in the drilled hole, and this will grab the board and fix it back securely to the wall.
Fixing loose dot and dab plasterboard – Option 1
Another option if you don’t have a drill, or perhaps you are struggling to get a good fixing, is to use a foam adhesive.
This is a low expansion foam adhesive. It is similar to expanding foam. However, it does not expand to the same extent. As a result it will not push your board further off the wall.
Instead, it will expand into the void behind your board and set solid. This type of foam also has far better adhesive qualities, compared with a standard expanding foam. Therefore the grip is very strong.
Generally it takes around 15 minutes to set hard.
To apply the foam adhesive, simply drill holes in the plasterboard. These should be big enough to insert the foam application nozzle inside.
Once your holes are cut, you can spray the foam in and wait for it to go off. If possible, you can also prop the board back as the foam adhesive sets. This will ensure the board is fixed securely back to the surface.
When applied correctly, dot and dab should create a strong adhesive bond for your plasterboards. However, if they do come loose, you have some options to get them fixed back securely.
Either of the above methods can work. You could even use them in combination, to get a really strong and solid fixing.