Drylining is a fast and efficient way to smooth interior walls. But there’s more to it than meets the eye. In this guide, Dave Robinson, Head of Technical Services at British Gypsum, part of Saint-Gobain Interior Solutions, explains ways for professionals to raise their drylining game.
A quick overview
Drylining is the art of fixing plasterboard to walls. Most professionals use plasterboard because it’s quicker and easier to get a smooth finish than compared to applying wet plaster directly onto the brickwork. There are two ways to dryline: you can build stud work to attach the boards; or you can use the “dot and dab” method, where you apply adhesive to the wall in small, even quantities.
In this article, we’ll be focusing on the “dot and dab” technique, discussing best practices to help dryliners and plasterers looking to improve their skills, common mistakes to avoid, and guidance on how to get it right, the first time.
Common mistakes
Drylining sounds simple on paper, right? Ensure that the boards are flat and square with each other and you’ll get a good finish for skimming. But there are a few ways you can go wrong, which can mean having to start all over again.
As a supplier of drylining materials, we’ve heard a lot of horror stories over the years. Here are a few examples of bad practices which can be easily avoided:
- Keep it clean
This sounds obvious, but you’d be amazed how often very basic issues cause problems. Issues can include poorly stored material, contaminated water or dirty buckets, and even out-of-date products. We’re using Gyproc DriWall Adhesive as the example here but it’s broadly true of all adhesives.
- Not enough adhesive
This is a really common problem, so don’t fall into this trap! Did you ever put up a poster when you were younger, but have it keep falling down because you didn’t use enough Blu Tack? You will get a similar result if you don’t use enough dabs of adhesive to fix your plasterboard.
If your dabs are too small, and/or the gaps between dabs are too wide, then you won’t create a strong enough bond between the wall and the board. Dabs should be approximately 100 mm apart and should cover at least 20% of the back of the board.
- Double dabbing at the joints
Following on from this, a common mistake is double dabbing at the board joints which can cause bulging at the seams – each board joint should have a separate row of dabs that are 25 mm in from the joint.
- Dust and water
Always make sure that the surface of the wall is completely dry before you start dabbing. Dabbing onto damp blockwork can cause plasterboard staining as the building dries out. Equally, make sure the surface is not dusty before applying the adhesive, and if necessary, apply Gyproc GypPrime to the wall to help control suction.
- Working with concrete
Precast concrete doesn’t like dabs! If you dot and dab directly onto concrete, there is an increased risk that the adhesive will not stick – we call this delamination.
Apply Thistle Bond-It before starting to dot and dab. You can apply it with a roller or a brush or if you’re an experienced dryliner you can paint it on in bands where the rows of adhesive are going to go. If you’re not sure, simply cover the entire area to be on the safe side.
Dabbing best practice
Now we’ve sussed how to avoid common mistakes, let’s focus on best practices.
- Dab size and frequency
Dabs should be applied in a regular pattern and give a minimum area of contact between the board and wall of 20%. Dabs should also be no less than 10 mm and no greater than 25 mm in thickness when compressed. A good dab should be 50-75 mm wide and 250 mm long, while the number of rows required depends on the size of the board, but typically we recommend three.
- Air seals
You should prevent unwanted air movement behind the wall lining by using continuous ribbons rather than individual dabs to create air seals. Do this around wall perimeters, openings such as windows and doors, and wall lining penetrations such as electric socket back boxes. This ribbon method will also strengthen areas around windows and doors – and can be used as a solid fix for skirting.
- Services
It is common for the cavity between the linings and the background to be used to incorporate services such as pipework. Ensure that pipes and conduits are fixed in position before you start any lining work. Additionally, large pipes should be recessed by chasing into the blockwork.
Remember that gas pipes must be installed in accordance with BS 6891, which requires pipes to be fully encased and can be done using drywall adhesive.
- Tiling
Adding tiles to a wall increases the weight on the board, which strains the adhesive and requires more mid-height dabs to secure the board. Do not start tiling until at least seven days after you finish drylining. This is to ensure that the Gyproc DriWall Adhesive and Gyproc Plasterboard are fully bonded.
Find out more
At Saint-Gobain Interior Solutions, we’ve created Building Better, an online hub featuring a range of content such as videos, podcasts, and blogs to provide the industry with the knowledge and guidance needed to Build Better. To explore the hub for yourself visit: www.saint-gobain.co.uk/building-better-hub
