Plasterboard Taping & Jointing
Taping and jointing is used to create a smooth continuous surface across plasterboard joints before the wall or ceiling receives its final decorative finish.
Rather than applying a full traditional plaster skim across the complete board surface, tapered plasterboard joints are filled and reinforced using jointing compound and jointing tape.
The filled joints, screw heads and local imperfections are then progressively finished and sanded until the surface is ready for decoration.
Why Use Jointing Tape?
Jointing tape reinforces the junction between adjoining plasterboards.
Plasterboards can experience small amounts of movement due to changes within the building, drying, temperature and normal structural movement.
Embedding suitable jointing tape within the joint compound helps distribute stresses across the joint and reduces the risk of the plasterboard junction becoming visible through the finished surface.
Jointing tape should therefore be treated as part of the plasterboard jointing system rather than relying on filler alone across board joints.
SEMIN CE 78 Joint Fillers
The SEMIN CE 78 range consists of professional plasterboard joint fillers available with different working times.
Roundtower currently offers:
CE 78 Joint Filler 30′ — approximately 30-minute working time.
CE 78 Joint Filler 120′ — approximately 120-minute working time.
Both products are intended for filling and finishing tapered plasterboard joints in conjunction with jointing tape.
The choice between them depends largely on the size of the area, working conditions and the installer's preferred pace.
SEMIN CE 78 Joint Filler 30′
SEMIN CE 78 Joint Filler 30′ is the fast-setting option within the Roundtower range.
Its approximately 30-minute working time makes it particularly useful where rapid progress is required or where relatively small quantities can be mixed and applied at a time.
Typical applications include:
- tapered plasterboard joints;
- embedding jointing tape;
- filling plasterboard junctions;
- covering screw heads;
- local corrections;
- and smaller drylining projects where a fast turnaround is useful.
The compound mixes to a fine white paste and is designed to provide a smooth surface that can be sanded before final decoration.
When Should I Choose CE 78 30′?
The 30-minute product is particularly useful for experienced installers who want to move quickly through the jointing process.
It can also be convenient for:
- individual rooms;
- repairs;
- smaller plasterboard installations;
- short joint runs;
- and situations where waiting for a longer-setting compound would unnecessarily slow the work.
Because the working period is relatively short, only an appropriate quantity should be mixed at any one time.
SEMIN CE 78 Joint Filler 120′
SEMIN CE 78 Joint Filler 120′ provides a significantly longer working period of approximately 120 minutes.
This gives the installer more time for mixing, taping and finishing before the compound begins to set.
It is particularly useful for:
- larger rooms;
- whole-house drylining;
- longer plasterboard runs;
- contractors working across multiple joints;
- and projects where a more relaxed working time is preferred.
The longer working period can also help reduce the amount of material lost through compound setting before it has been applied.
CE 78 30′ vs CE 78 120′
Both products perform the same fundamental role: filling and finishing plasterboard joints with jointing tape.
The main difference is working time.
Choose CE 78 30′ when:
- rapid setting is important;
- smaller areas are being jointed;
- the installer is comfortable working quickly;
- or faster progression through the job is required.
Choose CE 78 120′ when:
- larger areas are being jointed;
- longer runs need to be completed;
- additional working time is useful;
- or greater flexibility is required during application.
The correct product is therefore primarily about working time and project scale, rather than one product being inherently better than the other.
Preparing Plasterboard Joints
Before jointing begins, the plasterboard should be correctly installed and securely fixed.
The joints should be:
- clean;
- dry;
- free from loose material;
- and ready to receive the jointing compound.
Screw heads should be correctly seated and should not project beyond the face of the plasterboard.
Damaged board edges or unusually large gaps may require additional preparation before normal taping and jointing begins.
Applying Jointing Compound
The first layer of jointing compound is applied into the tapered joint before the jointing tape is embedded.
The tape should be centred over the joint and pressed firmly into the compound so that good contact is achieved beneath it.
Excess compound is then removed and the joint allowed to develop sufficient strength before additional finishing layers are applied.
Subsequent coats are normally feathered progressively wider so that the finished joint blends smoothly into the surrounding plasterboard surface.
Filling Screw Heads
Plasterboard screw heads should also be filled as part of the finishing process.
The screw should first be correctly positioned beneath the face of the board without tearing the paper surface.
Joint filler can then be applied over the fixing and finished flush with the surrounding board.
More than one application may be required to achieve a completely smooth surface.
Sanding the Finished Joint
Once the jointing compound has dried sufficiently, the surface can be lightly sanded to remove minor ridges and imperfections.
The objective is to create a smooth transition between the filled joint and the adjoining plasterboard.
Excessive sanding should be avoided because it can damage the plasterboard paper or expose the jointing tape beneath the compound.
Good application technique generally reduces the amount of sanding required.
Preparing for Decoration
Before paint or another decorative finish is applied, the completed surface should be:
- dry;
- smooth;
- free from sanding dust;
- and visually consistent.
Plasterboard and jointing compound can have different levels of surface absorption.
The chosen paint manufacturer's preparation and priming requirements should therefore be followed to achieve a consistent final appearance.
SEMIN Expert Liss
SEMIN Expert Liss is different from the CE 78 joint fillers.
Rather than being primarily a plasterboard jointing compound, Expert Liss is a ready-mixed airless filling and smoothing coating designed for larger wall and ceiling surfaces.
It can be sprayed mechanically using suitable airless equipment and then manually smoothed to create a fine, even surface.
Where Is Expert Liss Used?
Expert Liss is suitable for interior finishing over suitable surfaces including:
- plasterboard;
- plaster;
- plaster blocks;
- and other compatible prepared backgrounds.
It is particularly useful where larger areas need to be smoothed efficiently before decoration.
Airless Application
Expert Liss is designed to be applied using suitable airless spraying equipment.
Mechanical application can significantly increase productivity across larger wall and ceiling areas compared with applying the entire coating manually.
After spraying, the material is smoothed manually to achieve the required finished surface.
This makes it particularly attractive for:
- new-build housing;
- apartment projects;
- commercial interiors;
- larger refurbishment projects;
- and extensive plasterboard installations.
Coverage & Drying
Expert Liss is typically applied at approximately 0.8–1.8kg/m² per coat, depending on the background and amount of filling or smoothing required.
Typical drying time is approximately 6–12 hours, although this varies according to:
- applied thickness;
- temperature;
- relative humidity;
- substrate;
- and ventilation.
Adequate drying should be allowed before sanding or applying subsequent finishes.
Jointing vs Whole-Surface Smoothing
Joint filling and whole-surface smoothing perform different functions.
CE 78 Joint Filler is used to treat plasterboard joints, tape and local fixing points.
Expert Liss is used across larger wall and ceiling areas to create a more uniformly smooth finished surface.
Where a very high-quality plasterboard finish is required, the two processes can therefore complement one another rather than being viewed as competing products.
Expert Liss Is Not a Replacement for Jointing Tape
Airless smoothing plaster should not be used as a substitute for correctly reinforcing plasterboard joints.
Plasterboard joints should first be treated using the appropriate jointing compound and tape system.
Expert Liss can then be used where a broader smoothing coat is required across the finished plasterboard surface.
Is Expert Liss Suitable over Lime Plaster?
Roundtower does not recommend Expert Liss for application over lime plaster.
It is intended principally for conventional plaster, plasterboard and related internal backgrounds.
Where an existing wall has a lime-plaster system, a compatible lime or mineral finish should be selected instead.
Choosing the Correct Product
For straightforward product selection:
Plasterboard jointing with a fast working time
→ SEMIN CE 78 Joint Filler 30′
Plasterboard jointing with a longer working time
→ SEMIN CE 78 Joint Filler 120′
Large-area airless smoothing of suitable plasterboard or plaster surfaces
→ SEMIN Expert Liss
This makes the current Roundtower range particularly easy to select according to the job being carried out.
New Build & Renovation
Taping and jointing products can be used for both new-build and renovation work.
Typical applications include:
- plasterboard partitions;
- drylined walls;
- plasterboard ceilings;
- attic conversions;
- extensions;
- housing developments;
- commercial interiors;
- and local plasterboard repairs.
The substrate and selected finishing system should always be appropriate to the individual project.
Frequently Asked Questions
What is taping and jointing?
Taping and jointing is the process of filling and reinforcing plasterboard joints with jointing compound and tape to create a smooth surface before decoration.
Do plasterboard joints need tape?
Tapered plasterboard joints are normally reinforced using suitable jointing tape embedded within the jointing compound.
What is CE 78 Joint Filler?
SEMIN CE 78 is a plasterboard jointing compound designed for filling tapered joints in conjunction with jointing tape.
What is the difference between CE 78 30′ and 120′?
The principal difference is working time.
CE 78 30′ provides approximately 30 minutes of working time.
CE 78 120′ provides approximately 120 minutes.
Which CE 78 should I use for a large project?
CE 78 120′ is generally more convenient for larger areas because the longer working period gives additional time to complete multiple joints before the compound sets.
Which product is best for quick repairs?
CE 78 30′ is particularly useful where a shorter setting time and quicker turnaround are preferred.
Can CE 78 be used over screw heads?
Yes.
It can be used for filling and finishing correctly installed plasterboard screw heads as part of the jointing process.
What is Expert Liss?
SEMIN Expert Liss is a ready-mixed airless filling and smoothing coating for suitable internal plasterboard and plaster surfaces.
Is Expert Liss a joint filler?
It is primarily a whole-surface filling and smoothing coating, rather than a replacement for the taped plasterboard jointing system.
Can Expert Liss be sprayed?
Yes.
Expert Liss is specifically designed for application using suitable airless spraying equipment before being manually smoothed.
How long does Expert Liss take to dry?
Typical drying time is approximately 6–12 hours, depending on thickness, temperature, humidity and ventilation.
Can Expert Liss be used over lime plaster?
Roundtower does not recommend Expert Liss over lime plaster. A compatible lime or mineral finishing product should be selected instead.
Can Roundtower Help with Taping & Jointing Products?
If you are working on a plasterboard, drylining or airless finishing project, contact Roundtower Lime for help selecting the appropriate joint filler or smoothing product for the scale of the work and required finish.
