A technical comparison of three jointing plasters stocked by Pelican Systems, with application tips for plasterboard finishing.
Every flawless drywall installation starts at the joints. Even the best plasterboard system can be let down by visible seams, cracking or poor finishing if the wrong jointing plaster is used. The right product helps contractors work efficiently, cuts callbacks and leaves a smooth finish with no visible joints.
For contractors and architects, the jointing plaster you specify has a direct effect on installation time, project cost, and the finished standard of the interior. Choose well and the joints disappear under paint. Choose poorly and you fight the material, lose time and risk cracking later.
This post sets out a factual comparison of three jointing plasters stocked by Pelican Systems: JUMBO Jointing, Casofour Jointfill and OMV Metajoint. It covers the technical specifications of each, a side-by-side comparison guide, and a set of trade tips for getting a flawless result on site.
Why selecting the right plaster matters
Not every project has the same requirements. Some sites need speed. Others prioritise a premium finish. Temperature, humidity, board type and installer experience all influence how a jointing plaster performs.
The right choice affects:
- Ease of application
- Working and drying times
- Sandability and finish quality
- Long-term crack resistance
Matching the product to the project can save time on-site and improve the final result.
Product profiles
JUMBO Jointing Plaster, by Pelican Systems
JUMBO Jointing Plaster is the Pelican Systems own brand drywall joint filler, formulated for rapid setting on fast-paced sites. It carries the JUMBO ultra-white and ultra-smooth finish and works both as a plasterboard joint filler and as an interior crack filler for rough surfaces before painting. The main working figures are:
- Mixing ratio: 10 to 11 litres of clean water per 25 kilogram bag, roughly 0.42 litres per kilogram. Water should be clean, neutral pH and between 5 and 30 degrees Celsius.
- Working time: 50 minutes to 1 hour. Mix only as much as you can apply within the hour.
- First layer setting time: approximately 65 minutes.
- Coverage: approximately 350 grams per square metre.
- Packaging: 15 and 25 kilogram bags.
- Shelf life: 9 months from date of manufacture, stored dry and off the floor.
On site, fill the mitred edge with a 300-millimetre spatula and bed the JUMBO tape into the compound. After drying, apply a finishing coat over the tape and make sure the screw heads and trims are fully covered.
Casofour Jointfill, the pink-coded product
Casofour Jointfill is the pink-coded product in the Casofour range, a lightweight, quick-setting jointing and filling plaster. It is manufactured from natural gypsum and lime products with nominal additives. Casofour describes it as blended with superior natural gypsum for an extremely fine finish, and it sands easily to a smooth, level joint. It is non-combustible and suits both walls and ceilings, on plasterboard joints and as an interior filler on sand cement, brickwork, and concrete.
The main working figures are:
- Composition: Manufactured from high-quality natural gypsum with carefully balanced additives for workability and setting control.
- Water to plaster ratio: 5 to 5.5 litres of clean water per ten kilograms.
- Workability: approximately 75 to 85 minutes.
- Final setting time: approximately 100 to 120 minutes.
- pH: 9 to 11.
- Packaging: 20-kilogram bags.
- Application temperature: between 5 and 40 degrees Celsius.
- Shelf life: 6 months, kept dry and covered.
Apply the first layer with a 150 millimetre jointing knife and allow it to set. Apply the second layer with a 300 millimetre steel trowel, levelled to the board surface, then sand any imperfections with fine paper once the joint is fully dry.
OMV Metajoint
OMV Metajoint is the jointing partner to the Metacote finishing range. It is a formulated and retarded gypsum hemihydrate jointing plaster that complies with DIN EN 13279-1 and is graded Category C6, the same standard the Metacote finishing plaster meets. It is used as a smooth filler for patching, bedding, and finishing gypsum boards in ceiling and drywall applications. The main working figures from the technical data sheet are:
- Composition: Manufactured from high-quality synthetic gypsum with additives at about 5% for workability and setting control.
- Mixing ratio: 45 to 0.50 litres of water per kilogram. Add twenty kilograms to 9 to 10 litres of water and allow to soak for 5 minutes before mixing to a smooth, lump free paste.
- Working time or pot life: 60 to 80 minutes.
- Final setting time: 120 to 140 minutes by cement needle test, with a typical drying time on board of 4 to 6 hours.
- Compressive strength: 5 to 3.5 newtons per square millimetre, with flexural strength of 2.0 to 3.0 newtons per square millimetre, both to DIN EN 13279-2.
- Coverage: 35 to 40 linear metres per 20 kilogram bag.
- Finish: off-white, 85 to 95 percent on the whiteness scale, with a pH of 6.5 to 7.5.
- Packaging: 20 kilogram bags and 10-kilogram buckets.
- Shelf life: 12 months, store off the floor and always dry.
On site, apply Metajoint to clean gypsum board, cover the joint with self-adhesive mesh, lightly sprinkle the surface with water, then apply with a steel trowel. Use a second coat where needed, allowing the product to set between coats, and sand to the desired finish once fully dry.
Jointing Plasters Comparison Guide
The table below brings the key specifications together so contractors and building merchants can compare them and make an informed choice.
Always check the current product data sheet for exact mixing ratios, coverage and set times before specifying or applying.
Trade tips for flawless plasterboard finishing
- Precision mixing. Always add the powder to the water, never water to the powder, and mix to a smooth, lump-free paste. Follow the ratio on the bag, for example, 5 to 5.5 litres of water per ten kilograms for Casofour Jointfill. Let the mix stand briefly where the data sheet calls for it, then use it within the stated working time.
- Tool maintenance. Keep your tools clean. Even small amounts of hardened plaster left in a bucket can dramatically shorten the working time of the next mix and lead to unnecessary waste.
- Environmental control. Temperature and humidity have a real effect on drying. Apply each plaster within the temperature range on the bag. JUMBO calls for 5 to 30 degrees Celsius, while Casofour Jointfill allows 5 to 40 degrees Celsius.
- Proper storage. Store bags off the ground on pallets in a dry, covered area. This protects the shelf life, 9 months for JUMBO and 6 months for Casofour Jointfill, and prevents premature curing caused by moisture.
Frequently asked questions
What is jointing plaster used for?
Jointing plaster is a gypsum-based filler used in plasterboard finishing. It beds the jointing tape, fills the joints between gypsum boards, and conceals screw heads, so a drywall partition or ceiling reads as one continuous, seamless surface ready for paint or wallpaper. It also works as an interior crack filler and for filling rough plaster before painting.
How long does jointing plaster take to set?
It depends on the product. JUMBO Jointing has a working time of 50 to 60 minutes, and the setting time of the first layer is approximately 65 minutes, and an estimate drying time of 5 hours. Casofour Jointfill has a workability of about 75 to 85 minutes and a final set of about 100 to 120 minutes. OMV Metajoint has a pot life of 60 to 80 minutes, a final set of 120 to 140 minutes, and a typical drying time on board of 4 to 6 hours before the next coat.
What is the difference between jointing plaster and skimming plaster?
A jointing plaster does a focused job, bedding the tape and filling the joints between plasterboards. A skimming plaster is a finishing coat spread across the whole wall or ceiling to create a smooth, paint-ready surface. Both are gypsum-based and for interior use, but they are formulated for different tasks.
How do you mix jointing plaster?
Always add the powder to the water, never water to the powder, and mix to a smooth, lump-free paste. Follow the ratio on the bag, for example, 5 to 5.5 litres of water per ten kilograms for Casofour Jointfill or add twenty kilograms of Metajoint to 9 to 10 litres of water. Let the mix soak where the data sheet calls for it, then use it within the stated working time.
Do you need tape for plasterboard joints?
Yes. Cover the joint with self-adhesive mesh fabric or jointing tape before applying the plaster. The tape reinforces the joint and reduces the risk of cracking. Bed the tape into the first coat, then apply a finishing coat over it and feather it out flush with the board. Pelican Systems stocks JUMBO Fibre Tape in 50m and 100m rolls.
How many coats of jointing plaster do you need?
Usually, two. Apply the first layer with a smaller jointing knife to bed the tape, let it set, then level the second coat with a wider steel trowel for a smooth finish flush with the board. Allow each coat to set before the next and let the joint dry fully before sanding.
Which jointing plaster should I choose?
Choose JUMBO Jointing when speed on site is the priority, Casofour Jointfill when you want an extremely smooth, easy to sand finish, and OMV Metajoint when you need a longer working window and a DIN EN 13279-1 Category C6 compliant product. Pelican Systems stocks all three so you can match the plaster to the job.
The bottom line
The right jointing plaster comes down to matching the product to your project timeline and the skill level of the team applying it. If you need rapid setting to move quickly through a fast-paced site, JUMBO Jointing is built for it. If you want an extremely smooth, highly sandable joint, Casofour Jointfill is formulated for a fine finish. If you need compressive strength and a standard compliant thin coat product, OMV Metajoint delivers it. Pelican Systems stocks all three, so you can match the plaster to the job.
Choosing the right product from the start saves time, cuts rework, and gives a professional finish.
For project specific advice, contact the Pelican Systems technical team, or visit the online store to download technical data sheets and place an order.
Useful links
Pelican Systems JUMBO plasters