Rigips joint filler
For achieving perfect surfaces
In modern drywall construction, there is a steadily increasing demand for high-quality wall and ceiling surfaces. Perfect execution is becoming an increasingly important part of a drywall installer's "business card". While quality level Q2 was sufficient a few years ago, surfaces are now largely finished to quality level Q3 or higher. To meet this market trend, it is essential to develop an in-depth understanding of the correct joint filling techniques and professional connection methods to achieve the perfect finish.
The Rigips Joint Filling Guide is a professional manual that explains how to create high-quality surfaces using Rigips' specially tailored products.
This comprehensive compendium provides skilled tradespeople with detailed instructions on how to use our joint fillers and edge protection systems correctly, as well as highlighting potential sources of error. This practical knowledge supports the crowning achievement of every drywall project: achieving the perfect surface treatment.
At RIGIPS, we see ourselves as partners to architects, specialist retailers and, in particular, contractors. With our Rigips Joint Filling Guide and our comprehensive range of perfectly coordinated system components, we enable you to create high-quality surfaces with maximum efficiency.
Basics – What are joint fillers?
DIN EN 13963
Joint fillers used for filling joints in gypsum boards are regulated by DIN EN 13963, and are categorised primarily by their curing method and application type.
Air-drying, polymer-bound joint fillers
For polymer-bound joint fillers intended for air-drying, the material cures through evaporation of the water, resulting in the fillers bonding with the contained binder.
Gypsum-based joint fillers
Gypsum-based joint fillers set through an exothermic reaction. After absorbing water, interlocking or solidifying crystals form. Some of the mixing water is therefore incorporated into the crystals.
Types of joint filling materials
Application type
As shown in the table, a distinction is made between filling compounds, finishing compounds, and joint fillers depending on the type of application. While filling compounds are used exclusively for filling joints in combination with a suitable reinforcement tape, finishing compounds are applied to create the final finish of the joints or the overall surface. If a compound is suitable for both applications and meets the requirements of DIN EN 13963, it is classified as a filling and finishing compound. Joint fillers are intended for jointing without reinforcement tape on suitable edge profiles of gypsum boards. However, the joint fillers included in the Rigips product range may also be used for finishing applications.
What distinguishes gypsum-based joint fillers?
Among powdered joint fillers containing gypsum as a binder, there are essentially two main types:
VARIO Joint Filler Type 4B in accordance with DIN EN 13963
VARIO Joint Filler Type 4B can be applied to suitable board edges without reinforcement tape and still achieves very high joint strengths.
SUPER Joint Filler Type 3B in accordance with DIN EN 13963
By contrast, SUPER Joint Filler Type 3B does not provide adequate joint strength when applied without reinforcement tape. In many cases, this would lead to cracking of the joints. For this reason, joint fillers of this type must always be used in combination with reinforcement tape.
The two described joint filler types differ in two key aspects of their formulations:
1. The gypsum binder used in VARIO Joint Filler is so-called Alpha Gypsum, whereas the gypsum binder used in SUPER Joint Filler is Beta Gypsum.
2. The SUPER Joint Filler contains only a small amount of polymer dispersion powder as an additional binder, while the VARIO Joint Filler contains a significantly higher proportion.
Alpha and Beta Gypsum are chemically identical; in both cases, they are calcium sulfate hemihydrate. However, the two types of hemihydrate differ in their manufacturing process.
Beta Gypsum is produced from raw gypsum (calcium sulphate dihydrate) by heating it at atmospheric pressure. Alpha Gypsum, on the other hand, is produced by heating raw gypsum under increased pressure in pressure vessels (autoclaves). Due to its more complex manufacturing process, Alpha Gypsum has much better, more uniform crystals than Beta Gypsum. Consequently, Beta Gypsum (or a filler based on Beta Gypsum) requires significantly more water during mixing than Alpha Gypsum (or a filler based on Alpha Gypsum) to achieve a workable consistency.
Most of this water is not needed for the gypsum to set, but it evaporates from the hardened filler. Wherever there is excess water, pores form. Since fillers based on Beta Gypsum contain much more excess water than those based on Alpha Gypsum, hardened and dried Beta joint fillers are significantly more porous and thus less dense than fillers based on Alpha Gypsum. Porous materials have lower strengths than denser materials with the same chemical composition, which partly explains why VARIO Joint Filler has a higher joint strength than SUPER Joint Filler. The other part of the explanation is that VARIO Joint Filler contains significantly more polymer dispersion powder as an additional binder, which further increases joint strength.
What distinguishes air‑drying joint fillers?
Air-drying joint fillers differ primarily in terms of their application on:
• the proportion of binder (which determines strength) and
• the proportion of lightweight fillers (which determines the density of the material).
The density of the material significantly affects the shrinkage behaviour of the filler. Generally speaking, the lighter the filler, the less the material shrinks.
However, based on our experience, the proportion of lightweight fillers also influences burn-in behaviour at the edges. Therefore, a high proportion of lightweight fillers usually exhibits higher burn-in behaviour and is only suitable as a finishing material in thicker layers. Thus, there are small but significant differences between the individual fillers.
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