Concept of Jointing and finishing

Jointing and finishing is the process though which gypsum board systems are transformed into smooth, structurally sound walls and ceilings. This process eventually determines the look of the interiors.

Levels of Jointing and Finishing

Introduction

Traditionally, the quality of a surface has been judged subjectively, with the use of phrases such as “ready-for-painting”, “ready-for-covering” and so on. However, these are not suitable for describing the level of finish. A “finished” and “ready-for-painting” surface for one person may be a sub-standard one for another.

 

The quality of finish of gypsum board is defined by the Euro Gypsum standards (based on EN 13963). The level of finish is affected by the dimensional tolerances of boards, metal framings and level of workmanship. The flatness of the drywall and ceiling also impact the level of finish.

 

Local Flatness Standards

A ruler of 200 mm applied on the cladding of the drywall, particularly at the joints, must not have a difference bigger than 1 mm between the most salient point and the point furthest away.

General Flatness Standards

A ruler of 2000 mm length applied to the face of the drywall and moved in all directions must not have a difference bigger than 4 mm between the most salient point and the point furthest away

Jointing and finishing stages

The jointing of gypsum board goes through stages Q1 and Q2 and finishing from Q3 to Q4.

Shallow light (natural or artificial) can affect the appearance of the surface. Ideally, lighting conditions where the board systems are used should be known in advance. The surface quality should not be judged by flood-lighting, and the limits of manual workmanship should be considered.

Jointing level 1 (Q1)

The basic filling of plasterboard joints (Q1) : This is recommended for Jointing Level 1 jointing of the internal layer of Gypsum boards for a double layer partition

Jointing Level 1 includes:
Filling the joints between boards
Covering screw heads

Basic filling includes the taping of the joint

Excess jointing material should be removed. Tool marks, grooves and ridges are allowed

Jointing level 2 (Q2)

Jointing Level 2 (Q2) involves Q1 + levelling the joint to the board surface with Pro-Fill / Easi-Fill

Q2 fulfills the basic requirements for walls and ceilings


The main objective is to provide continuous transition from the joint area to the board surface. The same applies to fixings, corners, and expansion joints

Jointing Level 2 includes:
Basic filling (Q1)
Smooth transition to the board surface, including sanding jointed areas if necessary. Application marks or ridges may not be totally eliminated

This type of surface is suitable for:
Medium and coarse structured wall coverings, e.g. ingrain / textured wallpaper or standard wallpaper
Matt, filling, medium and coarse structured paint coatings/coats (e.g. emulsion paints) that are applied manually with a lambskin or structured roller
Top coats (maximum particle size > 1mm)

Jointing Level 2 finish does not eliminate physical marks/ridges completely. These effects can be reduced by specifying Jointing Level 3

Finishing Level 3 (Q3)

Finishing Level 3 (Q3) Jointing and finishing in accordance with Finishing Level 3 (Q3) includes:

Jointing and finishing to Q2
Wider finishing of the joint (400 to 450mm) and a tight coat of Pro-Fill / Easi-Fill (< 1mm) to the entire plasterboard surface, filling the pores

Physical ridges and grooves are not acceptable, except the ones observed under shallow light

The level and extent of such marks is considerably lower than Q2

This type of drywall surface is suitable for
Fine structured wall coverings
Matt and fine structured paint coatings
Top coats (maximum particle size less than 1 mm)

Finishing Level 4 (Q4)

High-end drywall surface where the entire drywall is covered with a layer of Finishing Level 4 jointing material or a skimming plaster (thickness > 1mm)

The skim coat minimises any marks or traces on the drywall surface and in the joints.

Skimmed surfaces that are perfectly even and free of shading are impossible to achieve


Quality Level 4 includes:
Jointing and finishing to Q2
Covering the surface completely with Gyproc Champion Skimming Putty (thickness > 1mm)

The undesirable effects of shallow lighting are considerably reduced. Some visible imperfections in natural lighting may be acceptable because of the limits of manual workmanship

Depending on the site, it is recommended to try out or test the Q4 surface on an area of sufficient size under final lighting conditions. This job will normally be ordered separately by the client

This type of drywall surface is suitable for:
Smooth or structured glossy wall coverings, such as metal-based or vinyl wallpapers
Paints or coats up to medium gloss

Special coatings, stucco marble or similar specialist decorative finishes

In specific cases (glossy/ varnish/ wallpapers with varnish) it may be necessary to introduce additional procedures for the pre-treatment of the final drywall surface

Performance Benefits of Q4 levels of Finish
A Q4 finish delivers far superior aesthetics. This level of finish also offers significant performance benefits in acoustics and fire safety.

Effect on Acoustical Performance
Cracks affect acoustics or isolation of a drywall by "flanking" the sound. Sound can flank over, under, or around a wall or through air gaps. Noise passes through spaces at the weakest points. This air-gap, or "flanking" path, can seriously degrade the isolation quality of a wall.

A tiny crack/gap of a width of 0.1mm can reduce the overall insulation performance of a drywall by 15%
A crack/gap of a width of up to 0.5mm can reduce the performance by approximately 35%
A crack/gap of 1mm will give a dismal performance of 50%

Effect on Fire Performance
A fire-resistant system acts as a shield against fire, heat, smoke and harmful gases. Cracks or gaps reduce the fire-resistance of a drywall. Smoke and gases can easily pass through such cracks or gaps and cause discomfort and health hazards.
A Q4 level of finish not only improves the look and feel of the interiors, it also delivers superb acoustic and fire safety performance.
 

FAQs

What are the disadvantages of using pop powder or stucco for jointing and finishing instead of genuine gyproc jointing and finishing products?

POP powder/ stucco sets very fast, between 10 minutes and 15 minutes. Often, the mix sets too quickly and becomes unsuitable for jointing. This results in wastage of material -- up to 30%. Because it sets so quickly, POP/ stucco needs to be mixed in small quantities at a time, leading to increased labour costs and time.

POP and stucco are basic gluing products and are not designed to compensate for expansions and contractions in gypsum board joints. As a result, they develop cracks. Gyproc jointing products, on the other hand, are specially formulated with additives to take care of the expansion-contraction movements in the joints, preventing them from developing cracks.

Isn’t using pop/ stucco products for jointing a lot cheaper than using gyproc jointing products?

  • Jointing and finishing is a labour-intensive process. Labour costs approximately 60% to 70% of the total cost, and materials account for only 35% to 40%. Using POP/ stucco may save on material cost a bit, but this may be illusory as wastage is very high.
  • Using POP/ stucco may involve higher labour costs too. One person using POP/ stucco can finish a maximum of 300-350 sq ft in a day, while the same person can do more than 700 sq ft a day with Gyproc jointing products. This means using Gyproc reduces labour cost by more than half.
  • As a result, the total installed cost of using Gyproc products for jointing and finishing is profitable even if the material cost of POP/stucco is considerably lower.

What is the importance of jointing tape? Which tape should be used for gypsum board jointing and finishing?

Jointing Tapes reinforces the joints after jointing. They prevent cracks to the surface of the gypsum wall or ceiling. There are two types of jointing tapes:

1. Gyproc Paper Tape
2. Gyproc Glass Fibre Tape

Use Gyproc Paper Tape for best crack resistance and for acoustical and fire rated partitions. Use Gyproc Glass Fibre tape for quick jointing of gypsum board joints.

How to finish corner joints/edge joints or internal angle joints?

For jointing and finishing of corner/edge joints, use Gyproc Angle Bead along with Gyproc jointing products to get a perfect 900 angle on external corner joint/ edge joint.

For jointing and finishing of internal angle joints, use Gyproc Paper Tape along with Gyproc jointing products.

J.W. Marriott,

New Delhi

J.W. Marriott is a 5 star luxury hotel with 550 rooms located just outside the T3 airport terminal in New Delhi. The key requirement for this project was a system which would help in constructing the project faster, with walls that delivered high performance in terms of acoustics and fire rating.

View Project View All Projects

Our Solutions

Plastering

Walls set the first impression for your home. Undulated walls give a bad impression to the guests even if the interiors are decorated well. Walls that complement the beautiful aesthetics of your home without compromising on functionality is exactly what Gyproc plastering solution offers. Gyproc is the single biggest source of your levelling requirement in the industry, with products that redefine your interiors and our 350 year old brand name.

Know More

Ceilings

Ceilings offer the largest unobstructed view of a room and are the first thing people usually notice when they enter a building. The ceiling is an important element of room design and defines its aesthetics. Since a ceiling has a large surface area, it plays an important role in the acoustic and thermal comfort of a room.

Know More

Drywalls

A drywall is a high performance lightweight interior wall system consisting of a GI steel frame, encased in gypsum plasterboards on either side, attached with self-drilling drywall screws. The joints are then taped and finished with gypsum jointing compounds.

Know More

Blog