Joint filling with ready to use compound, surface quality level Q1

Previous | Next 1 out of 1
2020-07-22 07:00:00










In this video we demonstrate how to fill and reinforce plasterboard joints after wallboards installation. According to Eurogypsum’s* classification this is the prime level of surface finishing – also called Q1**.


Here are the steps we followed:


One of the most important steps in prepping a ready-to-use compound is to pre-mix it with a mechanical stirrer at a low speed after opening the package. If necessary, the compound can be diluted with up to 200 ml of water per 20 kg of product, water is added gradually to achieve the desired consistency for application.


After pre-mixing the compound, proceed with filling the joints.

Place enough of the compound to completely fill the joint and press well with a trowel to ensure a tight filling of the gap between the boards.

The strip mixture on both sides of the joint should be approx. 6 mm, i.e. slightly wider than the tape used.


After the initial filling of the joint along its entire length, place the joint tape and press it to sink into the compound.

To separate and remove the excess compound under the tape, smooth it with light pressure along the entire length of the joint. 1-2 mm thick layer of the mixture should remain under the joint strip, which is completely sufficient for strong elastic reinforcement of the joint.


Apply a second thin layer of the compound on the leveled joint with a width of approx. 15-20 mm, thus finally leveling the joint with the rest of the wall surface.


Important notes:


  • Use paper joint tape when reinforcing the factory tapered edges of the plasterboards. The paper tape has microperforations and at the same time high elasticity, which prevents the joint from cracking when the substrate moves.
  • Use fiberglass tape to reinforce non-factory joints (square ones), which has a minimum thickness and allows precise alignment of the wall. It is mandatory to pre-cut the non-factory joints at an angle of 45 ° to 2/3 of the thickness of the board (so-called chamfer) to facilitate the entry of the mixture into the joint. 





*Eurogypsum – European federation of the gypsum product manufacturing industry. Developed and established, the 4 levels of quality finish classification for plasterboard cladding aims to provide clear definitions thus helping to reduce subjective judging of the end result.

**Level Q1 is a basic requirement for joints filling between the gypsum wallboards (including the visible parts of the screws) and is considered sufficient for surfaces with following decorative thin-layered coatings. The surface achieved with level Q1 is suitable for ceramic wall tiles and coarse structured wall coating with thickness of at least 2mm, etc.