Covering Installation Guide / Defects and malfunctions in wall and floor tilings / Defects in tile-to-tile joints / Joints with pinholes and craters
Joints with Pinholes and Craters
Visualisation
The surface of the joint contains irregularly distributed large pores and craters. They appear immediately after the grout is applied and, in some cases, arise again even when the tiler smoothes over the bottom of the joint with his finger or a pointing trowel.
Defect assignment
Grout compositions are designed to provide the grouts with good rheological performance in the fresh state, in addition to always being compatible with good workability in their application, a matter for which the professional tile fixer is always grateful. That is one of the reasons why the preparation and mixing conditions indicated by the manufacturer should always be observed. The use of a low-speed mixer, with a stirrer that provides total uniformity of the material and facilitates the removal of air bubbles trapped in the mixture; observance of the rest time and subsequent remixing, and the exact water proportioning indicated by the manufacturer, are the main factors which, under normal environmental conditions, will yield a creamy paste, without lumps, ready to be applied with the appropriate tool: a sharp-edged rubber trowel, which will allow optimum filling without oscillations in the material.
The other factor in avoiding these types of defects is observance of the times recommended by the manufacturer for the start of the grouting operation after the tile installation. Too much water and bad mixing of the components are the main causes of pits and craters.
Another case is the hardly avoidable presence of small bubbles trapped in the reactive resin grouts, which are usually very sensitive to ambient temperature and become more viscous as temperature rises. Re-pointing these with a rounded tool or a pointing trowel will help eliminate pinholes in this type of material.
Prevention
To avoid or at least reduce the appearance of pores and craters in the surface of the joint:
The surface of the joint contains irregularly distributed large pores and craters. They appear immediately after the grout is applied and, in some cases, arise again even when the tiler smoothes over the bottom of the joint with his finger or a pointing trowel.
Defect assignment
Grout compositions are designed to provide the grouts with good rheological performance in the fresh state, in addition to always being compatible with good workability in their application, a matter for which the professional tile fixer is always grateful. That is one of the reasons why the preparation and mixing conditions indicated by the manufacturer should always be observed. The use of a low-speed mixer, with a stirrer that provides total uniformity of the material and facilitates the removal of air bubbles trapped in the mixture; observance of the rest time and subsequent remixing, and the exact water proportioning indicated by the manufacturer, are the main factors which, under normal environmental conditions, will yield a creamy paste, without lumps, ready to be applied with the appropriate tool: a sharp-edged rubber trowel, which will allow optimum filling without oscillations in the material.
The other factor in avoiding these types of defects is observance of the times recommended by the manufacturer for the start of the grouting operation after the tile installation. Too much water and bad mixing of the components are the main causes of pits and craters.
Another case is the hardly avoidable presence of small bubbles trapped in the reactive resin grouts, which are usually very sensitive to ambient temperature and become more viscous as temperature rises. Re-pointing these with a rounded tool or a pointing trowel will help eliminate pinholes in this type of material.
Prevention
To avoid or at least reduce the appearance of pores and craters in the surface of the joint:
- Mix the cementitious grout with an appropriate birdcage mixer with a low-speed drill
- Observe the mixture instructions of the manufacturer
- Cool the RG grout if the ambient temperature is high and smooth over the joints with a pointing trowel immediately after applying the material
Mailing address:
Diputación Provincial
Avda. Vall d'Uixó, 25
12004 Castellón
Opening hours
From Monday to Friday: from 8.00 a.m. to 3.00 p.m.
From May 15 to Oct. 15
From Monday to Friday: from 8.00 a.m. to 2.00 p.m.
Contact
Phone (+34) 964 35 99 02
Fax (+34) 964 35 99 40
E-mail: ipcdip@dipcas.es
