Karndean Universal: ideal for our gluedown ranges and most subfloors, this is a fibre reinforced adhesive which allows planks and tiles to be laid almost immediately after application. The fibre reinforced format reduces lateral movement during installation and offers improved indentation and shear resistance. This adhesive has GEV-EMICODE® EC1+ accreditation and is recommended for use with underfloor heating systems. Karndean Universal is applied with A2 notched trowel and needs 10 minutes or less for airing, and allows for 20 minutes working time. A U-shaped ridge, on the other hand, spreads OUT when embedding a tile into the bed. Pushing a tile into the bed of rounded ridges causes the ridge of adhesive to spread out, from the bottom, with less possibility of trapping air. Which trowel size to use? RUBI manufactures tile trowelsin two basic types, the square-notched and the U-notched. They are measured in the same manner, the first number is the width of the notches (the distance between the teeth), the second number is the depth of the notch. Karndean PSA: suitable for normal environments protected from direct sunlight, Karndean PSA is a solvent-free high grab Pressure Sensitive Adhesive with superior bonding strength. This type of adhesive is applied with A2 notched trowel and needs 20 minutes for airing, and allows for 120 minutes working time. Our adhesives are low in Volatile Organic Compounds (VOCs) with most boasting the highest GEV-EMICODE® EC1 accreditation to comply with the strictest environmental and health requirements. You can be confident that our adhesives protect indoor air quality and contribute to a healthy environment, both during and after installation.

If you want minimum 3mm bed of adhesive beneath the tile cupped by 3mm, you must use a trowel that will leave a 6mm bed of adhesive beneath the finished placement. A 12mm square-notched trowel will accomplish the proper coverage in that instance. Visual inspection The size and spacing of the trowel teeth are the basis to measure tile trowel size. This tells you how much adhesive the trowel will leave on the substrate when you spread it out. The trowel’s tooth shape and spacing determines how much adhesive is sandwiched between the tile and substrate once the tile is fully installed. For the best results, we recommend using Karndean adhesives. Specially formulated to be used in conjunction with our products, Karndean adhesives can be used in live environments without the need for special requirements or ventilation.The square ridges, put down with a square-notched trowel, tend to collapse over on each side when you embed the tile into the bed. Pushing the tile down into the bed of square ridges causes the ridges to fold over from the top of the ridge, then spread out.

Proper adhesive coverage meansa minimum of 85% total coverage beneath a tile for a dry area placement (most floors, fireplace, etc.) and 95% minimum total coverage in a wet area (showers, bath surrounds, etc.). We offer a range of four adhesives suitable for our different product formats and project situations. Determining which trowel size is correct for your tile placement depends on both the tile itself and the substrate. More accurately, it depends on how flat the tile and substrate are. The less flat the tile is, the more adhesive you need beneath it, which means a larger trowel size.There is more to that requirement such as complete coverage beneath all four corners of the tile, but those are the basics.