How to lay indoor natural stone tiles?
When laying natural stone flooring indoors, it is essential to choose the most suitable method for your project. Depending on the type of stone, the surface, and the use, two main laying methods are available: bonded laying DTU 52.1 and bonded laying DTU 51.1. Each technique offers specific advantages. Here is a comprehensive guide to help you make the best choice.
1. Bonded Laying DTU 52.1 (using bedding mortar)
Bedding laying is the traditional method used for laying natural stone flooring, particularly with a sand and cement mix. However, this technique is becoming less common due to evolving practices among installers, who now prefer adhesive laying. Nevertheless, there are certain cases where bedding laying can still be the ideal solution.
Advantages of bedding laying:
- Renovations without underfloor heating: Bedding laying remains a good solution for renovation projects where there is no underfloor heating. It avoids the 6 to 8-week waiting period for screed drying before bonding.
- Suitable for certain stones: It is particularly recommended for stair treads or stones like quartzite or slate, where there may be significant thickness variations.
However, it is essential to note that this technique is less suitable for underfloor heating systems, as the mortar used, consisting of sand and cement, does not allow for good thermal conductivity. Therefore, it is preferable to opt for bonded laying DTU 51.1 in these cases.
Practical tips for bedding laying:
- Joints between tiles should have a minimum width of 2 mm (compared to 5 mm outdoors).
- Movement joints are necessary to prevent cracking. For adhered laying, place a joint every 60 m² or 8 linear meters. For floating laying, these joints should be installed every 40 m² or 6 linear meters.
- A slope is not necessary for this type of laying.
At Minéral, we recommend using trass cement, a special cement imported from Germany. This cement contains 30 to 40% pozzolan, which helps limit the risk of efflorescence, especially on sensitive materials.
2. Bonded Laying DTU 51.1 (using an adhesive product)
The bonded laying DTU 51.1 is the most common method for laying natural stone flooring indoors. It uses a specific adhesive product, such as cement-based adhesive, to fix the tiles directly onto the substrate.
Advantages of bonded laying:
- Suitable for underfloor heating: Unlike bedding laying, bonded laying is ideal for projects with underfloor heating, as the adhesive mortar allows for better thermal conductivity and does not block heat.
- Faster and simpler: Bonded laying is also faster and more practical, as it does not require waiting for a screed to dry. It is therefore particularly suitable for construction sites where time is an important factor.
- Better adhesion and flexibility: The adhesive product allows for better adhesion between the stone and the substrate, offering a more stable and durable finish.
Practical tips for bonded laying:
- It is essential to use an adhesive product suitable for natural stones, such as C2 cement-based adhesive. For specific stones, we recommend products such as Ardex X77, which guarantee excellent performance.
- For the joint, a width of 2 mm is also required, and movement joints must be installed every 60 m² or 8 linear meters for adhered laying, and every 40 m² or 6 linear meters for floating laying.
Conclusion
The choice between these two laying methods depends on your project and specific conditions. Bedding laying remains an interesting option for renovations without underfloor heating or for stones with significant thickness variations, while bonded laying is more commonly used, particularly for installations with underfloor heating and projects requiring a faster laying time.
At Minéral, we assist you in choosing the appropriate materials and techniques for your project, to ensure durable and aesthetic natural stone flooring.
Do not hesitate to consult our team of experts for personalized advice or to discover our quality products for your indoor projects.
