Project – Drying out of Concrete Floors and Effect of Cast-in Heating Pipes

Project start February 2006. Completed April 2009.

The project is completed.

Danish Technological Institute has helped the Danish Flooring Industry to investigate the issues with concrete floors subject to heating. In modern office buildings and residential buildings the use of cast-in heating pipes is being used increasingly.
When floor heating is combined with moisture sensitive flooring materials, such as vinyl, linoleum and wood there is a risk of moisture damages.

The flooring industry needed information on how to deal with these issues and a laboratory investigation was conducted at Danish Technological Institute.

Especially in the winter season, it is difficult to dry out the concrete sufficiently due to a tight construction schedule. The heating pipes generate a thermal gradient across the floor thickness and increased risk of excessive moisture being trapped under the flooring. This situation causes problems with volatile organic compounds, poor indoor climate and moisture-related damages of the flooring.

A laboratory program has been carried out to determine the effect of varying concrete temperature on the relative humidity within the concrete pore system. Furthermore, the effect of temperature gradients over the floor thickness is tested and its implication on the moisture profile is evaluated. Different concretes were tested including a self-compacting concrete.

Project Objectives

• Increased understanding of the significance of the temperature gradient for drying out of concrete.
• Recommendations for procedures relating to moisture sensitive flooring on concrete floors with  heating pipes. Including procedures for determining the moisture content in the concrete.
• Knowledge of the impact  of floor heating in order to speed up the drying process during construction.

Participants

• The Danish Flooring industry 
• The Danish Association of the Ready-mixed Concrete industry