MOISTURE MEASUREMENT

Parquet installer is the occupation with the final effect highly determined by propriety and quality of previous building teams' work. Considering high percentage of damages and the value of losses caused by working mistakes and the lack of knowledge - we wish to present sources, emerge and interference mechanisms of moisture, as we describe physical phenomenons occurring in concrete ceilings and floors and their influence on wooden floor's outlook. Before he starts his main work, every aware installer is obliged to measure the moisture level of the base for installing the wooden floor. This kind of measurement should be as detailed as possible. In building-site conditions it is best to use for it carbide-chemical CM meter. Some of the installers use electrical meters, but the range of mistake is to wide and very often is the cause of damage. The electrical meter is only to be used for locating the very wet spots in the floor base. One must assume that the base must dry up, but is time the only and basic parameter in drying process? The chart below describes estimated drying time for the base in optimal conditions: 20 C and 50% relative air moisture level.

But - considering the building site conditions - are we able to optimize the moisture vaporization process?

Thousands liters of water required for building the house often stay in floors and walls. Furthermore, lack of air flow and low temperatures are not conductive to drying process.

Let's imagine the concrete base, that had dried up to 3% CM level and is not able to dry in the following weeks and months. The moisture level does not decrease, making it too high to lay a wooden floor. Why is that, when the room temperature was around 20 C? The answer: too high level of relative moisture and lack of the air flow caused too high condensation of steam in the room, along with the steam pressure in the room higher than in the base itself. Routine is fatal in this case, as the level of air moisture determines rising of the same in concrete base itself.

As the example reveals, steam does not always go up, but in the effect of pressure differences, it might to other pore materials as the floor base itself.

The penetration of floor-base moisture:

One must consider that concrete-base drying process is quite slow, furthermore, small amount of moisture might go through water isolation that is leaky (even in one spot), not proper or of low quality - made for example only of steam-insulating foil. Additionally, the pressure and temperature distinction also might determine the moisture penetration, which will go through capillary micro-spaces under the wooden floor. Until the parquet is lacquered, the bulging damage is insignificant - because the moisture is freely departed from the parquet itself to the environment. Lacquering effectively stops the vaporization process (diffusive suppression) and sudden raise of moisture in the parquet planks, along with the linear size of the surface.

After-moisture in floor heating:

Before we begin the parquet installation, the very important thing is 21-day heating of the cement base. In this kind of heating, the one-time heating causes the pressure that lifts the moisture outside and up at the same time to press the moisture down and compress it in the lower parts of the base itself. As the upper part (above the surface of heating elements) dries up properly, the lower part stays wet and may cause damage to the wooden floor. After cooling and the next - shorter (about 7 days) period of heating we may "suppose" getting rid of the moisture. The word "suppose" is to mobilize us to make the last simple test for the level of after-moisture in the base. It can appear as over-zeal doing, but that is the usual practice in the countries with the higher level of parquet craft. When the heating is on we tape the steam-insulating foil and watch - best time is after the open-windows night - if the steam liquefies.