Případové studie

Single family house without a MoistureGuard monitoring system: The worst water leaks are those that are not visible and that can be found even after several years. They may cost you lots of money.

Single family house without a MoistureGuard monitoring system: The worst water leaks are those that are not visible and that can be found even after several years. They may cost you lots of money.

The story of the owner of a new house demonstrates that even the smallest material defect can cause huge problems.


The owners of a new, single story bungalow with a size of 147 square meters near Zlín decided to build their house from wood for several reasons. They found a company they wanted to use for the construction upon seeing its wooden model house. They were also encouraged by the promised construction speed, which was a deciding factor for them. To be on the safe side, the owners also decided to furnish their house with a water leak detection system, which is able to detect leaks from the water mains. When such a leak is detected, the system automatically closes the water inlet. Nevertheless, this system did not help them.

The construction of the new wooden single family house Largo was completed in 2018. From the structural perspective, the house belongs among prefabricated wooden structures with prefabricated panels and a wooden frame structure.

House damages due to a material defect

In June 2021, a map-like spot formed by mold appeared in the hallway. Based on the extent of the mold, it was obvious that the given accident occurred already several months ago. The moldy spots in the room became clearly visible much later since it takes a while before the mold visibly penetrates to the surface.

Increased moisture signs in a structure can be hidden in the interior for several months or even years. Such signs certainly do not have to appear at all places of the house. The first signs of an increased moisture can usually be observed in the form of discolored mold (often times black), which forms in seldomly ventilated locations of interior walls, for example, hidden behind furniture. In such cases it is very difficult to locate the growing problem in a timely manner.

Upon a more detailed examination and upon opening the structure, the house owner discovered that the extent of the damages of the structure is much greater than it initially appeared. Once the structure was opened, the cause of the moisture was determined. There was a microcrack in the metal elbow in the wall behind the shower, most probably caused by a production defect or material fatigue. The tiny leak was so small that it was not caught by the system, which the owners had installed during the construction. Water from the leak had thus been constantly penetrating into the structure for several months. The leak from the elbow was so small that the needle on the water meter was not moving, thus it was not possible to detect the problem.

The crack was measured and was continuously getting bigger. In the end, water was dripping from it with a speed of one liter per 16 minutes. It was all flowing away, and the moisture was absorbed by the floor underlying layers and by the squared timber.

The owners were lucky to discover the problem after one year, i.e., relatively soon. Should they find out later, the consequences would be much more serious and everything would have to be cut out and replaced. In their case, “only” microwaves were used for drying the affected areas. A simple rule applies here – the longer the structure is exposed to a high moisture, the worse the consequences are.

The owners had to pay for all the drying, services, floor tiles, bathroom wall tiles and other materials. It cost them over 1 million crowns since their warranty claim has not been accepted yet.

Solution

A fast and the only solution of the situation was to move everything out of the house. The floors were removed and the structure at the bottom part of the entire house opened. The moisture of the structural timber was subsequently measured with the objective to locate the most affected parts of the structure.

While an intensive drying of the structure using microwaves is demanding from the preparation and structure opening perspective, it is very fast when compared with other drying methods. Once the drying process was completed, the mass moisture of the wooden structure stabilized below 18%, which can be considered a safe value.

It is MoistureGuard’s turn

At this point, when the structure is opened and accessible, it is time to install the MoistureGuard system. The owner found us on his own and he contacted us since the originally installed system did not protect his house and did not help at all. Our system will be used for monitoring moisture of the affected structure parts during the rehabilitation process, but it will also remain in the structure afterwards and it will continue monitoring moisture of the house structure.

House drying method

Standard dehumidifiers are normally used for drying. However, in this case, an intensive drying method using microwave radiation, always applied directly to the wooden structure, will also be used. Microwave drying takes place in several cycles (in this case, it was repeated 3 times, always with a week-long break in between).

List of the installed sensors:

There is a total of 16 sensors installed in the house. Three combined MHT sensors are located in the bathroom by the shower area and in the utility room by the shower and water inlet. Nine HT sensors are installed at the following locations: – restroom (toilet, sink), study (water distribution lines), kitchen (sink/dishwasher and water distribution lines), utility room (washing machine/drier and water tank), bathroom (bidet/toilet and sink), freeze proof valve, one exterior HT sensor. Moreover, three flood FHT sensors are used in the kitchen, in the utility room and by the washing machine and water tank.