Continuous control and measurement of moisture in building materials on export is often a requirement in the tender control plans, and if it is not, a control plan is always made at the contractor or consultant, or a cooperation between the parties.
According to SBi's Guide to Handling Moisture in Construction from 2010, it should include the following:
- How to measure
- Number of locations and times to be measured
- Limit values for measurements
- Preparedness services to prevent or remedy moisture damage
- Separate moisture documentation at the time of delivery, possibly also to authorities (moisture expert's declaration) if this becomes a requirement in connection with the issuance of planning permission.
How to measure
The sensors from Woodsense meet the same requirements as insert meters by measuring at a predefined distance between the screws and at a predefined depth.
Number of places to measure
The number of places to be measured is a question of how much risk the actors will take. Construction experts know about the specific critical areas, for example mentioned in many BYG-ERFA experience sheets, which should be monitored.
This is partly in closed constructions, in the climate screen and at special joints.
In another section, we have defined the risk areas where we see many of our customers set up sensors.
If there are too many places to be measured, it can be considered a time-waster at the contractor. This is especially in the case that the sensors benefit, as they only need to be installed once and then they continuously send reliable continuous measurements.
If you don't want to measure in a place anymore, the sensor can be easily unscrewed and inserted in a new location. This gives the solution enormous flexibility in that it can both be used for temporary installations and also stay seated and give the client insights for better future operation.
Times to be measured
How often to measure is also no problem with a sensor solution. If the sensors are already installed on the elements from the factory, the contractor can save the time it would otherwise take to make measurements at reception, storage, installation and at closing.
It is especially at closing that the moisture level costs the contractor money, since an extended drying process can cost precious days on the construction site. Topics like CLT have often predefined values for when they can be closed to ensure that no mold occurs.
Measurements are made continuously throughout the construction process, but especially after extreme rains. A lot of wood can withstand being temporarily humidified - the important thing is to keep an eye on it drying out properly afterwards. Sporadic insert measurements, which do not always hit exactly the same spot in the tree, can be misleading.
Here, a sensor solution benefits as it is able to show a trend from the same place over a longer period of time. In our platform, the data is seen together with weather data, so it can be clearly identified whether rain has caused problems or whether the tree has dried up as planned.
After performing at 1 and 5 years of checks, it can also cost to get a construction expert to make manual moisture measurements with insert measurements to see if the building has set itself correctly. If moisture meter is built into the construction in the necessary areas, the contractor and advisor can keep an eye on the quality of the building for up to 10 years after - from their own office.
Limit values for measurements
The limit values between which measurements must relate and the values they are preferably not to reach are different depending on:
- Where in the building it is
- At what stage of construction it is
- What type of tree it is
- When on the season it is
CLT should stay at 8-12% when it is closed, even if it arrives on site with a wood humidifier of 12-14% (depending on manufacturer). Humidity in rafters varies widely over the year, but does not need more than 20% to ensure that the wood is not broken down by fungi.
With a sensor solution like the one from Woodsense, no time should be spent discussing the specific limit values. Our platform and alarm system is based on research from leading universities and institutes within building physics and wood construction.
When the sensors are detected, enter a location and type of wood. If done correctly, it will be taken into account by the algorithm so that the right alarms are sent out.