The handling of CLT requires great care and will not only determine the design of the construction but also the economy and planning of the project. To protect the CLT from precipitation and dirt during the transportation, storage and on site assembling, the timber element is always delivered packaged in plastic film or paper, separately or in bundles. If the CLT has become wet and humid it has to be given the possibility to slowly dry out to prevent the development of cracks. Some cracking has to be accepted though due to the dehydration that the CLT is exposed to during the building’s first year.

 

  • Protect the CLT outdoors with for example tarpaulins and place the CLT blocks on clean planks which are at least 250 mm high to obtain adequate ventilation under the tarpaulin.
  • Ensure that the ground is dry and flat so that the CLT elements do not move and become twisted, nor is poorly unloaded.
  • Put clean laths between the CLT elements and place the laths vertically one above the other.
  • Avoid long storage outdoors on the building site.

 

Advice at montage

 

  • Use wide slings at crane lifting and protect the edges of the CLT element with forgins or other edge protection to prevent lifting marks.
  • Ensure that work gloves, slings and other hoists are free from dirt.
  • Avoid walking on areas that are going to be visible after assembling.
  • Take necessary actions to secure the frame against wind and other strain during the construction time.
  • Fixate the CLT elements into its right place until the wind truss is installed.
  • Let the packaging remain even after installation as protection against dirt during further construction work.

 

Maintenance

The maintenance of a building with CLT components is carried out in the same way as for a house of another frame material, preferably according to a maintenance plan with a planning horizon of 10-15 years.

 

The maintenance plan should contain part plans for roof, facade, other interior and exterior surfaces, the different installation systems, devices and equipment and also the frame. It is suitable to dedicate special attention to the density of the water bearing systems, the waterproofing of bathrooms and also the facade with its penetrations.

 

The CLT frames do not require any specific maintenance. The expected life span should exceed 100 years. In some cases it occurs that the frame is stabilized with tension nods down to the foundation. The tension of these nods may need to be checked after a year or two when the wood has dried out to its final equilibrium moisture content.

 

Martinsons are pleased to assist with consultation and support about how a suitable maintenance plan should look like in each individual case. We can also give advice about how en building should be designed to ease the maintenance work as much as possible.