Floor: what insulation between the beams?

Above a floor that is over unheated parts of the building, 10% or even more of the heat energy used can be lost. What are the possibilities to insulate an underlying wooden beam ceiling, read in this post.

Insulation of warm or cold

Basically should always be at floor insulation "From the cold side" be insulated. In the case of a floor above the basement, this would mean the basement ceiling.

An insulation from the warm side should be carried out only in exceptional cases, if nothing else is possible. Find out more in our special article.

Insulation from the warm side results in an unfavorable building physics situation, which massively favors the formation of thermal bridges and can lead to massive moisture damage.

Insulation of wooden beamed ceilings

Wooden beamed ceilings can also be insulated later. However, a corresponding effort is needed to avoid as possible a moisture load for the timber construction as possible.

As a rule, beds are installed between the beams and the ceiling is then closed with a wooden material (shuttering boards). It is important here to pay attention to the lightest possible insulation - the formerly common slag insulation is not suitable for this purpose.

However, the execution of such insulation is basically always problematic and should at least be assessed and tested by a specialist. The risk of moisture damage to the wood and possibly also to adjacent components is always very high in such internal insulation. As consequences can then threaten:

  • massive moisture penetration of other components
  • Mold
  • Infested by wood fungi
  • possibly reduction of the load-carrying capacity of the wooden structure

It is also essential to check the moisture content of the timber construction before inserting the insulation - it must under no circumstances exceed the usual values. The adjacent masonry must not be moistened or over-moistened.

Tips & Tricks

The most problematic area for dams is the beam heads. It is important to ensure that the air circulates properly. The whole problem, however, arises anyway only in single-family homes with a year of construction before 1960 and multi-family homes until about 1940.

Video Board: Removing, Insulating and Restoring a Suspended Wooden Floor. Part 2 of 3