Is it possible to fall asleep expanded clay without waterproofing
Good afternoon!
The team began to screed the floor. The problem is that they did not lay the first layer of cellophane, but immediately poured expanded clay. Now they say that cellophane is needed from above, on expanded clay. Then they began to set up beacons, etc. What consequences await me? Thanks for the help!
Natalya
Expert Answer
Good day, Natalia.
Expanded clay is made of clay by high-temperature firing, which gives it durability, inaccessible to any other insulation. At the same time, the starting material and the porous structure make the insulation hygroscopic. Absorbing moisture from the air, it not only becomes heavier, but also loses a significant part of its heat-insulating ability. For this reason, the expanded clay layer must be surrounded by a waterproofing barrier. In a word, if we talk about following the technology, then in your case the workers grossly violated it.
On the other hand, experience shows that in some cases the insulation copes with its duties perfectly and without the bottom layer of waterproofing. In particular, this applies to floor insulation of rooms on the upper floors, if they do not suffer from an excessively humid atmosphere and sudden changes in temperature. In other words, if you live on the second floor or higher, and the neighbors living below do not complain about mold on the ceiling, then, most likely, deviation from technology will not be a problem. It is for this reason that you should definitely consider how dry your home is. At the slightest doubt, ask the workers to do everything right, otherwise there will be little use from the insulation.
As for the top layer of the “warm cake”, it all depends on how the arrangement of the draft foundation. If it is a dry or wet screed, as in your case, then a simple waterproofing is suitable. When arranging the floor on wooden logs, it is better to use not a simple film, but a diffusion membrane - it will remove excess moisture from the insulation and protect it from getting wet from the outside.
