Underfloor heating leaking - what to do?

Leaks in the underfloor heating sound once for a terrible disaster. In most cases, the damage is not so catastrophic, and repair can often be done with very simple means. Everything you need to know about leaking underfloor heating and repairing damage can be found in this post.

Signs of leakage

  • Loss of water (heating water must always be refilled)
  • pressure drop
  • possibly noises
  • wet spots on the ground
  • Moisture damage, musty odor, mold in the floor

damage assessment

If one or more signs indicate a possible leaking underfloor heating, you should definitely order as soon as possible a heating specialist for damage detection and repair.

It is especially important to determine where exactly the damaged area can be found. Specialized companies often work with so-called thermograms, which make it visible where heating water leaks from a leak.

Frequent leaks are compression joints, but also material fatigue or installation errors can sometimes lead to very fine cracks through which then radiates heating water.

consequential damages

The leaking heating water can lead to a massive moisture penetration of the entire floor. This may also form mold. Especially insulating materials in the floor structure provide mold with an excellent breeding ground.

While pure moisture alone (without the formation of mold) alone requires drying measures, mold must always be removed mechanically so that it can not spread further. In these cases, the damage is then correspondingly greater.


An insurance usually pays even for water damage caused by a leak in the underfloor heating. Also, the (not insignificant) costs for the thermogram determination of the damage point are taken over by the insurances in the rule.

In any case, you should already clarify with the insurance when installing an underfloor heating, which damage is taken over in which cases by the insurance up to what amount. So you stand in case of damage not in the rain, and does not sit on the costs.

damage repair

There are several ways to fix the damage. The easiest way is to work with sealants.

Sealing from the inside

Underfloor heating leaks can, under certain circumstances, be sealed from the inside in a safe and durable way.

For this purpose, a special liquid sealant is added to the heating circuit. This is a mineral-crystalline liquid sealer, which automatically seals the entire heating system by silicification (much like a radiator sealant in a car).

The prerequisite is, however, that the respective leak is not greater than about 3 mm in diameter. Larger leaks can not be sealed in this way.

There, only the prying of the floor at the appropriate place and the sealing in the classical way helps. Apart from the Aufstemmarbeiten is the artisanal but also a very fast done thing.

Tips & Tricks

However, it is important to remember that in the event of damage during the heating season, it may be necessary to shut down the entire damage repair facility, and the water will generally be drained. After the repair (a few hours), the heater will have to restart and it may take 1-2 days for the control temperatures to be reached again everywhere.

Video Board: Non-Invasive Water Leak Detection | Leak Repairs in Underfloor Heating