Underfloor heating (UFH) is designed to be long-lasting and low maintenance, but like any heating system, it isn’t completely immune to problems. The word “leak” is enough to worry any homeowner, especially when the pipes or cables are hidden under finished flooring. The good news? Leaks are relatively rare—especially in modern systems installed correctly. Still, it’s important to know what to look for and what to do if you suspect one.

Below is a clear breakdown of the signs, causes and response steps for both water-based and electric underfloor heating.

Can Wet Underfloor Heating Leak?

Yes, water-based (hydronic) UFH systems can leak—but it’s uncommon. The pipes used are usually continuous loops of PEX or multilayer pipe, which means there are very few joints where water could escape. Most leaks happen due to damage, poor installation, or issues during later renovation.

Common Causes of Leaks in Wet UFH

• Accidental damage from drilling, nailing or screwing into the floor.
  
• Poorly installed manifold connections or pipe joints.
  
• Cracked or weak screed allowing pipes to shift or pressurise.
  
• Manufacturing defects in rare cases.
  
• Corrosion if incompatible pipework or fittings were used.
  

Can Electric Underfloor Heating Leak?

Electric UFH doesn’t use water, so it cannot “leak” in the traditional sense. However, it can fail due to:

• Cable damage (often during installation or flooring work)
  
• Moisture ingress causing faults in bathrooms or kitchens
  
• Loose or damaged connections
  

These faults may trip the electrics, stop heating in a section, or require floor lifting to repair.

Signs Your Underfloor Heating Might Be Leaking

If you have a wet system, watch for the following:

Sudden Drop in Boiler or System Pressure

A persistent drop that won’t stabilise after topping up usually signals a leak.

Damp Patches or Warping Floors

Moisture creeping up through tiles, wooden floors or carpets is often a giveaway.

Cold Spots in the Heating Zone

A leaking loop may not heat evenly.

Mould or Musty Smell

Hidden leaks can cause condensation or damp around the floor edges.

Increased Heating Bills

If the system is losing water or pressure, it may work harder to compensate.

Electric UFH issues may show as:

• Dead zones with no heat
  
• Repeated tripping of RCD or circuit breakers
  
• Burning smell or discolouration in floor areas
  

What to Do If You Suspect a Leak

Here’s what to do right away if you think your UFH system is leaking:

1. Switch Off the System

Turn off the UFH at the manifold or relevant circuit to prevent more water loss or electrical risk.

2. Check the Pressure Gauge

For wet systems, note any sudden or persistent drop in pressure.

3. Isolate the Heating Zones

If your system has multiple loops, isolate each circuit one by one to pinpoint the affected area.

4. Look for Visible Signs

Check skirting boards, flooring edges, grout lines and downstairs ceilings (if above ground level).

5. Call a Professional

Specialists can use thermal imaging, pressure testing or acoustic leak detection to locate the problem without ripping up all the flooring.

Can the Leak Be Repaired Without Pulling Up the Whole Floor?

In many cases, yes. Today’s repair methods are far less invasive than they used to be.

Techniques professionals may use:

• Thermal imaging cameras to find hot or wet spots.
  
• Tracer gas testing to identify leaks without damage.
  
• Acoustic detection for pinpointing escaping water.
  
• Minimal lift repairs, isolating only the affected section.
  

Once the leak is found, a small section of the floor can be lifted to expose the pipe. A repair coupling or pipe replacement is then fitted and reburied with screed.

How Urgent Is a Leak?

A slow leak might take weeks to show signs, but ignoring it is risky. Potential consequences include:

• Rot or mould under timber floors
  
• Damaged insulation and screed layers
  
• Compromised structural subfloors
  
• Boiler lockouts from pressure loss
  
• Higher energy bills
  

Electrical UFH faults should also be treated as urgent—especially if moisture is involved.

Can Leaks Be Prevented?

While you can’t prevent every issue, you can drastically reduce risk with good practice.

Preventative Measures

• Use qualified installers with UFH experience.
  
• Avoid drilling or cutting into heated floors without plans or detection equipment.
  
• Keep accurate layout drawings of pipe or cable runs.
  
• Pressure test the system after installation.
  
• Protect pipes during screeding and finishing stages.
  
• Always consult installers before new flooring or renovation work.
  

When to Call a Professional Immediately

You should contact a UFH specialist if:

• You see unexplained damp or floor swelling
  
• Your system won’t hold pressure
  
• Only part of a room heats up
  
• A new project involved cutting or screwing into the floor
  
• RCDs or fuses are frequently tripping (electric systems)
  

The sooner the issue is checked, the more likely you’ll avoid floor replacement or structural damage.

Final Thoughts

Underfloor heating leaks are uncommon, but not impossible—especially if the system has been damaged or poorly installed. Acting quickly when you notice pressure loss, damp spots or heating issues can save you from major disruption and repair costs.

Whether you’re dealing with a suspected leak now or want guidance on how to protect your system long term, just let me know—I’m happy to help draft repair guides, FAQs, or advice tailored to wet or electric setups.