Most Common Floor Heating Installation Mistakes and What To Do Instead
Small mistakes during radiant floor heating installation can lead to system failures, cold spots, or even voided warranties. By knowing the most common errors and how to avoid them, you’ll save time, protect your investment, and ensure your floors heat evenly. We’ve put together a list of some of the most common installation mistakes to watch out for.
1. Skipping Resistance & Continuity Checks
Always use a multimeter to check resistance before, during, and after installation. Often, people rely solely on audible or visual signals without measuring. This can cause hidden faults or broken cables that only show up after tiling. The warranty of the system may also be voided if testing is not performed and written down. Check resistance with a multimeter before, during, and after installation. Record the values and compare them to the manufacturer’s specifications.
2. Using the Wrong Circuit Type
For radiant floor heating systems with a thermostat that already has GFCI protection, a standard circuit breaker is needed. If the thermostat already includes GFCI protection, connecting it to another GFCI can cause nuisance tripping and safety issues. Use a standard circuit breaker unless the manufacturer specifies otherwise. If you purchased your thermostat from Warm Your Floor, it already has GFCI protection, so a standard circuit breaker is required.
3. Sensor Wire Errors
Sometimes two sensor wires are installed and both are connected to the thermostat. Only one sensor wire should be connected at a time. Sometimes our customers forget to install a floor sensor wire altogether. Without a sensor in the floor, the thermostat cannot accurately measure floor temperature, which leads to overheating or insufficient heat. Install one sensor in the floor and connect only that one to the thermostat. Leave the second sensor bundled as a backup.
4. Installing Heating Under Fixtures or Tiles
During installation of fixtures like toilets or shower doors, installers sometimes accidentally place heating cables beneath those fixtures. The cable might get pinched or damaged when the fixture is set and heat cannot pass through the cable. Plan your layout carefully and mark fixture zones before laying cable. Keep heating cables only in open floor areas.
5. Power Connected Too Early
Never hook up the heating cable to power until the final floor covering is completely installed and all resistance tests are passed. Turning on power too early risks damaging the cable, compromising safety, or failing warranty requirements. Test only with a multimeter until tile, grout, and mortar have fully cured.
6. Not Ordering the Correct Amount of Membrane and Cable
You must have enough membrane to cover all finished floor area. You must also only use heating cable over the usable heated area (exclude built-in items, fixtures, walls). Placing cable under those items wastes material and may cause heat loss or code violations. Make sure you order enough membrane to cover the entire finished floor but only enough cable for the usable heated area. By contacting us and getting our input, you can be certain that your entire floor will be comfortably warm.
7. Cutting the Heating Cable
Never cut the heating cable. Each floor heating cable is designed specifically to consistently maintain heating at the chosen wattage per square foot – each cable size is unique. Shortening the heating cable would lower the resistance and increase the wattage, which can cause the system to overheat. Adding heating cable to the end of another mat or cable will also alter the resistance and the system will not heat properly.
8. Not Preparing the Subfloor Properly
Uneven, dirty, or moisture-heavy subfloors cause problems like cold spots, poor adhesion, and cable damage. Also, a lack of insulation under slabs or along the perimeter allows heat to escape downward. Clean, level, and dry the subfloor before installing. Add insulation board or underlayment if the subfloor is a cold slab.
9. Inconsistent Wire Spacing for Cable Systems
It’s very important to choose a wire spacing and maintain it consistently throughout your project. Inconsistent wire spacing leads to inconsistent heating. Consider purchasing one of our mat options to avoid this issue altogether. All mats are pre-spaced, which eliminates the chance of this spacing error. Keep in mind that manufacturers have differing requirements, so look at the instructions or ask us.
10. Incorrect Thermostat or Sensor Placement
Placing sensor wires too close to walls, windows, or entryways can cause incorrect temperature readings. Using a thermostat not designed for your heating system can also lead to poor performance or failure. Place the sensor wire midway between two heating cables, away from direct drafts. Ensure also that your thermostat comes from the same manufacturer of the rest of your floor heating system to avoid compatibility issues.
Note: If you’re installing DITRA-HEAT cables, having a full DITRA-HEAT system (membrane, cables, and thermostat) is crucial. This ensures not only compatibility but also provides a warranty in case of any complications with your system. Warm Your Floor also has full floor heating kits to ensure warranty protection and compatibility.
11. Buying From an Unauthorized Seller
Ensure you’re buying from an authorized seller to avoid compatibility issues and receive a warranty for your system in case of any complications. Warm Your Floor is an authorized distributor for all products we sell. With over 25 years of experience, our staff is well-trained to handle any issue that may arise. Along with our great customer and tech support, we offer 90-day returns.
Warm Your Floor is Here to Help
Avoiding these mistakes makes your installation smoother and your radiant floor heating system more reliable. If you need assistance planning your layout, checking compatibility, or deciding on the right components, contact Warm Your Floor. Our team can guide you through your installation and answer any questions to make sure your project is done right.