Under-Tile Heating Mats for Wollongong & Illawarra Bathrooms
Of all the ways to warm a bathroom floor, an under-tile mat is the one built for a renovation. Instead of pouring a new screed, the mat is rolled straight onto your existing substrate and tiled directly over — the fast, low-build-height option that barely lifts the finished floor. That matters in the Illawarra, where so many bathroom refreshes go in over an existing concrete slab and every millimetre of extra height means another threshold to chase and another door to trim. This page sits under our full Underfloor Heating range; below we compare the slimline mats and kits we stock from Thermogroup and Radiant, all chosen because they add warmth without adding bulk to a Wollongong or South Coast bathroom.
Under-Tile Mats vs In-Screed Cable — and Why You Still Need a Thermostat
The choice between an under-tile mat and an in-screed cable really comes down to build height and timing. A mat sits at just 2.5–3.5 mm thick and is laid onto the substrate at tiling stage, so it adds almost nothing to the floor and suits a refresh over an existing slab — the fast route to a warm floor. A cable set into fresh screed sits deeper, holds heat longer and is the natural pick for a new build or a floor that’s being re-poured anyway; if that’s your situation, compare the In-Screed Heating option instead. Whichever element you choose, it is only half the system: an electric floor element must be run through a floor-sensing thermostat to control temperature and schedule, so budget for one from our Thermostats & Controllers range. For where heating fits in the wider job, see our renovation timeline guide; and because the mat lives directly under your tiles, our best tile for a shower floor guide is worth a read before you lock in the finish.
Thermogroup Thermonet 150W/m² Undertile Heating Mat
Thermonet is the mat most Illawarra tilers reach for, and it’s our lead pick for a tiled bathroom floor. The heating cable comes pre-spaced on a 500 mm-wide self-adhesive mesh (the Thermonet EZ system), so it peels down and sticks to the substrate, then gets tiled straight over — no clips, no fixing, no fuss. At just 3.5 mm thick it barely lifts the floor, and its 150 W/m² output is enough to run as the primary heat source in a bathroom rather than mere supplementary warmth. It runs on standard 240 V, carries an IP68 rating for wet-area confidence and is sold by heated area, from 1.0 m² (150 W) up to 16.0 m² (2400 W), so you buy exactly the coverage your floor needs. Thermogroup back the heating mat with a lifetime warranty, and the single-ended cold tail means only one end returns to the thermostat.
Thermogroup Thermofoil PRO 140W/m² Foil Mat
Thermofoil PRO is the mat for the rooms that aren’t getting tiled. Where Thermonet goes under tile, this element is laminated into an ultra-thin 2.5 mm foil designed to be rolled out under floating floors — laminate and engineered timber — making it the pick for a bedroom, hallway or study that shares your renovation. That 2.5 mm profile is about as low-build as electric heating gets, adding barely any height under a click-lock floor. It outputs 140 W/m² on standard 240 V, suits supplementary warmth beneath floating coverings, and carries an IPX7 rating and a lifetime warranty. Like Thermonet it’s sold by area, from 5.0 m² (700 W) up to 12.0 m² (1680 W), and its 5 m single-ended cold tail gives you room to reach the thermostat position. Worth knowing about when your Wollongong project runs beyond the bathroom.
Radiant Under-Tile Cable Mat Kit — 2m² / 400W
Radiant take the all-in-one approach, and this 2 m² kit is the neat answer for a smaller Illawarra bathroom or ensuite. It’s a complete package: the 0.5 × 4.0 m (2.0 m²) cable mat plus a digital controller, floor sensor, tape and installation guide, all in one box — so there’s no separate thermostat to source. The 3 mm cable is pre-attached to a 500 mm-wide mat that rolls out over the base surface and is covered directly with tile adhesive, keeping the build-up minimal where the floor can’t be screeded. At 400 W (200 W/m²) it runs a touch warmer per square metre than the Thermonet mesh, and it installs by cutting the matting only — never the cable — then snaking it back and forth to fill the heated zone. It runs on standard 240 V, is rated IPX7, and is backed by a 10-year warranty (2 years on the thermostat). SKU UTCMK200-400W.
Radiant Under-Tile Cable Mat Kit — 3m² / 600W
Step up to the 3 m² kit when a main family bathroom needs more floor covered. It’s the same complete package — cable mat, digital controller, floor sensor, tape and guide in one box — scaled to a 0.5 × 6.0 m (3.0 m²) mat that heats roughly 3.3–3.7 m² of floor at 600 W (200 W/m²). The low 3 mm cable profile is the whole point for a renovation: the tiler only needs a little extra adhesive to bed the mat and tiles, so the finished floor sits barely higher than before — ideal over an existing Wollongong slab. Installation follows the same rule of cutting the matting and never the cable, snaking the run to fill the space. It’s a standard 240 V supply, IPX7-rated, and carries the same 10-year warranty (2 years on the thermostat). SKU UTCMK200-600W.
Not Sure Which System? Talk to Our Unanderra Team
An under-tile mat is the quick, low-profile way to a warm bathroom floor — but it isn’t the only path. If your floor is being re-screeded as part of a bigger job, a deeper In-Screed Heating cable may hold heat better for the money, and either way you’ll need to pair the element with the right Thermostat & Controller to schedule it and keep running costs down. The right choice comes down to your floor construction, your timing and how much of the room you want warmed. Serving Wollongong, Unanderra and the wider Illawarra and South Coast — bring your bathroom dimensions and floor plan into the Unanderra showroom and we’ll match you to the mat, kit and controller that suit the job.
