I have radiant in-floor heating and want to add soundproofing to the same floor assembly, is that possible?

Yes, you can absolutely combine radiant in-floor heating with effective soundproofing in the same floor assembly — it just requires careful layering so that neither system undermines the other. The key is understanding that radiant heat needs to move upward through the finished floor, while sound isolation needs mass, decoupling, and air sealing to block noise from travelling between levels. With the right build-up, you can achieve both goals in a single assembly.
Building the Right Layer Sequence
The most effective approach starts from the subfloor up. First, install a layer of acoustic mineral wool such as Roxul Safe'n'Sound between the floor joists below — this absorbs airborne sound in the cavity without interfering with the radiant system above. On top of the subfloor, apply a mass loaded vinyl (MLV) layer at 1 lb/sqft density ($1.50–$3.00 per square foot for material), which adds critical mass to block sound transmission. Above that, your radiant tubing or electric mat sits within a thin-set or self-levelling compound, and then your finished flooring goes on top. The total build-up typically adds 1.5 to 2.5 inches of height, which you need to plan for at doorways and transitions.
One important consideration in Ottawa is vapour barrier placement. With radiant heat warming the floor assembly from within, and Ottawa winters pushing temperatures to minus thirty outside, moisture drive becomes complex. In a basement slab application, the vapour barrier must go below the insulation layer to prevent ground moisture from migrating upward. In an above-grade floor, your contractor needs to model the dew point carefully so condensation does not form within the assembly. Getting this wrong can lead to mould and degraded insulation performance — both thermal and acoustic.
For the soundproofing layer specifically, avoid rigid foam products like XPS directly under the radiant system if your primary concern is impact noise (footsteps, dropped toys). Rigid foam transmits impact vibration readily. Instead, use a resilient acoustic underlayment designed for radiant compatibility — products like Pliteq GenieMat RST or Regupol are rated for use with heated floors and provide genuine impact isolation. These typically run $3.00–$5.00 per square foot installed and can improve your IIC rating by 15 to 20 points.
Budget-wise, combining both systems in an Ottawa home typically costs $12–$22 per square foot for the soundproofing portion alone, on top of whatever you are spending on the radiant system itself. That is roughly 10 to 15 percent less than GTA pricing for the same assembly. For a typical 300-square-foot room, expect $3,600–$6,600 for the acoustic components including labour. The Ontario Building Code requires a minimum STC 50 and IIC 50 for floor-ceiling assemblies between dwelling units, so if you are in a townhouse or condo situation, your combined assembly needs to meet or exceed those ratings.
The biggest mistake homeowners make is installing the radiant system first and then trying to add soundproofing as an afterthought — by that point your options are limited and costs increase significantly. Plan both systems together from the start. For a project like this, consulting with a soundproofing professional who has experience with radiant assemblies is well worth the investment. You can explore your options further through Sound IQ or connect with experienced contractors through the Ottawa Contractor Directory to get the layering right the first time.Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:Luxe Painting and Renovations RenoMotion Inc.BFI RenovationsLeeds Property MaintenanceSpeedy Pete's IncView all contractors →