SPC vinyl plank flooring is a rigid-core, 100% waterproof product that already has an attached foam or IXPE pad on the underside. That built-in layer answers the question for most rooms — no separate underlayment is needed. But there are specific situations in GTA basements, condos, and below-grade installations where an additional underlayment layer improves comfort, sound, or moisture performance. Here is what Toronto homeowners need to know before skipping or adding an extra layer.
Do You Need Underlayment for SPC Vinyl Flooring?
Most SPC vinyl plank products sold at Top Floorings Depot come with an attached pad — IXPE foam on the 6mm budget series and EVA foam on the 8mm and 10mm series. That layer is designed to serve as the underlayment. In the majority of residential installations over plywood, OSB, or existing vinyl floors, you do not need to add a separate sheet of foam or cork. Adding an extra layer in those situations adds cost and can actually make the floor too bouncy, which stresses click-lock joints and voids manufacturer warranties on some products.
The short answer: if your SPC vinyl already has a built-in pad, you typically do not need additional underlayment for a standard above-grade Toronto home installation. The longer answer depends on your subfloor, your building, and what you are trying to achieve.
What Is the Difference Between SPC Vinyl With Built-In Pad and Without?
SPC vinyl flooring has a multi-layer construction: a backing pad (IXPE or EVA foam), a rigid SPC core, a printed decorative layer, and a wear layer on top. The pad is not decorative — it serves two purposes: it cushions footfall and it acts as a vapour barrier between the floor and the subfloor beneath.
The thickness and type of the built-in pad varies by product line. At Top Floorings Depot:
- 6mm Riche budget series — 1.5mm IXPE pad attached. Suitable for most standard installations.
- 8mm Riche standard and wide plank — 2mm EVA pad attached, including Valinge 5G Drop locking. The EVA pad gives slightly more rebound and better sound absorption than IXPE.
- 10mm Riche ultra-thick series — 2mm EVA pad attached, 20mil wear layer on most colours. Built for high-traffic areas and commercial use.
If you buy SPC vinyl without a pre-attached pad — which is less common in the GTA market — you would need to install a separate underlayment. Always check the product specifications before adding a second layer, because not all SPC products are designed for double-layer installations.
When Does SPC Vinyl Need a Separate Underlayment Layer?
There are four situations where adding a separate underlayment under SPC vinyl makes sense, even when the product already has a built-in pad:
1. Basement apartments over concrete with ongoing moisture risk. The built-in IXPE or EVA pad on SPC vinyl provides some vapour resistance, but in GTA basements with ambient moisture — especially in homes with poor perimeter drainage or sumps that flood occasionally — a 6-mil or 10-mil polyethylene vapour barrier sheeting installed under the SPC adds a meaningful second line of defence. Lay the vapour barrier first, then click the SPC over it. Do not use a second foam pad in this scenario; use only the film barrier.
2. Condo and townhouse installations where your building requires an additional STC/IIC rating. Toronto condo boards and property managers often specify minimum STC (Sound Transmission Class) and IIC (Impact Isolation Class) ratings for flooring in shared-wall buildings. SPC vinyl with its built-in EVA pad typically achieves an IIC rating of 72 and STC of 72 on its own — which meets many but not all building requirements. If your building requires an IIC above 75, a specialised acoustic underlayment (not standard foam) installed beneath the SPC can boost the rating by 6–10 points. Always ask your building manager for the required rating before choosing flooring.
3. Extremely uneven subfloors that fall just outside SPC tolerance. SPC requires a subfloor with no more than 3/16" variation over a 10-foot span. If your concrete slab or plywood subfloor is close to that limit but not quite flat enough, a self-levelling compound is the correct fix — not a thick underlayment. Thick underlayment over an uneven subfloor causes the SPC click joints to flex and eventually separate. Use the right solution for the problem.
4. Radiant heating systems. Some radiant heat subfloor systems perform better with a thin (2mm or 3mm) rubber or felt underlayment that has a low thermal resistance (tog rating) so heat passes through efficiently. The built-in EVA pad on Riche SPC vinyl is already compatible with many radiant heat installations, but if your radiant system documentation specifies a particular underlayment, follow those instructions.
What Are the Benefits of Adding Underlayment Under SPC Vinyl?
In the right situation, a separate underlayment under SPC vinyl delivers measurable improvements:
- Better sound absorption — especially in multi-level homes and condo buildings. Standard SPC with EVA pad already reduces footfall noise significantly compared to glue-down LVP, but a specialised acoustic underlayment improves on that further.
- Improved comfort underfoot — EVA and IXPE pads are firm by design (SPC is rigid-core), so the cushioning effect is modest. A 2mm rubber underlayment adds a slightly softer feel without compromising the floor's stability.
- Additional moisture protection — 6-mil polyethylene film barrier under SPC in basements or over concrete slabs gives extra protection against vapour transmission from below.
- Higher thermal resistance for radiant heat — a low-tog underlayment allows radiant heat to transfer more efficiently through the floor system.
For standard GTA main-floor installations over plywood subfloors, the built-in pad handles all three of the first benefits well enough that adding another layer is rarely worth the extra cost.
Can Underlayment Under SPC Vinyl Cause Problems?
Yes — if it is the wrong type or installed incorrectly. The most common mistakes GTA homeowners and contractors make with SPC and underlayment:
Using a second foam pad on top of SPC's built-in pad. This creates too much compressibility. The click-lock joint is engineered for a specific compression range; exceeding it allows the joint to flex, gap, and eventually fail. If you are experiencing squeaking or joint separation in an SPC floor, a double foam pad is often the cause.
Using standard foam underlayment (3mm or 6mm polyethylene) in a basement. Standard foam underlayment is not a vapour barrier. In a basement with moisture from below, it traps humidity between the foam and the concrete, which can lead to mould growth and floor failure. Use polyethylene film or a combo product that is both cushioning and vapour-blocking.
Installing underlayment over a dirty or damp concrete slab. The concrete must be clean, dry, and cured before any underlayment or flooring goes down. In a new GTA home where the basement concrete was poured recently, wait until moisture readings are within acceptable range (typically below 3 lbs/1000 sqft per 24 hours on a calcium chloride test) before installing SPC.
Does SPC Vinyl Need Underlayment for Basements and Concrete Subfloors?
SPC vinyl is one of the best flooring choices for GTA basements precisely because its rigid core does not swell or warp when it absorbs small amounts of moisture — unlike laminate or hardwood. The built-in pad on Riche SPC vinyl already provides a vapour barrier between the floor and the concrete. For most basement installations, no additional underlayment is required as long as the concrete is tested for moisture and is within acceptable range.
If your basement has a history of moisture issues, water seeping through cracks, or a below-grade drain, address those problems first — no flooring product can perform properly over a persistently wet subfloor. Once the moisture situation is resolved, Riche SPC vinyl in the 8mm or 10mm series with its built-in EVA pad is an excellent choice for basement apartments, home gyms, and rec rooms.
For basements where your building's noise control requirements are strict, the combination of SPC + a thin acoustic underlayment (not standard foam) is the right specification. Ask at the Top Floorings Depot showroom — we carry options that work with SPC in both standard and condo-compliant installations.
Our Top Picks at Top Floorings Depot
All three of these SPC vinyl products come with built-in pads — no separate underlayment required for standard installations. They cover the main performance tiers in the Riche line:
Riche Cool Ash Grey 8mm SPC Vinyl — 6mm SPC core + 2mm EVA pad, 12mil wear layer, Valinge 5G Drop lock, IIC 73 / STC 72. Cool Ash Grey is a mid-tone grey that works in both modern and traditional basement and condo setups. ~13.79 sqft/box.
Riche Stone Grey Oak 10mm 20mil SPC Vinyl — 8mm SPC core + 2mm EVA pad, 20mil wear layer, widest body in the Riche lineup. The 20mil wear layer handles heavy foot traffic, pet claws, and furniture movement without showing wear — making it one of the best choices in the Riche catalogue for family basements and rental suites. 5.9" narrow plank format suits smaller rooms well.
Riche Arctic White Oak 8mm SPC Vinyl — 6mm SPC core + 2mm EVA pad, 12mil wear layer. Arctic White Oak is a light, clean colour that brightens lower-level living spaces and condo units with limited natural light — common in Scarborough and North York basement apartments and ground-floor condos. ~13.79 sqft/box.
All Riche SPC vinyl is 100% waterproof, click-lock floating installation, and suitable for concrete subfloors. If you are unsure which thickness or pad configuration is right for your project, visit the Top Floorings Depot showroom at 3781 Victoria Park Ave, Unit 1, Toronto, or call 416-499-0117 — our team will walk you through the right spec for your subfloor and building requirements.
Visit Top Floorings Depot
Top Floorings Depot
3781 Victoria Park Avenue, Unit 1, Toronto, ON M1W 3K5
www.topfloorings.com
Call 416-499-0117 | Text 416-770-8819
Showroom Hours: Monday–Friday 9–5:30 | Saturday 9–4 | Sunday Closed
We serve homeowners and contractors across Toronto, Scarborough, North York, Markham, and Vaughan. Visit our showroom to see and feel SPC vinyl products in person, or contact us for contractor pricing and bulk orders. GTA-wide delivery available.
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