5mm vs 10mm Acoustic Rubber Underlay: Which Thickness for Which Floor

5mm vs 10mm Acoustic Rubber Underlay: Which Thickness for Which Floor
Thickness selection for acoustic underlay isn’t just about performance, it also depends on the flooring system it needs to sit beneath.
What Changes Between 5mm and 10mm
A 5mm acoustic rubber underlay provides a good balance of noise reduction and minimal added floor height, making it suitable for most residential renovation projects using engineered wood, laminate or resilient flooring.
A 10mm acoustic underlay offers meaningfully higher impact noise reduction but requires more clearance and is generally reserved for projects where acoustic performance is the primary specification driver.
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5mm: The Practical Default
For the majority of residential and light commercial floor acoustic underlay applications, 5mm rubber strikes a workable balance, enough density to meaningfully reduce footstep noise without complicating door clearances, transition strips or threshold heights during renovation.
10mm: When Performance Is the Priority
Projects with strict building code requirements for impact noise (multi-family residential, hospitality, healthcare) often specify 10mm or thicker acoustic underlayment, particularly over concrete slabs where floor height is less constrained than in timber-frame retrofit projects.
The added thickness delivers a measurable improvement in Impact Insulation Class ratings.
Matching Thickness to Flooring Type
Rigid flooring systems (engineered wood, laminate with click-lock systems) generally tolerate thicker underlay well.
Carpet installations are more flexible on underlay thickness but should always confirm compatibility with the carpet backing and any warranty requirements from the carpet manufacturer before finalizing a floor acoustic underlay specification.
What Happens If You Choose the Wrong Thickness
Specifying too thin an underlay for a project with strict acoustic requirements is the more common error, since it usually shows up only after installation, when noise complaints continue despite the underlay being present.
Specifying too thick an underlay, on the other hand, can create practical problems: door clearances that no longer work, uneven transitions to adjacent rooms with different flooring, or excessive “give” underfoot with certain rigid flooring systems that can affect the long-term integrity of click-lock joints.
Getting the thickness right the first time, based on the actual acoustic requirement rather than a default assumption, avoids both categories of problem.
When in Doubt, Ask for the Data
If a project’s acoustic requirement isn’t clearly defined upfront, the safest approach is to request tested performance data for both 5mm and 10mm options from the supplier.
Compare the actual figures against the building’s requirement or the client’s expectation, rather than guessing based on thickness alone.
This small extra step at the specification stage avoids costly rework later.
Worth a look too: Acoustic Underlay for Carpets & Floors hub, Acoustic Rubber Cork Rolls product page and How Thick Should a Rubber Sound Deadening Sheet Be?.


