Mike Holmes, one of Canada’s most respected contractors and television personalities, is widely recognized for his slogan, “Make it right.” His expertise in general renovations is well-regarded, and his approach is clearly described in his book.
However, it is essential to note that he is not a specialized soundproofing contractor. As a result, some of the advice he promotes regarding soundproofing may reflect common myths or misconceptions. Homeowners should be cautious and seek guidance from qualified acoustical consultants for soundproofing projects to ensure effective and reliable results.
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Soundproofing myths.
However, his knowledge of soundproofing has many gaps. He is not a soundproofing contractor, nor he claims to be one. He has several articles and YouTube videos where he dispenses soundproofing advice. In his recent article in the National Post, he propagates no less than six soundproofing myths circulating on the Internet. Many so-called soundproofing contractors pick up similar tales.
The sentences in quotes are almost verbatim from the noted article.
Soundproofing myth #1:
Fact: Adding a moderate amount of sound absorption—such as acoustic panels or soft furnishings—to a typical residential room primarily affects the noise level within that room only.
In most cases, the effect on overall noise reduction or sound transmission to adjacent spaces is minimal, making it hardly worth the effort for noise control purposes, as documented in reference [1].
Myth #2:
Fact: The idea that adding typical furniture or movable panels significantly reduces noise is incorrect. Gaps between the wall and the furniture, along with the impossibility of covering the entire wall, essentially negate any meaningful noise reduction [2].
The exception is built-in furniture that covers the entire wall and is properly sealed against it. In such cases, the resulting noise reduction can be noticeable to significant, depending on the construction and materials of the furniture.
Soundproofing Myth #3:
“Carpets can reduce noise from downstairs neighbours”.
Fact: The only effective way to significantly increase the sound attenuation of a floor is by adding substantial mass, typically doubling or more the existing floor mass [2].
Lightweight solutions such as carpet and underlayment generally cannot achieve meaningful improvement in most situations. Proper floor soundproofing usually requires structural or material modifications designed to address both impact and airborne noise.
Myth #4:
“Insulation in walls helps a lot”.
Fact: A common misconception—often promoted by some contractors—is that simply adding insulation to an existing hollow wall significantly reduces sound. In reality, the improvement is modest.
For example, adding insulation to a standard wall with 3.5” wood studs and 5/8” drywall on each side increases the STC (Sound Transmission Class) rating from STC 32 to STC 36 [3]. While this represents a measurable change, it is insufficient for most practical soundproofing needs, particularly in residential or professional spaces requiring privacy or quiet.
Soundproofing myth #5:
“Sound reducing drywall is as good as 8 layers of regular drywall”.
Fact: A widely circulated myth—likely originating from a manufacturer of sound-reducing drywall—is that the noise reduction properties of a single sheet of drywall can be meaningfully evaluated.
In reality, any drywall is only effective as part of a complete assembly, such as a wall, floor, or ceiling system. Evaluating a single sheet in isolation is meaningless, as its performance depends entirely on the assembly design, mass, insulation, and sealing around it.
Consider an existing wall constructed with 3.5” steel studs spaced 24” apart and insulated cavities. Replacing a standard drywall on one side with a sound-reducing drywall may increase the STC rating from STC 38 [2] to STC 52 [4].
However, the same wall, upgraded with two layers of standard drywall on each side, achieves STC 54 [5]. This demonstrates that adding mass to both sides of the wall is generally more effective than simply replacing one sheet with sound-reducing drywall.
The origin of the so-called “8 sheets myth” is unclear; if you have information about it, please submit feedback using the form at the end of this article.
Myth #6:
“Adding blown-in cellulose insulation into walls adds a lot of echo-dampening power”.
Fact: The term “echo dampening power” is unclear and not a recognized metric in acoustical engineering.
I do not recommend blowing insulation into existing walls, despite the fact that many so-called soundproofing contractors promote this approach. As discussed previously, the effect of insulation in wall cavities is modest even when walls are filled perfectly. Since perfect fill cannot be guaranteed with blown-in insulation, the expected noise reduction is unreliable and generally insufficient for most soundproofing needs.
In conclusion, it is essential not to rely solely on soundproofing advice from celebrity contractors, regardless of their reputation. Likewise, caution is warranted when considering the advice of so-called soundproofing contractors.
A poorly implemented soundproofing project can be costly and frustrating. The contractor profits from the work regardless of the outcome, while the client may be left living with unwanted noise or facing the expense of redoing the project, effectively doubling the cost.
Many of my clients have had this unfortunate experience; an illustrative example is described elsewhere in this article. Engaging a qualified acoustical consultant from the outset can help ensure effective, reliable, and economically sensible results.
Professional guidance on soundproofing from a building acoustics engineer is not expensive and should be considered an essential component of any well-executed soundproofing project.
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References
[1] Sound absorption
[2] Master Handbook of Acoustics
[3] National Building Code of Canada
[4] QuietRock gypsum boards
[5] National Gypsum
