digest
Short Summary
Main recommendation: Soundproof a floor by rolling out mass loaded vinyl (MLV) over the existing subfloor, then installing new flooring on top, instead of using the traditional hat channel, clip, and double drywall assembly. The speaker says this costs about $4 per square foot as a DIY job, compared with $15 to $20 per square foot for a professional traditional installation, and that it is far more effective than standard insulation and drywall upgrades.
Key Points
- Residential building codes set only a minimum sound transmission standard (STC rating), which mainly reduces conversation clarity so that voices are unintelligible but still audible; it does not provide true privacy or address impact noise.
- New houses use thin 5/8-inch OSB subfloors and engineered joists, and hard surfaces like laminate or vinyl (which often has a solid core and carries impact noise) make floor-to-floor noise worse.
- Most noise from upstairs comes from footsteps and talking, and changing the upstairs flooring can address the problem directly.
- Traditional methods (hat channel with isolation clips, insulation, and two layers of drywall with Green Glue) are costly, with materials alone around $70 per 4x8 drywall sheet and installation pushing the total to roughly $15 to $20 per square foot.
- Insulation plus two layers of drywall is described as disappointing because it only meets minimum code and does not stop impact noise.
Details Worth Noting
- Concrete instructions:
- Remove the baseboard trim from the upstairs room.
- Take up the existing flooring, which the speaker says takes only a few minutes.
- Roll out mass loaded vinyl across the room—the speaker's sample is 1-pound, 1/8-inch thick—noting that heavier, higher-pound MLV is quieter and the 2-pound option is best if available.
- Install new floor covering (the speaker mentions vinyl tile) on top of the MLV, then reinstall the trim.
- For a 12 by 12 foot room (144 square feet), the material cost is roughly $400 plus, which the speaker says can be done in one Saturday.
- Buy a larger 25-foot roll for lower cost per square foot; 10-foot rolls or smaller sections are available if working alone, and a helper is recommended for the heavy roll (the speaker estimates about 200 pounds for a 25-foot roll, though this is an estimate, not a precise spec).
- Seal electrical boxes with putty and use soundproofing caulk under drywall at the floor if using a traditional wall or ceiling assembly.
- The speaker says MLV's cost is about $1 per square foot for the vinyl itself, with the total DIY cost around $4 per square foot including the new flooring.
- The speaker notes that the hat channel system uses clips that minimize contact to one point, and that cheap clips may lack the rubber pad needed to reduce sound.
Bottom Line
Replacing or adding mass loaded vinyl under new flooring is presented as the most practical and affordable way to stop floor-to-floor noise, especially impact noise, compared with traditional drywall-based assemblies.
