QuietRock vs Double Drywall: Which Is Better for Soundproofing?

Are you like me and trying to choose between QuietRock vs double drywall to soundproof walls and ceiling in your media, games or bedroom? Determining which will give the best results for the price can be difficult.

Which Is Better for Sound Reduction? QuietRock or Double Drywall? QuietRock can improve the soundproofing by 15 to 20 points on the STC scale, while it will take up to four sheets of drywall to have the same effect. If you’re doing both sides of a partition wall, that’s 2 sheets of QuietRock for 8 of the gypsum.

 In this article, I’ll take a look at QuietRock and compare its installation and soundproofing with regular drywall. I’ll also look at the similarities and differences of soundproof with QuietRock vs. double drywall.

Quietrock vs Double Drywall

What is QuietRock Sheetrock?

QuietRock is a sound damping product that has a viscoelastic material sandwiched between two gypsum layers. The gypsum has the mass to block soundwaves, and the viscoelastic material damps the wave vibrations. Combined the sheet will reduce the transmission of sound in or out of a room by between 15 and 20 STC points when compared to standard drywall sheets.

The sheets are available in thicknesses of 1/2″, 5/8”, and 1-3/8”, with dimensions of 4’x8’, 9’, or 10-feet. The lengths are tapered for taping and mudding, plus it can be scored and snapped the same as regular sheets. The 5/8” 4×8 sheet weighs 83.2-pounds (2.6 lbs/ft²). Prices of building materials like drywall and QuietRock fluctuate, so check with suppliers for current prices.

Types of QuietRock Panels

EZ-SNAP ($60-$65)

5/8” thick 4×8’, 9, or 10’’ sheets that score and snap easily, and can be used the same as standard drywall, but with better soundproofing performance. The panels attach directly to the studs or joists, so takes up less space than other standard drywall attenuation techniques. A 4×8 sheet weighs 83.2-pounds and has an STC value between 48 and 60 depending on wall construction.

EZ-SNAP Mold Resistant

Similar to EZ-SNAP but with mold-resistant paper and soundproofing core material. A 4×8 sheet weighs 83.2-pounds and is ideal for damp locations or bathrooms. Depending on wall assembly, it has an STC rating between 48 and 60.

QuietRock 510 ($55-$60)

A less expensive option, the 1/2″ thick 4×8’, 9, 10’ and 12’ gypsum panels also have a sound damping core. They can be installed directly over existing drywall to improve STC rates to between 47 and 52.

QuietRock 530 ($105-$110)

A denser 5/8” panel available in 4×8’, 9’, 10’ and 12’ sizes, and the 4×8 weighs 105.6-pounds (3.3 lbs/ft²). It is shear rated for almost 500-pounds and has an STC 52 and 74 depending on the construction methods used.

QuietRock 530 RF

The 530 RF is the same as the 530, but with added shielding against radio frequency penetration to provide high security for information-sensitive locations. Installation requires different preparation to ensure the radio frequencies are blocked, and a skill saw to cut or trim. It is impact resistant and can be used on walls, ceilings, and floors for full protection and STC rankings between 52 and 74.

QuietRock 545

An 11 layered high-performance drywall panel that is recommended for home or commercial studios, sound rooms, or theaters. The 1-3/8” thick 4×8’ sheets are a hefty 200-pounds (6.25 lbs/ft²). They have tapered edges and are STC rated between 60 and 80 depending on wall construction. 545 works well even on low-frequency noise too.

Benefits

The benefits of using QuietRock over other drywall products are many. Layer to layer it provides better sound attenuation, which reduces the need for additional layers, resilient or hat channels, and viscoelastic material. Time and budget constraints are additional savings as a wall can be finished in one pass, instead of multiple passes for different layers of material.

A single layer of QuietRock also means you don’t give up floor-space to additional layers too. The panels finish the same as regular drywall, have an equivalent fire and smoke rating, but reduce noise transmission better.

STC ratings

The sound transmission class (STC) is third party verified, so it isn’t skewed like some big companies do. The STC ratings are based on wall construction, not individual panels. That means to achieve comparable values; wall construction needs to be similar. The Product Datasheet for each QuietRock product provides images of the wall assemblies and the STC. It is also recommended that soundproof caulking be used to seal the 1/4″ gap left where the wall meets the ceiling, floor, and other walls or openings.

Fire Rating

QuietRock is fire rated similar to regular drywall compositions; one-hour rating for 5/8” sheets, the 1/2″ thick 510 panels have not been tested for a fire rating. I also couldn’t find a rating for the 1-3/8” thick QuietRock 545. However, I presume it would be equal or better than the 5/8” rating. When gypsum is heated to high combustible temperatures, it will produce steam as trapped moisture evaporates.

QuietRock on Ceilings

Quiet rock can be used on ceilings to block airborne sound. Like most other drywall material, it doesn’t handle impact noise isolation. QuietRock can be attached directly over existing drywall that is attached to the joists, not to resilient channels. It also should be screwed through the existing gypsum layer and into the joists. QuietRock does not recommend the 510 product for use on ceilings due to the possibility it may sag.

Where to Buy QuietRock

The QuietRock website has a dealer locator for a location near you. The dealers may have some products in stock but not the whole product line. You will most likely need to order in depending on product, dimensions, and the number required.

QuietRock Installation

The installation of QuietRock is similar to that of regular drywall in standard applications. It should be fastened directly to the studs or to existing drywall with appropriate screws. Leave a 1/4″ between the panels and the ceiling, floor, and adjacent wall to be filled with acoustic calking.

QuietRock has a viscoelastic material inside it which damps vibration. For partition walls with 3.5-inches of insulation and wood studs every 24-inches, an STC rate of 51 can be achieved using EZ-SNAP, and an STC of 52 with QuietRock 530. Using the same insulation but with 3-5/8” steel studs at 24” centers instead, and the STC climbs to 55 and 56 respectively.

QuietRock 545 on a single stud wall has an STC rating of 56. Decoupling the wall with a double-thick stud wall and 545 takes the value to 75. Doubling up the 545 on that type of wall construction produces a quiet value of 80. However, you’re also losing 2-3/4” off the perimeter of the room.

Pros 

  • One 5/8” layer provides sound stopping results
  • Saves on labor and material costs
  • Heavier, so more sound stopping mass
  • Better STC values than regular drywall on similar wall construction.

Cons

  • Expensive
  • Difficult to use for ceilings
  • Not good for decoupling and blocking mechanical or impact noise

Types of Drywall

Drywall is sheets of gypsum wrapped in paper and commonly has tapered edges on the long sides for tape and mudding. It is known by different names and brands, such as wallboard, gypsum, gypsum board, plasterboard, and Sheetrock – which is a brand name. Different thicknesses are available for specific uses and products. The thicker materials are denser and offer more mass, which helps decrease sound transfer.

Regular or White Board drywall panels are available in 1/4” to 1” thicknesses, and 4×8’, 9’, 10’ and 12’ dimensions. Longer sheets can be special ordered. The paper on the room side is whitish, and the back, or wall side, is brownish.

Green Board is a moisture-resistant gypsum sheet. The green covering is more impervious to moisture. It isn’t waterproof but is frequently used as a backer for tiles in bathrooms, kitchens, and laundry rooms.

Blue Board is more water and mold resistant than Green Board, and is often used for plaster finishes. It has special absorption properties for use with plaster finishes; the paper isn’t made for taping, mud, or paint.

Paperless Gypsum is covered with fiberglass instead of paper and resists moisture, mold, and mildew much better. The fiberglass covering isn’t smooth, so a slick coat of joint compound is required for a smooth paint finish. The boards are also more durable than the paper coated gypsum.

Purple covered gypsum panels are similar to regular sheeting but have better moisture and mold resistance. It is ideal for basements or bathrooms where water contact is likely.

Type X is made with non-combustible material and is referred to as fire-resistant. To be fire-rated a 1/2″ thickness must achieve 3/4-hours of fire resistance, and a 5/8” thickness an hour. Required by building codes for specific locations, it commonly is used in apartments, schools, meeting rooms, and garages.

Soundproof drywall sheets have a layer of sound stopping material sandwiched between two layers of gypsum. It is denser than comparable thicknesses and blocks more sound movement. Frequently used in media rooms, or rooms requiring less noise intrusion or disruption.

STC ratings

For comparison with the QuietRock, the wall assemblies are the same. A wood stud wall with regular 5/8” drywall and 3-1/2” of insulation has an STC of 46, with steel studs that will improve that to 49. Doubling the drywall on steel studs brings the STC to 58, plus it doubles the fire rating to 2 hours. Doubling the drywall on wooden studs with insulation has an acoustic performance of 52 and two hours of fire rating.

Drywall with Green Glue Assemblies

Using Green Glue to damp sound requires two layers of drywall. The first layer of gypsum is attached to the studs. A coating of Green Glue is applied to the second sheet of drywall before it is attached to the first. Offset the seams of the second layer from those of the first, and to screw to the drywall, not the studs. The “glue” is compressed between the two layers and forms a spongy layer that absorbs sound vibrations.

Double Drywall benefits

The benefit of a double thickness of drywall with Green Glue sandwiched between is less noise penetration. The drywall adds mass, which prevents sound wave penetration, especially lower frequency, and the Glue absorbs sound vibration-damping sound vibration movement. 

QuietRock vs Double Drywall Comparison

When soundproofing a room or space, remember that the aim is to decrease the transmission of sound into or out of a room. It won’t be soundproof; it will hopefully be quieter. Whether renovating or building, the cost is always a factor, as is time – which is also money. Adding QuietRock over an existing layer of drywall will add to the mass and reduce sound transmission. It will improve the STC value by about 5 points. Drywall addresses the mass requirement, and works best for airborne sound, not impact or flanking noise.

The cost of 5/8” QuietRock EZ-SNAP is $60 to &65 for a 4×8 sheet, and 530 is $105 to $110.

The cost of 5/8” regular (non-light) drywall in my area is $12.57, so 2 sheets will cost $25.14.

A 5-gallon pail of Green Glue is about $260 and will do 365 square feet, or just over eleven 4×8 sheets, so about $23.60 a double panel.

The math works as follows: $25.14+$23.60=$48.74 for a 4×8 section of wall using double drywall vs. $60 to $110 for a layer of QuietRock. The sound transmission class ratings are compared in the table.

For a 10ft by 10ft room, the costs for doubled 5/8” regular drywall and Green Glue would be $487.40. The same room in one layer of either EZ-SNAP or QuietRock 530 is between $600.00 and $1,100.00.

 

AssemblySTC
2×4 Wood Stud Partition Wall (24” spacing) With 3-1/2” Fiberglass Installed
1/2-inch layer drywall on each side (1.6 psf)42
1/2-inch QuietRock 510 panel installed vertically on each side (2.1 psf)52
1/2-inch double layer (1” thickness) drywall on each side (3.2 psf)46
5/8-inch layer drywall on each side (2.3 psf)48
5/8-inch layer drywall on each side with resilient channel51
5/8-inch EZ-SNAP QuietRock panel installed on each side (2.6 psf)51
5/8-inch QuietRock 530 panel installed vertically on each side (4.1 psf)52
5/8-inch double layer (1-1/4” thickness) drywall on each side (4.6 psf)54
5/8-inch double layer (1-1/4” thickness) drywall on each side with Green Glue59

How to Improve Acoustic Performance

Making a room quieter means addressing the four elements of soundproofing – absorption, damping, decoupling, and adding mass. Drywall with Green Glue and QuietRock add mass and damping and address airborne sound. They don’t address mechanical (impact) or flanking noise. Check out How to Soundproof a Ceiling, and How to Soundproof Walls for further information.

Outlets, switch boxes, light fixtures, and vents are possible ways for sound to by-pass your drywall soundproofing efforts. Frequency vibrations can bounce from room to room unless they are damped too. Putty pads are a viscoelastic material that can be used to wrap electrical boxes and vents to quiet noise transfer.

Acoustic caulking is another way to damp vibration movement. There should be a gap between the drywall and the floor, ceiling, and adjacent walls. Filling the gaps with the caulking helps prevent sound movement.

Resilient clips and channels are an effective way to decrease vibrational sound waves by decoupling the wall layers. Use of resilient clips and channels can improve the STC by between 12 and 15 points.

Conclusion

Reducing the sound disruption in your home or business is a matter of controlling the four elements of sound – adding mass, damping, absorption, and decoupling. Adding fiberglass or rock wool between the studs adds absorption, and double-drywall with Green Glue or QuietRock add mass and damping.

QuietRock will take up 5/8” of floor space while double-drywall uses 1-1/4”, so if space is a factor and cost isn’t, then I’d recommend the QuietRock. However, the STC improvement between a single layer of regular 5/8” gypsum and the EZ-Snap is only 3 points, which in the world of noise, isn’t much. If you are serious about stopping the sound, doubling the drywall and adding a viscoelastic material like Green Glue, bump it 8 to 11 STC marks. Now that is sound stopping!

Hope you found this article of value. If you know someone who might benefit from it, pass it on. Your comments and suggestions are always appreciated.

Leave a Comment