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Soundproofing with Sound Deadening Board

One of the most common soundproof walls that can be built, using materials right out of the local home building store is to add sound deadening board to the faces of the studs. This is a good way of soundproofing a wall. Sound deadening board costs about $0.25 per sq ft. If it is added to both sides of a wall, which is the proper way to do it, the added material cost is $0.50 per sq ft of wall. This construction method satisfies all requirements of soundproofing. It reduces the airborne clatter inside the wall, it adds a gap of material between the gypboard and the stud which breaks the conduction of sound path. Sound deadening board reduces the strength of wall twang, the plate vibration and it can also contribute structural damping to the wall shudder effect. It generally satisfies all the requirements for making a soundproof wall.

So, what is wrong with using sound deadening board in construction of walls? Glue. The only way sound deadening board can actually "work" when the wall moves from vibration is if the soundboard is glued to the studs on one side and again, glued to the wallboard on the other side. In real life, the people who build walls with soundboard leave out the glue. An inner layer of sound deadening board that is not glued into place is just a spacer and an expensive substitute for fiberglass. There are three main reasons for leaving the glue out of sound deadening board wall construction.

1. Most people doing construction don't know that the glue is needed.
2. Buying glue costs extra money and applying it takes a lot more time.
3. Getting glue to stick to vertical surfaces is messy, to overhead surfaces, impossible.

As a result, most people don't even consider trying to install soundboard with glue. And anyone who actually does install soundboard correctly with glue, only does the job once and swears to never do it again.

To properly glue soundboard to the face of the studs and the plates, it must be covered with a zigzag strip of 1/4" panel adhesive. Once the panel is up, the same zigzag pattern has to be applied to the soundboard directly over where the studs and plates are located. Then the gypboard is placed over the soundboard. To apply glue in a zigzag pattern one 10 oz tube of adhesive will cover 24 feet of stud face. The overall glue cost will be at least $0.15/sq ft for a wall with soundboard on both sides. Soundboard itself costs about $0.22/sq ft and if applied to both sides of the wall, the glue, soundboard and tack nail expense is $0.70/sq ft. Add in the basic cost of a gypboard stud wall $0.65 and the glued soundboard version of a sound proof wall has a material cost of $1.35/sq ft. The material cost for a soundproof wall built with soundboard at about $1.35/sq ft is about 75% of the cost of a fiberglass/WallDamp wall which costs about $1.78 per sq ft. Current pricing may vary, but you get the idea.

The fiberglass/WallDamp wall is 1/3rd more expensive than a soundboard constructed wall. And so, one naturally wonders if there is an added value to a WallDamp wall that is worth the extra expense over a soundboard wall. The answer is found in the labor costs to build the two walls. A soundboard wall, built right, takes more than twice as long to build up as a WallDamp wall. The materials cost benefit of soundboard construction is more than made up for in the added labor on the job due to the handling of glue and soundboard. For a contractor who primarily makes a living by selling labor, building a wall that has a lower materials cost but a high labor cost is just good business.

Let's look at the soundboard installation. A pallet of gypboard arrives at the job site. A second and equal volume pallet of soundboard also arrives on the job site. Then one whole layer of 1/2" material, the soundboard, is hauled in, cut up and stapled onto the framed walls. Next, another whole layer of 1/2" material, the wallboard, is hauled in, cut up and screwed down to the framed walls. The labor of laying up the wall boards is twice as high because there are twice as many wall boards being installed. And this describes the standard soundboard wall construction method that doesn't work because the glue was left out of the job. A proper soundboard project includes gluing soundboard to the studs and gluing wallboard to the soundboard.

In addition to the extra labor of working with glue and soundboard, is the consequence of having a wall that is too thick, a full 1" thicker than a standard wall because it has 1/2" soundboard added to both sides of the wall framing. All electrical boxes that mount into the wall have to be the deep box model. Plumbing also has to accommodate the extra 1/2" thick wall surface. Standard door jambs are made for a 4 1/2" thick interior wall and can't be used when the walls are 5 1/2" thick. Here, the labor costs of finishing an extra thick wall again are on the rise.

But with WallDamp, it's thickness is only 1/20" and this causes a negligible increase in overall wall thickness. The installation of WallDamp is simple and clean. Just remove the release paper from one side of the self adhesive sheet and stick it on to the sides of the framing members. The only mess is a few curls of the release paper on the floor. WallDamp installation projects tend to be clean projects. The amount of WallDamp material used to line out a whole room can be held in one hand, unlike the volume of soundboard that is needed. Soundboard occupies 720 times more volume than WallDamp to do the same job.

And finally soundproofing is not only good for the walls, it is good for the floor and the ceiling. WallDamp sticks wherever it is placed and never falls off, even when working upside down.

Material Costs for Wall Construction

1/2" gypboard 4' x 8' 32 sq ft $4.64/sheet $0.14.5/sq ft
5/8" gypboard 4' x 8' 32 sq ft $5.55/sheet $0.17.3/sq ft
1/2" soundboard 4' x 8' 32 sq ft $6.97/sheet $0.21.8/sq ft

Panel Adhesive to glue gypboard, soundboard and studs together, both sides, material cost is $0.15/sq ft.

The contractor price for ready to paint 2 x 4 framed wall that is 8' high and with gypboard on both sides is about $42 /lineal foot. This amounts to $5.25/sq ft wall area.

It costs $2.55/sq ft to build a stud wall in place, labor and materials.

It costs $0.75/sq ft to hang gypboard onto an existing set of studs, labor and materials.

It costs $0.50/sq ft to staple R-11 insulation into the cavities of a stud wall, labor and materials.

It costs $0.60/sq ft to hang soundboard onto an existing set of studs, labor and materials.

It costs $0.60/sq ft to tape and texture a gypboard wall to get it paint ready.

It costs $1.20 to glue soundboard, studs and gypboard together, labor and material

A 2 x 4 wall with R-11 insulation inside and gypboard on both sides costs $5.75/sq ft, labor and materials.

A 2 x 4 wall with soundboard on both sides covered by gypboard costs $6.45/sq ft, and this does not include the glue step but otherwise, labor and materials.

A 2 x 4 wall with soundboard glued to the framing and with the gypboard glued to the soundboard on both sides will cost $7.65/sq ft, labor and materials.

A 2 x 4 wall with WallDamp on the framing and R-11 inside, covered with gypboard on both sides costs $6.25/sq ft, labor and materials.

The WallDamp built wall is slightly less expensive to build than the standard soundboard wall and a lot less expensive than a soundproof version of a soundboard wall, labor and materials.

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