Soundproof a Ceiling

Neighbor noise through the ceiling if one of the single biggest complaints people have in a multi-family dwelling. Ideally you would treat the floor above, but if you're reading this article, chances are you are not on great terms with the neighbors upstairs. Adding extra drywall should help, but for best results, you'll need to take out the existing drywall and install a multi-stage setup. Both methods are achievable as a do-it-yourself project.

Steps

Adding Extra Drywall

  1. Understand this method. This is a middle ground approach, moderately effective and relatively easy to install. You can expect it to add roughly 6 to 9 "STC points," reducing loud conversations to indistinct speech or murmurs.[1][2] If you're trying to block music and other loud noises, decouple the ceiling instead.[1]
    • Use the decoupling method for concrete ceilings as well.
  2. Install insulation if needed. Drill a quarter-sized hole in the ceiling and look for insulation. If none is present, Blow-in-Cellulose-Insulation or medium density fiberglass insulation.[1] There is no need to repair the holes afterward, since you will be installing new drywall underneath.
    • Do not install new insulation if there's any old insulation, even if it's worn out. The old insulation will prevent you from blowing in new insulation evenly.
    • Avoid foam insulation and expensive "extra dense" products. These can make low density vibrations worse.[3][4]
  3. Apply damping compound to a new drywall sheet. "Green Glue" or another damping compound will reduce vibration between the two layers of material. Apply it to the back of a new sheet of drywall, according to label instructions.
    • ⅝" (15.9mm) drywall is recommended, since extra mass blocks more sound. However, if the existing drywall is ⅝" thick, choose ½" (12.7mm) sheets for the new layer. Different thicknesses resonate at different frequencies, so two different types will block more sound.[5]
    • You can buy pre-dampened drywall, but this is expensive and no different from what you could make yourself.[6]
  4. Install-Ceiling-Drywall. Screw the drywall to the underside of your ceiling. Try to keep the gap around the perimeter as small as possible.
  5. Fill all gaps with acoustical caulk. Even a narrow gap around the perimeter or ceiling fixture can let a lot of noise through. Before choosing an acoustical caulk, read the label carefully:
    • Confirm the caulk is suitable for use on your materials.
    • Check whether you can paint over the caulk. If not, make sure the color matches your ceiling.
    • Consider a fire-resistant caulk to prevent spread of fire between floors. This may be required by your local building code.
  6. Wait for the compound to dry. The damping compound is a major part of this installation. It may take ten days or more for the compound to cure fully and reach its final soundproofing qualities.[1] Check the compound label for a specific time frame.
  7. Add an additional layer if necessary. If soundproofing is improved but still not ideal, consider repeating the process. A third layer of drywall and damping compound can make a significant difference.[1]
    • If the room is not noticeably more soundproof, another layer is unlikely to help. It may be more effective to treat the ceilings in adjacent rooms, or to soundproof the walls.

Decoupling the Ceiling

  1. Remove-Drywall. The current drywall is in direct contact with the ceiling joists. This allows sound from the floor above to pass directly through the joists with little resistance. Once the old drywall is removed, you can install a new ceiling with an air gap between it and the floor above.
  2. Reinforce the floor above (recommended). Decoupling alone is very effective at reducing the sound of conversation and high-pitched noises, but it can make low frequencies (such as stomping feet) sound louder! To get the best of both worlds, apply damping compound to a new sheet of thick drywall and screw it onto the subfloor from below.[7]
    • See above for detailed instructions. Take care not to use screws that break through the floor above.
    • Alternatively, complete the rest of this method first, then reinforce the new ceiling with a second layer. Reinforce both ends if extreme soundproofing is required.
  3. Install insulation between the ceiling joists. Standard R19 fiberglass insulation is just as good as the more expensive "acoustic" insulation. Fill the gaps between the joists, but avoid over-compression, which can carry vibrations through the floor.[5]
    • Cellulose, mineral fiber, cotton, or polyester are effective alternatives. Do not use foam insulation.[3]
    • If you choose the floating ceiling joist approach (see below), install the joists before you insulate.
  4. Consider floating ceiling joists. This is the most effective decoupling method, but may not be feasible if the ceiling space is taken up by ductwork. To do this, install a new joist between each pair of ceiling joists. The new joists should extend 1–2 inches (2.5–5cm) further down than the original joists.[5]
    • Ideally, the floating joist can rest on the inside layer of a decoupled wall. This creates another air gap between the joists and the outside layer of the wall.
    • If you choose this approach, you do not need to follow the rest of the instructions. Just install more drywall over the joists, then fill in the perimeter with acoustic caulk.
  5. Purchase hat channel instead. Installing hat channel (furring channel) and sound clips is less effective than floating joists, but uses less vertical space. For best soundproofing, choose furring channel marked "087F125-18" or confirm that it meets these specifications: ⅞" (22.2mm) depth; 25 gauge; hemmed long edge. Twenty gauge channel is more common, but significantly worse for soundproofing.[8]
    • Alternatively, you can purchase resilient channel, which is designed for soundproofing. However (at least in North America), resilient channel is not standardized, so it's difficult to guarantee it will work.[9] Read customer reviews before purchasing.
  6. Install the hat channel perpendicular to the joists. Install the channels no more than 24" (61cm) apart, and position the end channels within 6" (15cm) of the wall. If there is a vent in your ceiling, end the channel flush against the frame of the vent on either side. Place additional short lengths of channel on either side of the vent to increase stability.[10]
    • If the channel is not long enough to reach across the ceiling, overlap channel lengths by at least 6" (15cm) and screw together. Do not install sound clips onto overlapped areas.
    • Place the channels within 16" (41cm) of each other if you plan to support a triple layer of drywall.
  7. Screw in resilient sound clips. Hat channel alone is not very effective, especially under non-dampened drywall.[7] Install soundproofing clips through the hat channel as follows:[10]
    • Place clips around the perimeter of the ceiling, within 6" (15cm) of each wall.
    • Fill in the first channel with sound clips spaced 48" (122cm) apart.
    • For best results, shift the next row's sound clip placement by 16" and fill it out, spacing clips 48" apart as before. Repeat the shift for each row. To save money (using about 10% fewer clips), arrange clips in a grid pattern instead, using the same positioning as the first channel.
    • See your clip product instructions for how to fasten. Avoid over-tightening, which can reduce soundproofing.
  8. Install drywall over the channel. Install drywall sections perpendicular to the channels for maximum strength. Fill in gaps around the perimeter with acoustic caulk.
    • Applying damping compound and adding a second layer of drywall is recommended, especially if you did not reinforce the subfloor above.



Tips

  • Ceiling ducts can conduct noise between floors. If possible, replace rigid duct with flex duct and install it along a curved path. For a less expensive solution, install duct liner instead.[11]

Warnings

  • Take care that you use screws to attach drywall to the track. Always follow local building codes.
  • Penetrations in the drywall can compromise your efforts. Ceiling can lighting, ceiling fans, and certainly ventilation ducts can leak sound out of the room.
  • Soundproofing materials are often labeled with an "STC" rating. This rating does not take into account bass frequencies or very high frequencies (below 125Hz or above 4,000Hz).[2] Do not rely on this rating if your main concern is thumping feet, traffic, or other low noises and vibrations.

Related Articles

Sources and Citations

  1. ↑ 1.0 1.1 1.2 1.3 1.4 http://www.tmsoundproofing.com/soundproofing-existing-rooms-walls-ceilings.html
  2. ↑ 2.0 2.1 http://www.soundproofingcompany.com/soundproofing101/understanding-stc/
  3. ↑ 3.0 3.1 http://www.soundproofingcompany.com/soundproofing-articles/foam-or-fiber-insulation/
  4. ↑ http://www.tmsoundproofing.com/effect-of-insulation-in-the-common-wall.html
  5. ↑ 5.0 5.1 5.2 http://www.soundproofingcompany.com/soundproofing101/building-a-room-within-a-room/
  6. ↑ http://www.soundproofingcompany.com/soundproofing-articles/building-soundproof-drywall/
  7. ↑ 7.0 7.1 http://www.tmsoundproofing.com/decoupling-explained.html
  8. ↑ http://www.soundproofingcompany.com/soundproofing101/furring-channel-with-resilient-sound-clips/
  9. ↑ http://www.soundproofingcompany.com/soundproofing-articles/is-resilient-channel-appropriate-for-sound-isolation/
  10. ↑ 10.0 10.1 http://isostore.com/guide/how-to-install-resilient-sound-clips/
  11. ↑ http://www.soundproofingcompany.com/soundproofing101/flanking-and-indirect-sound-leaks/
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