I have some rolls of 15" R-13 insulation that I am planning on installing in my floor joists to help sound proof my basement ceiling. Is there anything that the insulation can't touch? I know that the lighting has to be rated to touch the insulation but what about pipes/wiring?

  • 2
    Generally, nothing.
    – isherwood
    Apr 1, 2016 at 14:02
  • 2
    And lighting that is not IC rated needs at least a 3" gap.
    – bib
    Apr 1, 2016 at 14:23

4 Answers 4


It doesn't matter to piping. As a rule, piping likes insulation. Although for cold piping, condensation may be an issue; insulation can hold that water and cause mold and mildew.

It's an issue with electrical, because some types of wire need to be able to cool, and they can't do that covered in insulation, and this has caused house fires.

I am hoping some of the electrical-code experts who know more about this area of practice will chime in.

  • There is no code as far as I know involving electrical wiring and insulation. The whole point of electrical code is to make sure the proper wire is used to be ran through insulation - there is an assumption there. There is however rated electrical devices (pot lights) for insulation and others that have to have a minimum distance.
    – DMoore
    Apr 1, 2016 at 19:03
  • The issue is when the insulation comes after the wiring: insulation is added to existing wire that may not be rated for insulation, e.g. knob and tube. Apr 1, 2016 at 19:41
  • Yep but that isn't code once he makes changes to that space.
    – DMoore
    Apr 1, 2016 at 20:34
  • You're saying adding insulation counts as renovation, which obliges him to bring the electrical to current code. Seems like that would be widely overlooked, but ok - there's his answer. He needs to make sure all electrical in the area is to current codes, i.e. wiring compatible with insulation. Apr 2, 2016 at 2:26

This is pretty late for the op, but for anyone else that comes across this threat.

Resilient channel is extremely easy to short circuit, and there are numerous examples for installs gone wrong with sheetrock falling. You want hat channel with the appropriate amount of clips to actually hold the weight of the sheetrock.

Just a home theatre enthusiast here, but I have used their products in our first house. Check out the soundproofing company website for general guidelines.

  • Pink or yellow fluffy will keep the the joist bays from becoming a drum.

  • Using 5/8 type x sheetrock will give weight.

  • "Hat channel" with the basic clips is all that's needed to break the connection.

  • Double sheetrock with green glue works as a dampener

I like the idea of rockwool instead of fluffy for moisture in our situation, but in a dry space it does virtually nothing better than pink/yellown fluffy insulation to stop the drum situation.

Hope this helps.


Typically you want the basement insulation installed with the paper (vapor barrier) facing the heated part of the home. Moisture from inside air can condense and become trapped in the insulation during cold winter months leading to mold, especially at rim joists or skirts (paper facing outside).

However, if you will be spending a little more time in the basement, you will want to do this differently. You will most likely want to use a foam board toward the house, then turn the insulation over so that the paper is facing down toward the basement. But if you are going to finish the basement and use it as a proper living space (and finish the ceiling with drywall), then you should not insulate the ceiling at all. You'll need to insulate the walls of the basement, and buy some soundproofing foam for the ceiling.

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With all that in mind, cables (wires) should be exposed if possible (keep the wires cool). But pipes are more efficient when insulated (less heat loss).

Oh, and technically, hydrofluoric acid will react with (fiber) glass.

  • 1
    I think if you have open vats of hydrofluoric acid in your home, soundproofing is the LEAST of your worries. That stuff eats almost EVERYTHING. Apr 1, 2016 at 18:39
  • I would like to mention that the only reason I'm installing insulation in the ceiling is for sound proofing. I don't have the resources to use legitimate sound proofing materials.
    – Programmer
    Apr 1, 2016 at 18:52
  • I believe that you can find egg crate foam pretty cheaply... cheaper than replacing wood rot anyway. I hate shopping for people, but here's a pretty good deal: combinationtherapymattress.com/… Apr 1, 2016 at 19:05

Have you considered mounting sheetrock on the ceiling using resilient channel? Perhaps in addition to whatever insulation you put in the ceiling. The resilient channel will hold the sheetrock off of the joists. Since the sheetrock doesn't touch the wood, sound doesn't transmit directly from the framing to the sheetrock. Be sure to talk to somebody and/or watch some videos. You want to screw the sheetrock to the channel between the joists. Otherwise, you'll end up driving screws clear through the channel, into the joist, and acoustically coupling your sheetrock to your joists, defeating the purpose of the channel.

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