blown insulation around water pipes and hvac supply (not an attic)

[ecx]

Hello all. This is the first level of a two story building in Chicago. The exterior construction is split faced block. It was built as mixed use, with office space on the first floor and an apartment on the second. We're using it as a two level home, with the open first floor as a work and entertainment area (music, movie nights, etc). On the first floor, that open room has two soffits, both containing HVAC supplies, and the longer one running the length of the room also contains hot and cold water supply and drain for the second floor. The longer soffit also encompasses the area directly above the bathroom.

My question is: are these areas (i.e., the soffit interiors and the area above the bathroom) candidates for blown insulation? We definitely want to insulate the pipes somehow, as the copper pipes to the second floor kitchen are totally uninsulated, right up against the block exterior, which seems like a recipe for frozen pipes. Additionally, insulation in those spaces will help with the acoustic properties of the room. My concern is condensation from the HVAC supply duct--- I am a rank amateur and don't really understand under what conditions that becomes a problem.

Please let me know if there's any other information (or pictures) I can provide, or if there's a good answer to this elsewhere. Thanks!
-Erik

 

[ICE]

The water pipes that are in the soffit have been through how many winters without bursting? I won't speculate about condensation. If there are light fixtures or exhaust fans mounted in the soffit they might not be rated for insulation coverage....in other words, they can't be smothered in insulation due to excessive heat.

 

[TheCommish]

Insulation do not make heat, and if yo insulate the soffit and the pipe is on the cold side of the insulation = more insulation between the pipe and the interior warm side a than between the pipe and the outside you may have more problems

 

[bill1952]

If as you say the pipes are tight to exterior block, packing soffits with insulation will put pipes outside thermal barrier, and make it more likely to freeze. Unless you're willing to remove and later replace enough soffit to work inside them, I think you should leave them alone.

 

[tmurray]

What we have seen is people building a box of rigid foam around the pipes with an open side facing the building. This allows the space occupied by the pipes to be the same temperature as the building by maintaining the airspace. the remainder of the cavity can then be filled with insulation.

 

[ecx]

Ok, thanks for the perspective all--- will probably just leave it alone for now.

 

[ecx]

Hi again all. I'm worried I did a poor job of describing this, so if you don't mind... Here's a picture of the inside of the soffit. (We opened this part up because of some water damage, though not from a burst pipe.) The supply pipes are not flush against the block, they just run near it for a few inches on the way up to the second floor. For the length of the soffit, they're actually running next to the insulation, and a foot or more away from the block exterior. The HVAC supply duct is just to the right.

Two specific questions, then I'll leave you alone:
- Having seen the picture, do you still recommend not insulating the soffit?
- Should there be insulation in that bay, or foam around those pipes? (Or did they remove it for the reasons you listed above?)

Thanks all, again much appreciated. We've come across enough wonky stuff in this place that we're not assuming anything we see is correct...
-E

 

[bill1952]

I see would cut and put rigid foam between vertical pipes and exterior wall (block). I like under cutting foam a 1/4 to 3/8 all around and sealing that gap with foam in a can.

Blown in in soffits isn't wrong but it would make any future work or repairs difficult. Batts would be easier to remove for work.

A closed cell foam pipe insulation (hollow split foam noodles) is best way to insulate pipes.

Not sure your acoustical intents - isolation of first from second floor? I made my living planning buildings for the performing arts and pretty familiar with construction for acoustical performance. Feel free to message since not really code.

 

[ecx]

Great--- thanks for the info (and for the second look). The foam noodles were what I was planning on using.

About the acoustics, the goal is absorption in that same room, rather than isolation between floors. I was essentially was hoping to use the soffit as a big bass trap, with rigid fiberglass on the front/bottom to eat frequencies too high to penetrate the drywall. Sounds like pink batts under the pipes would work.

-E

 

[bill1952]

I think absorption within the room would be much more effective than absorption behind drywall.

 

[ecx]

Oh absolutely--- there will be plenty of that too, this would be in addition. Would just prefer to utilize the empty space, all else being equal.