i have a cold attic space that has an interior wall into my living space. What should i have for insulation? I can only access the attic/cold side of the wall. Also, would i use a vapor barrier?

  • Is there any insulation up there now? – SteveSh Jan 27 at 18:59
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    We'd need a lot more detail about your building, climate, etc. before we can help. Please revise to add information. – isherwood Jan 27 at 19:28
  • Are you limited to insulating the attic, or is insulating the roof an option? – ThreePhaseEel Jan 28 at 0:25
  • The first part of your question is opinion base and doesn't fit this site well. If you can come up with a more objective question or wording, it'll fair better – Ack Jan 28 at 0:35

Vapor barrier, if any, on the warm side of the insulation.

Type of insulation is your choice. More is better, within reason. Costs vary - if you have space for it, cellulose is usually the best bang for the buck. The insulations that perform better in thinner sections also cost more per applied R-value. With a wall application, cellulose would need a net, or a second (non-structural) wall to hold it in place.


Use thermal aluminum foil PLUS mineral wool. Those to combined will make you forget about the cold.

  • The foil may not be an appropriate air/vapor barrier in all situations -- there is quite a bit of merit to vapor open "flow through" wall assemblies. Have some more on this topic – ThreePhaseEel Jan 28 at 0:25

The easiest one to apply would be fiberglass bats. Do NOT put a vapour barrier in. Vapour barriers only make sense on the warm side of a wall.

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