My home office is located on our 2nd floor, adjacent to the attic for our garage. The garage attic has no insulation in the roof deck, floor, or exterior wall, so I'm sure it gets pretty warm in there. The wall between the garage attic and office has batt insulation (see pic); I'm sure the batting continues up to the house attic above the office. So the office gets a little warm in the summer (I'm sure the computers and monitors don't help). The office wall extends further up beyond the garage roof line to full 8' height. My recollection is that the other interior walls of the office are a few degrees cooler on hot days.

Is there a reasonably easy way to improve the insulation of this wall in the garage attic space?

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  • With bare studs it is quite easy to add on to them to increase the depth of insulation. Having/increasing the ventilation in the garage so the heat can escape will help also.
    – crip659
    Commented May 19, 2023 at 14:25
  • 1
    You advised that you have computers and monitors in your office. Understand that no matter how much you insulate the machines will be generating heat. The insulation will help hold that heat into your space. You may want to examine how to better cool the area rather than insulate.
    – RMDman
    Commented May 19, 2023 at 14:29
  • 3
    Or cool as well as insulate. Insulation can help maintain temperature differential in either direction; cooling will be more effective if more insulated.
    – keshlam
    Commented May 19, 2023 at 17:09
  • Do you have any idea how hot the attic above your garage gets? My attic - above a 1 story rancher in the Mid Atlantic - peaked at 123 deg F last summer. If you know that, you can estimate how much heat gain into you office that wall is causing. But 3-1/2" fiberglass seems pretty wimpy between a conditioned and unconditioned space.
    – SteveSh
    Commented Jun 18, 2023 at 18:40
  • @SteveSh I have not attempted to measure that.
    – Huesmann
    Commented Jun 19, 2023 at 12:09

2 Answers 2


Foam sheet would be dubious due to it acting as a vapor barrier in the wrong location, unless your climate is strictly cooling (and if so the assumed vapor barrier if that's not unfaced batt is in the wrong place.)

Additional unfaced batts, held in by net or wires, or net and cellulose blow-in seem like the least effort approaches that should work, here.

If you want more solid anchoring for your new insulation, you could borrow a trick from the "Larsen Truss" wall system, which uses thin plywood strips to space non-structural framing away from structural framing without the full thermal bridge of solid lumber, and then stuff that space full of more insulation.

If ventilation is sub-standard in the attic space, improving that would lower the temperature gradient you're insulating against.

  • The peak of the roof is to the left of the pic, above the MBR. There's space between the truss rafters and the MBR ceiling, and the peak has a ridge vent. The garage attic has eave vents. I could conceivably add a gable vent to the exterior wall (opposite that shown in the photo). Not sure how much that would help.
    – Huesmann
    Commented May 19, 2023 at 20:09
  • Sounds like venting is fairly standard, then, unless any vents are clogged.
    – Ecnerwal
    Commented May 19, 2023 at 20:11
  • Pretty confident the ridge vent isn't clogged, as the roof was redone in November, and I can see the eave vent is clear from the attic. But we have had a bumper crop of maple helicopters this year...
    – Huesmann
    Commented May 19, 2023 at 21:27

Well, I've not really solved the problem, but I've ameliorated it somewhat. Two of the tower computers have been moved down to the basement. Only computer left is the work laptop.

I tried a couple of "over IP" HDMI KVM extenders, and while they kinda worked, it just wasn't good. I do have a gigabit network, but I think those guys need multi-gig networking or possibly consumer grade is insufficient.

So I ran a pair of CAT8 home runs between the basement and office—out the basement wall, up the side of the house (partly tucked behind a gutter downspout) and across a bit, into the attic, and down into the office wall to a keystone jack. The basement end of the cable just got plugged directly into the router there.

These are the extenders I used:

https://www.amazon.com/LornCeng-Extender-Latency-Support-System/dp/B09QBYT2NQ https://www.amazon.com/Extender-Ethernet-Keyboard-Control-Signals/dp/B0891XSPSN

The first one I kept even though it didn't really do "over IP" well, because it otherwise worked well over direct cable and it had an audio port, and does 4K which I needed. The second one I bought because it was inexpensive and I didn't need 4K for the other computer. (I'd bought a third when I was trying to get it to work "over IP" but that one had an annoying idle screen that wouldn't go away when the monitor was supposed to turn off, so it got returned even though I eventually decided to go direct cable—what's the point of having an idle screen?)

Temps are a little cooler now, but there's still a degree or two of temp differential between inside and outside the office. I may revisit additional insulation at a later date, but I can live with this for now.

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