GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Correcting my poorly done semi-conditioned attic

user-7082051 | Posted in Energy Efficiency and Durability on

 I have a 1941 house that was moved onto its current location in the 70’s. Here, we have remarkably high water table and the moisture stack effect is something I will be addressing. I will do the covering for the moist dirt floor in the crawl space to reduce rising moisture. Currently the crawl space is at 70 % humidity.

I am removing all the fiberglass insulation I previously put in the rafter bays and too far out to the top of the walls because we get condensation on the boards. Not good. And I failed to previously put in soffit vents and baffles.

I had thought that I’d have less mice in the insulation too by putting it in the rafter bays…but they have tunneled into it anyway. Dang mice.

It would be great to blow in cellulose but I am concerned about mice and  moisture rising up through the cellulose.  I am thinking about trying to cut and cobble rigid insulation to allow for a central attic conditioned space with venting up the open rafter bays and some kind of insulation out under the lower roof lines towards the eaves. 
I don’t see how to get above R-13 or R-19 out where the roof slopes down because of tight space. Is that Ok?
Also, I am having difficulty understanding what to use for a vapor barrier to reduce the amount of moisture traveling up under the roof deck.
The good news is I am getting a new roof ( hail damage) in 2014.  I just want to engineer the ventilation, insulation, condensation, right this time around.
The roofer advised on roof slope ventilation because of my limited soffits.
Any considerations with this?
Many thanks for anyone’s input.
Rachel

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

  1. frasca | | #1

    If you're doing a new roof, why not put the rigid foam boards above the roof decking?

  2. Peter Yost | | #2

    The order of operations to improve the moisture and energy performance of a building is:

    1. manage moisture FIRST
    2. manage air leakage SECOND (and managing air leakage manages both the flow of heat and moisture).
    3. Manage conductive heat flow (insulation) LAST.

    Peter

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |