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Community and Q&A

Insulating from the outside

ToddFurlong | Posted in General Questions on

I have an old house. Apparently there was an addition added onto the main house at a later time. The insulation is very poor in this particular room. I also will not be able to add any type of insulation to the interior side as there is no wall cavity — the interior walls were built with logs halves. So blown insulation or fiberglass bat insulation will not work for this scenario. (attaching picture of when I replaced the window so you get better idea of the interior side)

The exterior of this room has painted cedar wood siding.

I plan on replace all of the exterior siding on this room anyway so while I’m at it, I figured I should do something to help the insulation…

What would be the best way to insulate this room from the exterior without the use of rigid foam. There does not seem to be any room to add rigid foam on the exterior side without making a lot of design changes. 

Is there some kind of insulated house wrap with R-values? The house is located in New England. 

I’d appreciate any insights or recommendations. Thanks

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  1. brian_wiley | | #1

    I’m unaware of any products that’d allow for insulation without adding dimensional thickness to the exterior. That’s the very nature of insulation I suppose. Resist the temptation to believe some of the claims manufacturers will make relative to the supposed R-values of thinner insulation. The foil faced bubble wrap comes to mind.

    If it were me, I’d focus air sealing instead. It’s hard to make any recommendations as to how without knowing what the outside assembly looks like though.

  2. Expert Member
    Akos | | #2

    Generally adding 2" of rigid insulation on the outside can be pretty simple espcially since you are replacing windows. A bit of trim around the edges and bottom helps hide the thickness.

    2" of foil faced poyiso with the seams taped would go a long way to air seal the room and greatly reduce the heat loss. It won't meet code but you'll cut your heat losses through your wall by about 2/3.

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