# insulating an 1875 brick and plaster exterior wall



## de-nagorg (Feb 23, 2014)

Close the door and abandon the room until warmer weather, and then either build a new insulated wall, over the existing plaster, or tear out the plaster and build an insulated wall against the brick.


ED


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## pjstock (Jul 23, 2012)

Hmmm, certainly good advice. 
unfortunately the ground floor is just one big open plan, no possibility of closing that back room off.
but spring is just around the corner....


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## jmetrail (Aug 31, 2017)

Is this structural brick or veneer?

Insulating structural brick from the inside is often a bad idea:

http://www.greenbuildingadvisor.com/blogs/dept/musings/insulating-old-brick-buildings

Even if it's veneer, by blowing in insulation, you might be eliminating your rainscreen gap. This gap allows any water that gets in behind the brick to dry before causing mold/damage. If you cram the cavity with insulation, any water than permeates your brick will have a harder time drying (due to age of house, the gap would probably be the only thing protecting the inside of you house from water that permeates the brick - no housewrap back then).

If it's structural brick, I'd be careful about doing anything other than adding an insulated layer to the exterior. If it's veneer I'd probably suggest either building out an insulated wall to the interior (as poster above suggested_, or (probably easier) just add a layer of rigid foam with drywall on top, without actually framing out a wall.

Edit: that was a dumb question. Can see from the pics and your comments that it's structural. Ignore my advice about the veneer - and have a good read through that article for options.


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