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Plaster Versus Efficiency

I'm beginning the renovation of a two-story historic home built in 1869 in Mobile, AL. The "Croom House" is a landmark on one of the oldest public squares in the city. The house was owned and inhabited by the Croom family until I purchased it from the fifth generation last year. My question concerns the issue of historic preservation versus the value of energy efficiency. The interior walls are all plaster except for the ceilings which were covered in wallboard at some point in the past. Many of the plaster walls are in good shape but others have suffered significant cracking and in some areas, the plaster has turned to a soft, sand-like material. I have been told that I should salvage and repair all of the plaster to preserve the historic nature of the house. But, with the rising energy costs to deal with, I'm having trouble deciding what to do. I would love to be able to replace the wiring and insulate the exterior walls but insulating presents other issues due to the lack of a vapor barrier. Bottom line question is two fold. Does tearing out the existing plaster and lath to allow for insulation, wiring upgrades, etc. offer enough energy savings to offset the loss of the historic value the walls provide to the home? Is there a way to save the walls and still improve the energy efficiency of the home?

Re: Plaster Versus Efficiency

I'd find a way to rewire the house then invest in a closed cell pourable insulation application. I had the same thoughts about the walls in my house. It flooded twice in the mid 80's and the insulation was taken out and the sheet rock replaced. I didn't want to disturb the walls but I wanted to get some insulation in there. I checked with another member, Bay Harbor Insulation, he told me about the pourable insulation.

Okay, I can see that this application won't provide a complete house wrap style moisture barrier but it will help a little. My house is rock so wrapping the outside is out of the question.

Check into it.

As far as the wireing, maybe you could create a chase behind the base boards?

Re: Plaster Versus Efficiency

The National Parks Service has a very helpful series of e-articles (Briefs) on Historic Preservation, several dealing with do's and do not's regarding insulation and historic plaster, paint choices, weatherizing, special considerations for long-term integrity, remediating former mistakes and correcting damages, etc.

They are free and available on the net at the NPS site as well as recreated elsewhere with permission on the oldhouseweb site.

You may find the information helpful. If you have difficulty locating the NPS Historic Preservation Briefs series of articles, please advise here and I'll post direct links for you.

Re: Plaster Versus Efficiency

I would advocate for retaining the plaster. You will not be able to replace the original plaster with anything as good or better. A talented electrician will be able to rewire the house without causing significant damage to the plaster. Additionally I would not insulate the walls on your building. You will only save 10%+/- on your energy bills and you will create moisture problems ranging from rotting framing to peeling paint, exterior and interior from the house not being able to breath by plugging up the passive ventilation designed into this house which has lasted a considerable period of time. Use what ever method you can top cut down the air infiltration, this will save you as much energy and not cost anywhere the amount of insulation.

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