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Should I Insulate My Walls?

I'm getting ready to redo a 2nd floor bedroom in my 1892 balloon framed house. I've read that it is a bad idea to put insulation in the walls, interferes with ventilation and possibly creates a mold problem. I am going to drop the plaster ceiling and vapor barrier and insulate (attic above) and do exterior and possibly interior storm windows.

Should I leave the (plaster) walls be? Heating will be radiant floor, going to rip the floor boards up, do warmboard with hardwood on top (original fir T&G floor is too far gone to save.)



Re: Should I Insulate My Walls?

Insulate! We have lived in several balloon framed houses and you would be amazed at how insulating with blown in insulation cuts the infiltration of cold air and keeps the warm air in. The two typical insulations used are ground up newspaper and fiberglass. You can ge the machine for free from Home Depot rental centers as long as you buy soo many bales of insulation. I've done this myself several times and it is a piece of cake. You need two people - one to feed the machine and one to direct the hose.

Re: Should I Insulate My Walls?

If you live in the North and you use a blow in insulation, then you need to create a vapor barrier on the inside of the insulation. There are paints that can significantly reduce vapor penetration into the wall. You also want to make sure that there is some ventilation of the wall cavity from the outside. Insulation works much better if it is dry.

If you live in the south, then you better treat the wood in the walls with a sodium borate solution before insulating, especially if you use a blow in type. During the AC season, you will be bound to get condensation in the walls. The sodium borate will prevent rot, mildew and mold and it can be foamed into the walls. It will also protect you from termites and other wood boring insects. Two brand names are Timbor and Boracare.

If you don't mind tearing out the plaster and either re-plastering or going with sheetrock, then fiberglass batts or icenene blow in insulation would be the better way to go.

Re: Should I Insulate My Walls?

You can leave the plaster and install cellulose. It is NOT a job to be done as DIY. You need to get someone who can dense pack the cellulose, which is done with a much more powerful machine than what you get at HD. Dense packing involves inserting a smaller diameter tube in the wall and pumping it until it is dense. Sticking the nozzle in a hole, or even two does not pack the insulation tightly. It will eventually settle and if loose, can let air circulate and carry moisture with it. I would put spray foam in the rafters and get a really good seal.

How much is the radiant going to cost? More money in the building envelope is a far better investment.

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