How to Do an Insulation Retrofit on Your Home

Need to fortify your homes' walls? Mike Holmes tells you how.

Mike Holmes offers cost-effective options for insulating plaster and lathe walls

I have a 1950s bungalow with no insulation in the plaster and lathe walls. Is there a cost-effective way to blow insulation into the walls or am I better to spend my money elsewhere? – D.C., Vancouver

The most cost-effective and best way to insulate plaster and lathe walls would be to insulate from the outside of the house. I would recommend using foam insulation and stucco by Durock. Durock has a “puck system” that allows for airflow behind the wall. It also cuts down on mess and you won’t have to move out of the house while you are doing it.

However some people may not like this because it will change the overall look of your house. For example if you had a brick house and you wanted to keep the look you would have to rip out the lathe and plaster and replace it with dry wall. While your walls are open you could add insulation. I recommend closed cell spray foam since it is its own vapour barrier. If you decide to do this I would recommend you getting a sample of this tested to see if there is any evidence of asbestos in the plaster.

You could also drill holes and apply a cellulous application inside the wall. Some spray applications are harmful and in some cases have been banned. Basically, not very good. Another disadvantage is that you don’t really know what is behind the wall and you could be covering over important elements like electrical wires, plumbing etc. So, I’d advise you in this case to open the walls up and see what condition the wiring and framing is in. It’s a great chance to make sure your house is safe and sound.

Mike Holmes (Holmes on Homes, Holmes Inspection) appears on Canada’s Handyman Challenge, Tuesdays at 10pm ET/PT on HGTV Canada.

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