How can I tell if my walls are insulated?

[Jaugust124]

Wondering if anyone could clue me in as to when did builders start to put fiberglass insulation in homes?
My house was built in 1971 and I really have no idea how much, if any insulation is in the walls of my house. We have been here just about 2 years. I have been in the attic and there is a great amount of blanket insulation up there which was done in the past 4-5 years in my estimation. There is also insulation in the basement at the sill plate.
Unless I start pulling the walls apart or the window frames how can I tell whats in there?
Thanks.

 

[midwestcoast]

Well, based on the construction date you likely do have some insulation in the walls. Probably fiberglass or rock-wool. I don't know of a way to find out for sure what's in there without actually taking a look. You could try drilling a peak-hole in an exterior wall of a closet, behind baseboard or trim, anywhere else that a patch would be inconspicuous. You could try to look from the outside by pulling out a lap-board of siding (if you have it) & drilling through the sheething beneath & then patch the hole & replace the board.
All of those are going to give you limited info ie. insulated or not, with what, & approx how thick, but won't really tell the whole story about the thermal performance of the walls. For that you'd need an energy audit. If you're really considering adding insulation I'd suggest an energy audit as you'll likely find more cost-effective improvements to make first/instead.
An infrared thermometer can also give clues as to missing or poorly installed in insulation by scanning across a wall on a cold winter day looking for cold spots.

 

[coolidge]

The 1971 building boom featured alot of 2x4 construction therefore you would have an energy saving R11 fiberglass.An energy audit wont tell you what you have just if you have any. Allthough the audit company should have a borascope to check the wall system and answer your questions. I talk to alot of homeowners throughout the year and 90% who say there house was built between 1970 and 72 have 2x4 framing.

 

[EatenByLimestone]

Pull off an outlet cover and take a look around the box. If you have to poke a small hole in the sheet rock it won't be noticeable and/or will be easy to patch.


Matt