What type of insulation is this and should it be replaced?

Question

We opened one wall in an old New England building and found 4 types of insulation. What are the different types and which one should be replaced? Plan is to used R15 mineral wool batts.

No idea what this is. I would replace.
Stuffed newspaper. I would replace.
Old blow-in cellulose. Should this be replaced when the walls are open? Still seems tightly packed.
Fiberglass. I would replace in this condition.

Think hard and long about flammability when choosing insulation. Rockwool doesn't burn at all. Check out this video skip to 4:40. Compartment #3 is rockwool. Bo-ring! — Harper - Reinstate Monica, Dec 09 '22 at 05:55
How about a good high res picture or scan of that newspaper? I love old newspapers found in walls. — Aldus Bumblebore, Dec 09 '22 at 22:49
@AldusBumblebore already removed but it was the Boston Globe from Oct 2, 1981 and (ironically) included an article on energy efficient lighting and home maintenance. — user2503795, Dec 10 '22 at 12:21

score 11 · Accepted Answer · answered Dec 09 '22 at 13:48

It was common in less fortunate times for old clothing and rags to be used as insulation, along with sawdust, forest materials, and many other on-hand items. I've pulled jeans out of walls, along with carpeting and about any other lofty material you can imagine. Whether you should replace it is a matter of climate and budget.
See #1.
Cellulose still performs fairly well even when compacted. If you're redoing the entire wall I'd just pull it out. Otherwise leave it.
Obviously that cavity needs more fiberglass. There's nothing wrong with repositioning what's there to reuse it. Fiberglass hasn't changed much over the decades other than by becoming finer (less itchy), and well-fitting pieces are every bit as effective as a single piece.

score 5 · Answer 2 · answered Dec 09 '22 at 04:50

5

I see some newspaper an old rug some fiberglass and some Styrofoam.

None I would call actual isolation just bits and pieces.

Yes you should definitely replace that.

answered Dec 09 '22 at 04:50

Traveler

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What is with 3 in the picture? I think it is old blow-in insulation still tightly packed. – user2503795 Dec 09 '22 at 05:13
@user2503795 it looks to me like a pice of styrofoam – Traveler Dec 09 '22 at 05:26
no, that’s just the picture. I added another picture that shows the same insulation where it is not as tightly packed. Does it make sense to replace this in the wall? – user2503795 Dec 09 '22 at 12:42

What type of insulation is this and should it be replaced?

2 Answers2