Home Improvement → Insulative Sheathing under aluminum siding ?

I'm planning on blown-in insulation in the wall bays in this old house.

The old Alcoa Alum. siding will be removed to access the original outside wood sheathing, then re-installed.

An so, I'd like ideas for adding some sort of extra insulating material under the Alcoa siding. An estimating contractor believes there is some sort of 'nominal' (some type of thin foam-board) treatment that was originally installed under the siding.

If there exists a good practice for this idea, I'd just as well add it while I'm at it.
I'm a big believer in radiant barriers in attic applications, are radiant barriers OK for this application?

Thanks in advance.

Are you planning on adding Tyvek house wrap?

You may want to use caution on that idea, as anything that makes the house "thicker" could possibly end up meaning your corner trim will no longer cover the edges of the siding at the corners.

A radiant barrier sandwiched between other materials will do next to nothing.

The problem in adding insulation is that the siding will be spaced out from the house and no longer fit as before. I can see problems at corners, windows and doors, etc. The insulation currently under is probably the 1/4" blue board. You may be able to use the bubble wrap type insulation with the mylar reflective sides in place of what is there now. It is about the same thickness but not sure how much insulation value it would add. I have had good results with it in other applications and it is a radiant/thermal barrier.

Well, I do not know. That is why I'm seeking opinions.

Just returning from scouting the outside. I do believe there is some thin (~ 1/2 " ) material that is indeed just under the Alum. siding.
Since the siding has been up for over 25 years I bet whatever the material is , it has no radiant properties (like the modern material i see at the big box stores, with a reflective laminate on one surface).

You need to be aware of the situation robbin and I are speaking of. If you are able to replace the existing material with something newer of the same thickness, you should be OK. Anything that adds thickness is going to cause trouble.

There should be sheathing under most of the siding and plywood in the corners. (If it's like my builder) I did what you are suggesting and had a pro, (using the term loosely) do the job of adding additional board insulation to the house and then siding.

The main problem is that he had trouble fastening the siding to the new double layer of insulation and sheathing. I didn't find out until a few years later when the siding started blowing off.

I think the proper way would be to replace the sheathing with the insulation board.

I am *really* curious as to how they plan on removing old aluminum siding and re-installing it.

I've had houses with aluminum siding. First, I can't imagine why you would want to put it back up. Second, it seems like it would add quite a bit to the cost of labor vs. "rip and rebuild".

I've removed aluminum siding. It scratches, dents, kinks, and "rubs off" (the paint) very easily. It's nearly impossible to get off without damaging it.
We have too much hail around here, so AL siding doesn't really stand a chance. It's not very common. It seems like it was a "70's thing".

Yes what's the plan on house wrap? A properly installed air barrier will do far more for energy efficiency in an old home than an extra 1/2" of insulation could ever hope to accomplish.