Do you report the probable absence of wall insulation...

… in an old home?

In a balloon frame house, wall insulation is nothing more than an air filter.

Advising your client to add wall insulation would be the equivalent of putting a band-aid on a heart attack.

Actually blocking wall cavities in a balloon frame would help stop spread of fire (with blocking of course)…

As to the above question I pretty much have the standard “upgrade is advisable at some point in the future”.
It is rare you see much of it in the cavities, and we never assume right?

Blowing in dense cellulose…not for its R-factor, but for the sealing effect…might make some bit of a difference, but your average older home with an R-38 or better ceiling/attic insulation blanket will still be exchanging enough air to make sealing the conditioned space within the house from the attic the primary target before wasting money and time on the walls.


These older homes performed properly without insulation and could breath to help prevent any moisture problems.
Were they energy efficient, No.
Insulating some of these homes with blown in insulation might cost you something like $4000 and the payback will be about $200 a year. My math ain’t that great, but would not like to wait that long for my money savings back.
Insulating the walls, leaves many voids when using blown in insulation and does not provide a vapor barrier to protect the exterior wall assembly.
That could cause more problems then leaving it the way it is.

Consider adding insulation in the ceiling areas where it is accessible, and airsealing in as many areas as possible to eliminate drafts and energy loss in the wrong direction.
If upgrades were to be done, on the interior, then at that point insulation and vapor retarder could be undertaken. :slight_smile:

Gentlemen, Gentlemen!!!

Too much old, theoretical standard book learning being bantered about here!!

My first use of my RETROTEC blower door in 1981 was to measure the reduction in air leakage in a house we were blowing walls with cellulose at normal densities to prevent settling and not a dense pack installation. The air change reduction at 50 pascals pressure differential (equivalent to velocity pressure of a 20 mph wind) was 39%.

If you’re not heating/cooling and then losing this amount of air through the thermal envelope, you have a substantial savings in HVAC costs, let alone the savings given by the insulated walls.

Yes, airsealing is the better payoff when considering the $$$ invested versus the savings gained. If you invest $200 in airsealing materials and do it yourself, you may get $300-$500 savings per year. Great payback!! If you pay a retrofitter $1,200-$1500 to do the same work, the returns aren’t as good but still worth it.

In a balloon framed house, it is not cost effective to open up the main floor ceilings around the perimeter to do the best airsealing job at the floor joist cavities that are open to the wall cavities…there’s where the blown cellulose comes in- it’s not perfect but sure beats having nothing in the walls reducing air flow into and out of the floors.

A few years back, did an old 2 storey schoolhouse (1850-1870’s) converted to over/under flats by an architect. She lived upstairs. There was no insulation in attics and walls. Little airsealing was done.

At the end of the first winter after retrofit, her oil company called her to ask if “anyone still lived in the house?”. The bills went down that much that they had to call.

At the end of the second winter, they called to tell her they were taking her off the automatic fill-up plan they ran…sometimes the units took so little oil, that they were losing $$$$ going to the house…“Call us when you need oil!!”

If the walls in most houses are properly checked (simply with a bent piece of coat hanger and a plumb bob), missed cavities will be easily less than 2% or with a really good crew, 1%. In the first year I ran a retrofit company (1980), we brought in an engineer with IR from 200 miles away to scan 4 sets of walls of houses we had (1) problems with filling cavities (due to doubly plastered stud cavities) or (2) the clients demanded IR.

After the end of the process, he approached me with the completed IR reports and asked how we checked our walls to find cavities…all houses were over 99+%, which surprised him. He had a $40,000 AGA Thermovision 700 series unit. I went over to my truck and brought back my bent piece of coat hanger and my plumb bob- a piece of string wrapped around a small stick with 1+1/2 inch nails taped together on the end of the string…you should have seen his face!!

One of the clients demanding an IR scan was my former university chemistry prof- a Brit. I had told him that one area my men had a problem with was a sloping cavity stuffed with old potato sacks as backing for a plaster repair around the retrofitted (an 1860’s house) plumbing vent stack. That showed up but my men were otherwise perfect with coverage.

He had retrofitted the original rear extension kitchen himself. I asked him if he wanted it scanned. His work (with the walls opened up) showed mediocre with many dark cool spots where he had compressed batts behind electrical boxes/wires and where his cuts of the fiberglass batts left gaps in cavities when installed. He felt a bit sheepish!!

The savings in houses with regular qualities/dimensions by blowing walls will be in the 10 to 20-25% range, depending on the style- a large rancher will have a lot less wall heat loss area percentage in relation to a square or compact rectangular full 2 storey house. The 2 storey house will have the higher savings due to the large wall area.

As to the need for vapour barriers, see this published in 1976:

Here’s an excerpt from that digest that changed my way of looking at things when I read it way back then!!

*“Air leakage is now considered to be the prime cause of most condensation problems in walls and roof spaces. If, therefore, a building can be made tight against air leakage it may not need a vapour barrier, as defined. On the other hand, if there are openings that permit air to leak from the warm side to the cold side of the insulation, adding a vapour barrier (even of zero permeance) that does not seal off the openings will be useless.” *

I almost ALWAYS comment on the lack of insulation. If there is cost involved in heating (not so much cooling in my area) or adding insulation, I comment. I comment if I am unable to determine what is insulated or not. I look for drilled holes to see if it was pumped in, I look down the walls from the attic, and sometimes I look in the basement/crawl up the walls. I DEFINITELY comment if I see even one live Knob and tube wire, telling them to remove ALL wires before adding insulation.

I just added this statement to my header in the Insulation section of all my reports:

“We do not comment on the amount or type or the presence or absence of insulation in finished spaces, such as walls.”

For those of you that said you do report the probable absence of insulation, how do you make the determination that it might be absent?

At what age would you call it out?

How would you know whether or not it had been blown in later (say the house now has vinyl siding)?

Where do you stop. Isn’t the inspection visual per most SOP. Who knows what cannot be seen. The house will probably fall apart or sink into the ground one day. Do we report on that?

Exactly Richard.

One should follow the SOP rather than guess on probabilities.

It would be probable if the house is pre-1960,

if there are no plug holes in the exterior wood clapboards

if there are no signs of home improvement

if the house is original

How do you know for sure that the walls are void?

Remove wall plates and check with a hanger wire along the electrical box.

Cut a hole in an exterior wall closet with a hole saw.

Remove a piece of siding, and cut a hole in the sheathing boards

Use an IR camera to verify

Go in the attic and look down the stud cavity

Go in the basement and drill a hole up the stud cavity.

Do any of you want to go through this exercise to know for a fact there is no insulation in the wall? I don’t.

Unless it is factually verified that the walls are void of insulation, everyone is guessing by even saying it is probable.

If there is no evidence during the inspection that the walls have been filled with blown in insulation, recommend that it be verified by a qualified contractor in that field.
These balloon framed houses had fire blocking in the walls, and knowing exactly where to look for port holes that may have been made to insulate them is a trick of the trade. Sometimes the would clapboards are removed and re-installed.

Follow the SOP and move on to the next.
I was paid for the condition assessment and not verifing wall insulation.
I don’t guess, but will charge for investigation of a material or lack thereof.

Hope this helps. :):smiley:

If for any reason the answer is not obvious to me, I comment that I was not able to determine if insulated and what type. I do not drill, or remove pieces of the house.

Most old home here are made either Slump Block or Concrete Block, the walls probably have better insulating qualities than new homes.

But never really gave it much thought about it before. I will consider it in the future.

*By Charles Ostrander & Jonathon Satko

[size=]There is a story of a young architect today analyzing a building constructed in the 1950s with solid masonry walls and single paned glass used on the exterior of the structure. That young architect referred to the building as an “old, masonry, energy inefficient building.” In the present context of the 21st century, it is not energy efficient using today’s standards. But, when it was built, as with most other buildings at that time, very little insulation was used because energy was a cheap commodity and architects and owners did not require use of insulation in their building envelopes.
Insulation and other techniques for energy conservation are coming to the fore today. Therefore, masonry buildings and other building types have been upgraded with different types of insulation strategies. The use (in the 1950s and 1960s) of zonolite, vermiculite and perlite was used initially in the cores of concrete masonry units and wall cavity’s to increase the masonry’s marginal thermal performance. This satisfied the increased energy demands. In the earlier part of the 20th century, some insulation materials utilized on the inside of ice houses built in Chicago were horse hair and cork.

Concrete Block - Normal wt. 8" empty core–1.11 - 0.97
R value of an 8" CMU is only about 1.11

Slump Block
The spirit of the Southwest is unmistakable with Slump Block. This block maintains the same basic standard dimensions as regular units. To give slump block is character, the mix “slumps” when removed from its mold. Because of the unpredictable roll in texture when removing the block from the mold, units take the appearance of hand made adobe.

Slump block is available in a variety of colors and in some cases, colors can be customized for larger orders (construction of homes or commercial buildings). Slump block is a normal weight hollow load bearing concrete unit. Units are commonly available in 4", 6", 8" and 12" widths with 4" (most common), 6" and 8" heights.

Thanks for the education. Never heard of slump block until now.

Aren’t you required to under your State Law?

The problem with your question is “Probable”.
You do not need to be reporting on anything you don’t know about.

There is insulation.
There isn’t insulation.
You can’t access to determine the insulation.

That’s it!
It doesn’t matter how much, how well it’s working, what type it is. Nothing!

These are from Tuesdays inspection, taken in the basement looking up.

Grant inspection 046 (Small).jpg

Grant inspection 047 (Small).jpg

I should add that when I got into the attic this is what I found. Pretty easy to determine that there is no insulation in the house.

Grant inspection 050 (Small).jpg

Grant inspection 051 (Small).jpg


pre 1940 or so home Peter?? Lathe and Plaster??