I have a house built in 1940's ,the outside walls are solid brick, there is no insulation in the walls. The walls get very cold and damp,where mold forms in the corners. I want to use blow-in insulation, but which kind cellulose or fiberglass ? I hear pros and cons of both. My fear is that celusoe may not hold up in my situation - Any thoughts ?

No form of blow-in fiber insulation will be able to create a vapor retarder, so when moisture migrates into the wall, it will reduce the insulating value of whatever you blow in to nearly zero, and you will still have the risk of mold and structural rot.

Are your walls solid masonry, or do you have a brick veneer over a conventional wood stud wall? If they are solid masonry, there probably won't be space for enough insulation to matter.

You might investigate isocyanurate foam, which will form a vapor retarder, but also investigate the chemistry of the foam to learn what it will outgas into your home.

Unfortunately, the only real good way to insulate an outside wall, if it is a stud wall, is to remove either the inner or outer finish and sheathing. The electrical wiring can also be updated at the same time. Disadvantages: expensive and messy. But it works. Blow in fiber won't work nearly as well, without a vapor retarder.

thanks for the reply, I just know that the outside of the house is stucco, I believe the interior walls do have wood studs. I have had both celusoe and fiber-glass contractors look at it, but no one mentions that blown-in won't work.

Well, of course not. People who are selling things cannot usually be counted on to tell the whole truth. The people who sell inside water diversion systems as "basement waterproofing" are a prime example. Their systems waterproof NOTHING. Next time you talk to one of these people, ask them about a vapor retarder, and how they accomplish installing one. I'm sure they'll tell you they do it all the time without a vapor retarder. Of course, it may take a year for the insulation to accumulate enough moisture to do damage, and it happens gradually, and by that time, ppeople never connect their problems with the insulation installer.

It is fundamental in wall design to install a vapor retarder on the winter warm side of the wall assembly. Without that fundamental component, the problems that it is designed to mitigate against will most likely occur.

I have almost the exact situation. Our house is brick exterior with concrete block as the inside walls and plaster over the concrete. We bought the house two years ago and this is the second winter where we have condensation / sweating walls. I have had insulators out and have been told they cannot blow anything in because there is no space.

I am at a loss as to how to deal with this problem. It is my understanding that moisture in houses is bad and the situation needs to be addressed. I cannot seem to find the right professional to address it. Any guidance and direction would be appreciated.
Thank you!

A couple of questions:
1. What kind of heat do you have?
2. Do you have, and run religiously, kitchen and bath exhaust fans?
3. What temperature is your thermostat set for?
4. Is the condensation universal, or just located in particular spots?

A couple of questions:
1. What kind of heat do you have?
We have gas heat and a newer furnace. (Trane high-efficiency installed in 2005.)
2. Do you have, and run religiously, kitchen and bath exhaust fans?
We have both and run them whenever we are using those rooms. We installed both of those fans last summer.
3. What temperature is your thermostat set for?
Weekdays when we aren't here it is set for 63; evenings and weekends it is on 70.
4. Is the condensation universal, or just located in particular spots?
Particular spots - though it is occurring on both the 1st and 2nd floors. We have been running a dehumidifier upstairs to capture the excess moisture and have been collecting about 15 - 20 pints per day.

When they installed the furnace, Did they install a humidifire with it?
The reason for the condensation as you know is cold spots on the walls allowing the moisture to collect. What concerns me here is that the side of the wall you cannot see is also getting damp or wet. This translates into mold. I would cut a small hole in the wall and see how close the interior walls were placed to the block. You could always remove the walls and place foam boards between the lath if it was all they used. If you had framing, you could insulate in that area as well. There is no quick fix for this.
If your removing that much moisture daily something is wrong. Your home is producing to much moisture.
How dry is the basement? Do you suffer from leaks in that area?

There is a humidifier installed though I do not know if it was installed with the furnace or if it is older. The control panel for the humidifier looks pretty old. Our basement doesn't have major leakage issues, though it is damp and we had been running the dehumidifier down there daily and getting between 20 - 30 pints, depending on how much precipitation fell.

I did have a roofer out to tell me that the dampness isn't related to a leak in the roof, though he said we don't have roof vents and installing them will help. But he didn't feel like that was the entire story, that something else was going on.

I would like to call someone in to help figure this out but don't know what type of professional can solve this. Should I call an architect or a builder or an HVAC person to optimize our settings or some other expert?

Thanks for all the help so far!

Let’s start with the attic and roofing.

When looking into the attic do you see rust stains around the nails that protrude through the plywood holding the shingles on? Go up in the attic after a warmer day and below freezing night. First thing in the AM before the sun has time to hit the roof. Do you see any white ice along the eaves or ice forming off the protruding nails? Look at the floor in the attic or on top of the insulation. Do you see any water stains. Answer yes to any of these questions then you need to address the ventilation in the attic. Do not use power vent unless you have installed a de-humidistat control along with the temp control. It will pull more dampness into the attic and cause more issues then you already have. A good quality ridge vent along with proper soffit vents will help.
Also while up there, If you have (you should) insulation on the floor, lift it up and look under. Is it dark and appear stained? If there is paper on it is it crumbling and falling apart? That is a sign of excessive moisture within the home caused by vapor pressure. More on that later.

Now let’s move down into the basement.

If you have a humidifier on the furnace. and the controls appear to be older. Is the unit working at all? Describe the unit. Does it have a pan inside that a round sponge like drum rotates into it? or is it a square box like unit that has a water line entering into the bottom with a hose coming out in the same area as well. Is there a name on the device? Some of the newer units can place several gallons of moisture into a home in a very short period of time. If your using this type of unit and its not properly set, you could be removing or attempting to remove the same moisture your putting into the air.

Now let’s address the dampness on the walls.

Moisture always seeks a dryer source. What is happening in your case is that the excessive humidity within the basement is making its way up and into the first floor and upper levels of the home. Dehumidifiers can help but they are a control method for moisture not a fix. If you’re experiencing that much moisture within the house, and you ruled out the unit on the furnace as being set to high or not turning off. Then I would look into the following.
Be sure that all bathrooms that have showers have either a fan or window that is used to prevent excessive humidity. Be sure that all faucets are not dripping. That all appliances such as gas stove and dryer is properly vented and working correctly.

Let’s check the basement walls for water entry and moisture source.

We need to determine if the moisture is entering through the walls or floor or is coming from another source within the basement. To do this you will need to do the following. Tape a one foot piece of plastic food wrap onto the wall and floor of the basement. Use duct tape to hold it onto the floor and wall. Let it stay there for a few days. If condensation is forming between the plastic and cement wall/floor you have a water proofing issue and need to address this with a water proofing contractor that does the work on the outside of the house Not in the basement. If it’s on top you have excessive humidity from another source such as a incorrectly operating humidifier or improperly vented appliance. Your HVAC person should be able to assist you on this.
Are there interior French drains in the basement? Does water appear to be running in them or does the sump pump assuming you have one run a lot? Have you experienced water issues in the past in the basement?

We see a lot of homes such like yours. Lots of peeling paint on outside indicates high vapor pressure within the home. You do not see this because you have brick. Over 90% of the time it ends up being basement water entry issues. The basement water can move quite easily through a home and cause a host of issues from what you’re seeing to bugs, termites’ sticky doors etc and ill health particularly to young children and very old adults.

Thanks for this - I need a couple of days to track all of this down. I will repost and let you know what I find out. Please stay tuned!

Hi,

I'm sorry it has taken me so long to respond on this. I hope you are still willing to help me!

Here are answers to your questions:
1. There appears to be rust around some of the attic nails, though I can't tell whether it is recently formed or if it has been there a while. There are also some damp spots / water stains. (Incidentally, we don't have a real attic, just a crawl space that sits above the front entryway.) The floor insulation is not dark or stained.
2. We do have a humidifier attached to the furnace - it is the square box like unit you described. There is no name on the device.

3. We only use one bathroom for showers and it has a new exhaust fan. I believe there are no leaks - is there any way to check for these, other than visibly seeing a faucet leaking?

4.Our basement seems pretty dry. We did the test you described and there was no condensation on or under the plastic. We do not have french drains or a sump pump. We have lived here two years and haven't had any water in the basement issues.

5. Another disturbing thing happened: We found a bubble under the paint in the bathroom, which was full of water. This is on a painted plaster wall. We also had some sweat spots on the walls in our breakfast bump out and ice crystals in the kitchen cabinets.

Again, thank you for any help and advice you can provide.

To wdr.
I think your problem can easily be solved by injecting high density cellulose insulation into the walls. Not fiberglass. High density cellulose does not require a vapour barrier. Cellulose is not subject to the same vapour diffusion as fiberglass as long as it is installed properly, this means at a density of about 3 pounds per cubic foot. This is twice what would typically be installed into an attic. We would install this either from the interior or the exterior. From the exterior we drill a one inch hole through the mortar in the corners of the brick. The cellulose is injected pneumatically and then the holes plugged with a liquid mortar.

I am sure many would disagree with my comments about not requiring vapour barrier. However, the widespread use of vapour barriers is a direct result of the widespread failure of fiberglass insulation. Fiberglass will allow air movement through the wall or attic assembly.Warm moist air is carried to the cold substrate where condensation occurs. Hence the concept of using vapour barriers. The reality of a vapour barrier is that for half of the year the vapor barrier is on the wrong side of the insulation. If you have air conditioning, the vapour drive is now reversed, the warm moist air from outside is trying to get inside the house, it meets the vapour barrier and can cause condensation on the inside of the wall. This prevents the wall from ever drying out completely.

A 2x4 wall cavity will give you a real R value of about R15. The performance is exceptionally good because you have virtually eliminated any air leakage. If there is no air leakage the warm air currents are reduced and consequently condensation does not form.

The attic stains around the nails indicate that moisture has collected within the attic area. It sounds like the attic is not being properly vented or if you have a power fan its not controlled using a humidistat.

You said that you have a exhaust fan in one bathroom. Is the vent going to the outside? or dumping into the attic. Is the pipe of the fan if there is one insulated in the cold attic area?

The humidifier that is attached to the furnace, How is it controlled?

As far as the bubble under the paint. If your getting water like that you have a leak coming in from somewhere. Perhaps built up condensation within the exhaust fan unit or in the vent pipe. I have seen a five gallon bucket fill with water from an un-insulated vent fan pipe located in an attic.

AS far as the sweat spots and ice in the cabinet. It sounds like the builder failed to properly insulate the walls. You can do what Ed the insulator says and blow in cellulose or if it was me. I would remove the wall material after taking photos of the issues and determine why the walls are so cold.
Bump outs often are difficult to insulate as the floor extends over to the outside. The many faming members often are very close together and quite often the insulating contractor fails to properly pack between the joists. Also because the floor extends out air that blows under the bump out is forced into the overhand and often bypasses the insulation barrier.

when I see bubbles in the paint that usually means there is a leak which could be coming from pipes therefore having nothing to do with actual insulation.. you may want to double check that as well before assuming it's part of the insulation problem - -Fishfool @ The Reef Tank