foam insulation in solid brick house

Dirk Wright

Maybe you should consider injecting foam between the plaster and the brick? You said you had a 2" air gap there?

A really great book about this is: "Builder's Guide to Mixed Climates" by Joseph Lstiburek, Taunton Press. There's also one for cold climates.

john_58

I have read a lot about foam insulation done to old (historic) solid brick homes with an air space instead of insulation. These homes have been around for generations with very few mold, etc problems. Can anyone tell me if done to save money on heating costs, will it affect the way the original structure breathes. I have one of these 120 year old homes and wonder what the ramifications are. It would probably stop the bats from coming into the basement from the attic though. Thanks.

Ron Schroeder_3

foaming your dead air space

will most assuredly affect the interior climate of your home. When I was certified as an installer of HRventilation equipment, I learned that in olden times natural air changes in a home might exceed 12 per hour. These homes never had reported mold and stale air problems precisely because of the high rate of natural in and exfiltration of air (read draft).

When building codes began to demand that the envelope be tightened due to rising energy costs, the witers of these code revisions did not include the requirement for continuous mechanical ventilation. No one considered that a house had to breathe. Mould and New House Syndrome began to appear. It took a while, but once the HVAC industry began to understand what had gone wrong and what was neede to correct the situation, a whole new industry, HRVs and ERVs, was born.

If you seal off the natural respiration of your home with injected foam, you will keep the bats out. You will also trap the water vapor produced by daily living inside the building and thus compromise the comfort and safety of your home unless you also invest in some form of continuous mechanical ventilation. You may call me at 1-604-533-9445 if you have other related or even unrelated heating and ventilation questions.

Shalom

PM_2

insulation and old houses

There is nothing that makes a house last longer than having no insulation and excess ventilation. The only down side is the massive energy bills. To save energy, you must reduce how the building "breaths", this will change the dynamics of heat and humidity.

- Have a properly designed ventilation system installed (HRV or ERV) that runs 24/7. (these are small units)

- Leave airspace immediately interior of the masonry.

- Stop air infiltration/exfiltration as interior most as possible.

- Use sealed combustion appliances.

- Do not negativly pressurize the house.

With these steps you are a long way to a durable, healthy, efficient house.

john_58

Thanks you both for the input. This is what i suspected. The house is a character/historic house with no ability to run ducts. Beautiful huge old water rads for heat and multiple ductless a/c units to cool/dehumidify. The house is comfortable (no real drafts)but huge and expensive to heat. The space between the lath and plaster and the solid brick wall is only about 2 inches. It appears that we really must let the solid brick wall breathe as well. I've been working on the exterior envelope (caulking, etc) and will probably install TRV's on each rad next summer. For now I keep the modern woodstove stoked and turn down the rads.

Ron Schroeder_3

What is your back-up fuel

when your back says no?

john_58

Sorry? I'm not sure I know what you mean. Wood is just for the woodstove (1 room) and the house boiler/heater is nat. gas 260,000 btu Lochinvar

john_58

Okay, sorry, I get it now. Duh. Well i would buy the wood for about $50cdn /face and have my wife stack it and throw it on the fire. I'll watch with a whisky in hand.

Ron Schroeder_3

do you need all that input

Perhaps if you recalculate your heatloss, now that you have caulked and all, you will find that you can be comfortable with a smaller input boiler.

You might further find that a home with as much heatloss as brick presents is a prime candidate for a condensing boiler. You might be surprised at how quickly the energy you save will pay for the cost of repowering.

Its just a thought...

john_58

Yes I thought of it. In fact I thought maybe two smaller Munchkin boilers set in stages may really save money. Its just that the exisiting lochinvar at 260 was installed in 1998 (still new)by previous owners and the house has 7000 sqft, 3 storeys 9 bedrooms and 11ft ceilings. The darn thing comes on for about 3 min and satisfies demand. But in the really cold weather, it runs constant. Water returning at about 150F. Once again, thank you for you input. This board has provided invaluable resorces for ho's who want to assess before they have they're contractors work.

Mike T., Swampeast MO

In my experience, solid brick homes/buildings (particularly those with triple-wythe walls) have less infiltration than frame structures of similar age. If leaky, look first to the windows and doors.

I honestly wouldn't suggest attempting to fill the air voids with foam. First, this can be extremely difficult and intrusive as those voids are NOT continuous. If triple-wythe, entry points will have to be made from BOTH sides of the wall between each stretcher course.

Rigid insulation against the inside walls is an effective (and as far as I know safe to the structure) way to insulate solid brick. Unfortunately, this can be extremely expensive as it requires new finished walls and all windows/doors must have their jambs extended and trim reinstalled (best) or replaced (more common).

Joe Brix

I remember reading that

wool fiber and cellulous can breath. Problem with cellulous, it will settle if it gets wet. If blown in from the attic, would this not act as a thermal barrier? Insulating the attic and new windows and doors, as said, can make big improvements without any threat to the structure.