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Insulated Wall Construction Interior Insulation Retrofits Masonry




Hence, when the back of the masonry drops below these temperatures (which are likely during cold weather) condensation would occur if airflow behind the masonry were to occur.

In practice, installing batt between studs with no backing is very difficult, and it is almost certain that the batts will not be properly installed.

Hence, this scheme suffers from a number of limitations – it does not provide a reasonable level of insulation, it increases winter time wetting during the coldest weather (the same period during which there is a risk of freeze-thaw damage) and creates a mold and indoor air quality risk.

Hence, interior finishes will be protected, water will not run down and collect at floor penetrations. The empty studs space is ideal for distribution of services and allows the easy application of a drywall finish. In general the interior layers should be chosen to have the highest vapor permeance possible while also avoiding wintertime diffusion condensation wetting. For thin layers of insulation, a semi-permeable foam such as extruded polystyrene or unfaced polyisocyanurate can be used, but for thicker later the more permeable expanded polystyrene board are preferred. 

This prevents any localized water leakage from penetrating and collecting at floor penetrations. The foam boards should be attached with serpentine patterns of adhesive. When the structural connection is via concrete slabs, the there are no real durability concerns. Providing ventilation to this space is almost certain to cause condensation, not avoid it. If exterior repairs and re-pointing cannot control this type of rain leakage, a drainage space may be necessary behind the load-bearing masonry. As the air next to the insulation layer is very dry, it allows highly vapor permeable open-cell foam to be chosen and encourages evaporative drying to the interior.

However, it is chosen on occasion because it also allows the most inward drying and changes the moisture balance the least of all options. The author and the publisher of this article have used their best efforts to provide accurate and authoritative information in regard to the subject matter covered.

The author and publisher make no warranty of any kind, expressed or implied, with regard to the information contained in this article.
If you have tall parapets, they get twice as much rain and no heat flowing from the inside — especially if the parapet is tall.

Maybe there is some metal flashing on the window sills from the last time the windows were replaced, and all the flashing does is direct water to the ends where it dribbles on the walls.

The rain landing on the coping directed all of the water to the outboard edge, which ends at a mortar joint. But once it was insulated, the building had bad freeze/thaw damage in just two years. You can test the brick to quantify the point at which the material fails. Don’t assume that all of the bricks in your building are identical. Moreover, less energy is available to help them dry out.
If steel corrodes, it expands — and that is a problem.

You can inject the wood with borate salts to preserve the wood. You can install hot water pipes to heat the end of the beam. Most people assume that you need thicker insulation in a cold climate than a warm climate. In general, brick buildings in cold climates get less insulation than buildings in warm climates. To determine how thick you can go, you’ll need to talk to your consultant. Some energy experts have insulated old brick buildings on the interior with cellulose. Dry cellulose insulation was then blown into the 4-inch or 5-inch cavity at 3 1/2 lb. I make sure that the wall is pointed and in good repair,” she wrote. Straube prefers closed-cell spray foam. If you own a building with low risk factors, you may decide to go ahead without hiring a consultant.
Even when used with a good vapour check on the interior?

It will allow the wall to dry to the inside, will closed-cell spray foam allow this? That’s because it plugs the cavity behind the exterior bricks. So stay away from this method if you have rain in the day with freezing at night.
The problem has more to do with air leakage and air convection than vapor diffusion.
Also perhaps cellulose has worked (as mentioned in the article) as it has vapour resistivity between mineral wool and closed cell foam. Rigid foam boards can be used to insulate the interior of a brick wall, as long as the seams between the sheets are carefully sealed with caulk, canned foam, or tape.

Cellulose insulation differs in two important ways from fiberglass batts: dense-packed cellulose does a much better job of limiting air infiltration than batts, and cellulose is hygroscopic.

Is it feasible to mix the cellulose with say, a paddle mixer in a big bucket, adding water and then apply it by hand, a bit like rendering/harling/plastering?

Insulating the interior of a brick wall is tricky. My advice is to hire an insulation contractor experienced at insulating brick walls.
In the end, the deciding factor should be the cost and life-cycle assessment for your options.
The typical brick veneer wall is non-structural. If any insulation contractors are installing spray foam in the drainage gap of brick-veneer walls, they are making a mistake. This method has too many detailing requirements to leave to a contractor. I think the spray method (‘liquid applied’ as you referred to it) is great as it as it would ensure a full fill. My main reluctance to use sprayfoam is the risk it poses to joists / timbers embedded in the masonry. I feel cellulose may buffer the humidity and help move water away from the structural timbers to avoid them rotting. Couldn’t you minimize the amount of moisture penetration by using a silane/siloxane water repellent?

That would allow the brick to dry to the exterior while preventing moisture intrusion.
Plus fantastic thermal behavior in the summer with the added mass.
The roof is steep and has gutters but the bricks are pretty soft. Interior is plaster directly on the brickj and the basement is dry.
Eric asked above about silane/siloxane water repellent. Each lime wash application lasts only for a few years, but it is said to improve the hygrothermal performance of the wall.

I would still be a little wary of adding too much insulation, as there can be prolonged periods of wet winter weather, especially the last few years.

Many times, it’s the installation and flashing detailing, etc. I will personally be looking into mineral wool open joint rainscreen on the rear / side where the street presence isn’t as important to the block conformity.

Any articles on insulating attic spaces?

I will not insulate the walls, only the ceiling and overlap the vapor barrier a few inches with the wall. Roxul is a bad choice because it is air-permeable. It’s impossible to install poly in a way that is totally airtight — and in any case the trapped air would inevitably have moisture in it anyway.

Even if the work is perfect, you still have thermal bridging through the rafters.
Would you for see any problems with this method?

Choosing the wrong repointing mortar is one way to damage it.




Category: General Masonry, Brick Walls, Bricks Installing
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