Case of Study

As you may know, brick walls cover up to 70% of most houses built in 1970-1980, and overtime, mortars will begin to crumble and weaken due to erosion. They erode by continuously being naturally expanded and contracted through water infiltration and evaporation between small spaces. As the mortars erode, small cracks and holes will open, allowing external temperature to invade houses. This results in an enormous lose heating and gases during certain seasons.

In addition to invasive external temperatures, water will flow through and damage brick walls, causing frosting during cold seasons, growth of fungus from condensation, black molding, and various others problems.

Cold/Hot air are constantly passing through the brick walls, the faster “natural air” fills up the house, the more often it will kick on the furnace/air back on again! Which is cost $$$.

Building Science

Many aspects of a build design can affect the health and comfort and people in the house. There are 3 particular areas that are focused on:

  • Heat Flow
  • Moisture Flow
  • Air Flow

People explore the issues, causes, control measurements, and the effects on both the house and its occupants.

Air Flow

Air needs an opening to flow through, and there must be a driving force to move it. Many factors control how air flow can affect a house. In order for air to flow in, or out of, there must be either a hole or path. Air flows within are either controlled, or uncontrolled, but the actual flow of air is determined by hole size, resistance to flow, pressure effects, etc.

Controlled and Uncontrolled Air Flow

Controlled air flow is usually generated by a machine and is designed to help ventilate air throughout a house. Ventilation systems such as vents, fans and heat/air conditioning systems are examples of machines that can control air flow.

Uncontrolled air flow has nothing to move into or out of in a house. This can be caused by wind, heated air rising within the house, and etc.

Limiting Factors to Air Flow

 The amount of air that flows through a hole is limited by 3 factors:

  • Hole Size
  • Magnitude of pressure across the hole
  • Amount of time the pressure is present

Air will always flow from a high-pressure to a low-pressure area, just like water running downhill. Without an effective barrier, air outside of a home with high pressure will always attempt to entire the home, and if air is inside of a house with high pressure, it will attempt to exit the house into a lower pressure area.  

In short, bricks aren’t waterproof. Even modern homes that are built with cavity walls and largely impermeable materials can still be affected by water coming in from outside, hot air, and cold air as well. Damp and excess moisture within brick and stonework can lead to internal damage and the dreaded black mould

Stack Effects Diagram

Remember, the sum of the air loss equals the sum of air gain

Air Analysis

Roughly 35%-50% of all heat loss in a home occurs through the walls. This generally happens through conduction or physical contact, as the walls of a home are in physical contact with the colder temperatures outside. The heat energy inside your is primarily transferred by conduction through the walls.

Air Analysis

Air loss through the roof up to
20%
Air loss through the walls
50%
Air loss through the draught doors
10%
Air loss through the windows
7%
Basement floor
15%

Stack Effect

Air movement caused by warmer air rising and colder air falling. This generates small but steady pressures in direct relation to the size of the temperature difference and the height of the column of air. The resulting pressure differences can lead to air leakage and generate unplanned air flows that result in indoor air quality problems within houses.

These walls absorb water when it’s raining, as well as when it is snowing in the winter, causing cracks in the walls and build-ups of snow.

The resulting pressure differences can lead to air leakage and generate unplanned air flows that result in indoor air quality problems.

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