Ready your envelope – Part 1 is an overview of the role of a tight building envelope.
We covered the first of the three basic laws of physics that relate to building tightness in Part 2.
Why it matters: The leakiness of your house is directly related to your ability to control the conditions inside.
- Tightening your house is often the first step to controlling your comfort and indoor air quality.
🏃♂️ Quick review
👉 Hot moves to cold
👉 Wet moves to dry
👉 High pressure moves to low pressure
🔬 Zoom in: Water and water vapor are moving — down and sideways and even up — toward dry materials.
- Water will find the path of least resistance and exploit weaknesses in your roof, siding, windows, etc.
- Water vapor can go THROUGH most building materials like brick, stone, stucco, concrete and wood
- Example: Humid air in a crawl space is moving toward dryer air in the house — even if you have insulation between the floor joists
✅ For your Smart Homeowner list
- Keep this in mind when you think about your comfort — most people will find 75 degrees and 50% relative humidity to be very comfortable.
- 70 degrees with 70% humidity is not.
- In a humid climate you tighten the house to keep humidity out and then add dehumidification to handle the rest.