Question

Concrete and masonry foundation walls shall extend above the finished grade at a minimum of ______ where masonry veneer is used and a minimum of _______ everywhere else.

1) 2 feet, 1 foot
2) 1 foot, 2 feet
3) 3 feet, 2 feet
4) d) 2 feet, 3 feet

Answer 1

The question involves calculating heat flow through a wall with different layers of materials, each contributing to the wall's overall thermal resistance. Without the studs, it's a simple addition of R-values and application of the heat flow formula. With studs, the calculation must account additionally for their R-value and the space they occupy.

Step-by-step explanation:

The question presented pertains to the rate of heat flow through a wall with multiple layers each having its own R-value. Firstly, to calculate the heat flow without the studs, you need to add the R-values of all the layers to find the total thermal resistance. The formula to find the rate of heat flow (P) is P = ∆T / R, where ∆T is the temperature difference in degrees Celsius and R is the total resistance in R-values. In this case, P = (22 - (-2)) / (0.56 + 2.6 + value for fiberglass batts).

For the second part of the question, which includes the wooden studs in the calculation, you have to consider that the studs have a different R-value than the insulation, and they take up some of the space in the wall. Given that the studs are on 16-inch centers and have a different R-value, you would need to calculate the percentage of the wall they occupy, then adjust the overall thermal resistance accordingly to find the new rate of heat flow.

When masonry veneer is used, the concrete and masonry foundation walls need to extend a minimum of 2 feet above the finished grade. This is to provide adequate support and stability for the masonry veneer.