Frame Ceilings and Roofs

Any ceiling below an unheated space should be insulated with materials having a rating of R-19 or better. The ceilings should have

Table 3-6 Slab Edge Heat Loss

Outdoor Design Temperature,

°F

Total Width of Insulation, in Rated R-5

Heat Loss per Foot of Exposed Slab Edge Watts Btu/h

— 30 and colder

24

10.0

34

-25 to —29

24

9.4

32

—20 to —24

24

8.8

30

— 15 to — 19

24

8.2

28

4

1

To

9

1

24

7.9

27

-15 to -9

24

7.3

25

0 to — 4

24

7.0

24

+ 5 to + 1

24

6.4

22

+ 10 to +6

18

6.2

21

+ 15 to + 11

12

6.2

21

+ 20 to + 16

Edge only

6.2

21

+ 21 and warmer

None

Courtesy Electric Energy Association

Frame Ceilings and Roofs

Figure 3-24 Ceiling and roof frame construction.

A maximum U-value of 0.05. Some methods for providing such insulation are the following:

1. Staple blankets or batts to the joists before the finished ceiling is applied (Figure 3-24).

2. Blow or manually apply loose insulation between ceiling joists from above.

3. Spray on insulation between the joists from above.

Posted in Audel HVAC Fundamentals Volume 1 Heating Systems, Furnaces, and Boilers