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OST - 05.05.02 Accounting for Slope in an Area Condition (roofs, slanted ceilings, etc.)

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You can set up an Area Condition to accommodate a sloped plane such as a roof or an angled ceiling.

Set Slope on the General tab as Rise:Run.

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Area Slope Conversions

Use the charts below to convert Degree of slope or Percent (Grade) to Rise:Run.

Note

On-Screen Takeoff uses traditional mathematics to calculate slopes. This may not be the same calculation used for a specific industry.

Degree	Percent (%)	Ratio (Rise:Run)
0	n/a	0:1
1	1.75	1:57.29
2	3.49	1:28.636
3	5.24	1:19.081
4	6.99	1:14.301
4.7636	8.33	1:12
5	8.75	1:11.43
6	10.51	1:9.5144
7	12.28	1:8.1443
7.125	12.50	1:8
8	14.05	1:7.1154
9	15.84	1: 6.3138
9.4623	16.67	1:6
10	17.63	1: 5.6713
11	19.44	1: 5.1446
11.31	20.00	1:5
12	21.26	1: 4.7046
13	23.09	01:04.3
14	24.93	1: 4.0108
14.036	25.00	1:4
15	26.80	1: 3.7321
16	28.68	1: 3.4874
16.699	30.00	01:03.3
17	30.57	1: 3.2709
18	32.49	1: 3.0777
18.435	33.33	1:3
19	34.43	1: 2.9042
20	36.40	1: 2.7475
21	38.39	01:02.6
21.801	40.00	1:2.5
22	40.40	1: 2.4751
23	42.45	1: 2.3559
24	44.52	1: 2.246
24.228	45.00	1: 2.2222
25	46.63	1: 2.1445
26	48.77	1: 2.0503
26.565	50.00	1:2
27	50.95	1: 1.9626
28	53.17	1: 1.8807
29	55.43	1: 1.804
30	57.74	1: 1.7321
31	60.09	1: 1.6643
32	62.49	1: 1.6003
33	64.94	1: 1.5399
34	67.45	1: 1.4826
35	70.02	1: 1.4281
36	72.65	1: 1.3764
36.87	75.00	1: 1.3333
37	75.36	1: 1.327
38	78.13	1: 1.2799
39	80.98	1: 1.2349
40	83.91	1: 1.1918
41	86.93	1: 1.1504
42	90.04	1: 1.1106
43	93.25	1: 1.0724
44	96.57	1: 1.0355
45	100.00	1:1
90	n/a	1:0

This table shows the Degrees for each Pitch.

Pitch	Degrees
12	45
11	42.5
10	40
9	37
8	33.75
7	30.5
6	26.5
5	22.5
4	18.5
3	14
2	9.5
1	4

There are several Websites available to learn more about slope:

https://www.archtoolbox.com/representation/geometry/slope.html

http://www.secrets-of-shed-building.com/building-a-shed-roof.html

Caution

These sites are not published, maintained, or endorsed by On Center Software or any affiliate company, and these links are provided only as a convenience. All information contained on these sites should be independently verified for accuracy. On Center Software does not warrant the information or content.

Using the Rounding Option for Area Conditions

Creating Count Conditions