| Characteristics | % |
| Position | |
| Master builder | 12 |
| Experienced construction worker | 65 |
| Assistant | 23 |
| Years of experience in the job | |
| Less than 1 | 3 |
| Between 1 and 5 | 30 |
| Between 6 and 10 | 30 |
| More than 10 | 37 |
| Manner in which the trade was learned | |
| Training course | 0 |
| Alone | 17 |
| By imitation | 41 |
| With a master builder | 42 |
| Age | |
| Under 20 years old | 12 |
| Between 20 and 25 | 25 |
| Between 26 and 30 | 18 |
| Between 31 and 35 | 7 |
| Over 35 | 38 |