Should I quit my job?

[Robert Cornish]

I need some advice about my situation.

My name is Rob, I'm from the UK and I'm 18. I have very safe job as a cartographer (map drawer) that pays a very low salary. I still live with my mother so my monthly expenditure is very low and I am saving a fair amount of money. I know I could keep and work this job for a very long time. There are very few promotion opportunities within my company and judging by the cars in the car park, the money isn't there either. 

My Dad has worked as an independent builder all his life. He either buys one house, knocks it down and builds two or develops from scratch. He got burned in 2008 and the opportunities haven't been available for some years. He will be confirming purchase of a plot of land in two weeks and it will take him roughly 6 months to build the house on his own.

So should I, keep my low paying and very secure job with the knowledge that there will always be a full time job for me at the company or  should I ask if I can help my Dad build the house to find myself without a job in 6 months time?