it sounds like you are in a great position for the BRRRR strategy. Buy, Rehab, Rent, Refinance, Repeat. being in the construction business you'll be able to identify properties where you can force appreciation buy fixing them up, once you have completed the rehab and are renting the units you can do a cash-out refi for 75% of the appraised value of the new and improved property, which allows you to pull out your initial investment to use as a down payment for the next property.
example: you purchase a 4 unit property for $100,000 with a 25% down payment. it requires $15,000 of repairs in materials, you can do the labor yourself. closing costs are $3,000. total cash needed up front: $43,000. after the renovation it appraises for $175,000. you do a cash out refi with 75% loan to value ratio for a loan amount of $131,250. closing costs for the new loan are $3,000 you pay off the old mortgage of $75,000 and you are left with $53,250 in your pocket to use on another deal, which is your initial up front investment of $43,000 plus an additional $10,250 that you get from the appreciation you forced with your renovation, so in total you ended up spending none of your own money, made $10k and now have a 4 unit property that probably cash flows around $1,000 a month. and you have $53,250 to do it all over again.