Carl has been a home builder for over 30 years and a construction loan consultant to credit unions for 20 years. He is also the founder of two schools of homebuilding, a former newspaper housing columnist, and author of several books on building your own home whose aggregate sales are more than ½ million copies. His book, Be Your Own General Contractor, has been in print for 25 years.

In April 2008, in response to the mortgage crisis, he was quoted as saying "In terms of finding land you want at a good price, this is the best market that I have seen in my 30 years of home building," in Money Magazine.

The key element to Heldmann's written work, in both his books and his website is estimating costs in home construction. He breaks down the selling price or market value of a house as follows: 25% material, 25% labor, 25% land cost, 12.5% builder profit, & 12.5% builder overhead.