As with most lawyers, construction attorneys typically provide an initial session, often called a consultation, for free. If you are booking a first meeting, always ask if this is billed session or if it is free, as well as be prepared to leave a retainer if you are planning to hire the attorney.
Construction law is an extremely specialized legal field, so it helps to have an extremely specialized legal team on your side. The best construction law attorneys practice preventative law, rather than simply responding as problems occur; when you're looking, keep out for an attorney or firm with a proven record of doing this.