Many entrepreneurs are very eager to land some free money (i.e. grants) to get the business going. Unfortunately, getting a small business grant is very difficult, especially if the desired grant is for a for-profit business such as a construction company. Most grants are given to non-profit organizations for programs and services that benefit the community.
If you intend to build construction that fosters community development in low-income housing there might be an opportunity. The first place to check would be grants.gov which lists several different grants. If there is a grant that fits your company's profile it will likely be granted by the US Department of Housing & Urban Development (HUD). Keep in mind that your construction company will need to fulfill several requirements. A construction company that just needs start-up capital probably won't cut it.
If you have difficulty finding a grant that your business is eligible for as I expect, you should consider other funding options. The Small Business Association (SBA) offers loans to startup businesses. You can also try to attain a bank loan.
Good luck with the construction company and helping to rebuild America.