The building boom isn't slowing down. That's good for a raft of companies-including those that build telecom and data center infrastructure, such as Dycom Industries.

Wednesday, Dycom reported second-quarter earnings before intrest, taxes, depreciation, and amortization, or Ebitda, of $315.5 from sales of $2 billion. Wall Street was looking for Ebitda of about $297 million from sales of $2 billion.

Sales grew 46% year over year. Ebitda grew 53%. Dycom's backlog ended the quarter at $12.2 billion, up 53% year over year.

Shares were up 2.7% in premarket trading at 361.20, shortly after results were released, while S&P 500 and Dow Jones Industrial Average futures off 0.1% and flat, respectively.

"Demand across our portfolio is stronger than ever, fueled by a generational deployment of digital infrastructure that is projected to go well into the next decade," said CEO Dan Peyovich in a news release.

"We secured significant new awards, growing our backlog to a record level. We also officially welcomed National Technology Integrators to the Dycom family, further enhancing our leadership in digital and critical infrastructure and diversifying our business," he added.

National Technology Integrators builds digital infrastructure for commercial businesses, including data centers. Dycom entered into an agreement to buy the company for $275 million in May.

For the full year, Dycom expects sale of about $7.6 billion, up from prior guidance of about $7.5 billion. The new number is in line with Wall Street estimates.

It looks like another strong quarter. Shares jumped 26% after the company reported better-than-expected first-quarter numbers. Shares were north of $535 shortly after that quarterly report. They have given back gains and were just above $350 heading into the second quarter report.

Coming into Wednesday trading, Dycom stock was up about 4% year to date and and up about 37% over the past 12 months.