Jeffrey Edwards
Analyst · Ken Zener with KeyBanc
Thanks, Jason, and good morning to everyone joining us on today's call. As usual, I will start the call with some highlights on the quarter and then turn the call over to Michael Miller, IBP's CFO, who will discuss our results and capital position in more detail before we take your questions.
2020 is shaping up to be a record year, reflecting the success of our business model, the positive fundamentals underway across many of our end markets and the dedication, hard work and resiliency of our employees. IBP's strong operating and financial performance is encouraging given the unprecedented economic and social effects that COVID-19 pandemic has caused throughout 2020. I'm also excited by the long-term opportunities within our residential and commercial markets as a result of our ongoing geographic end market and end product diversification strategies.
As an organization, we remain focused on supporting our employees, customers and suppliers across the country. While ensuring our business is well positioned to withstand the impacts of the COVID-19 crisis as well as other natural disasters and business disruptions that occur from time to time. Across our national footprint, our branches continue to follow federal, state and local requirements in response to COVID-19, and I am pleased to report all IBP branches remained open during the quarter. In addition, the 2 hurricanes that made landfall in our Gulf Coast markets during the third quarter did not have a noticeable impact on our sales and profitability.
Overall, our record third quarter financial results continue to highlight the strength of our business plan, the power of our financial model and our core operating values focused on supporting our employees and customers. I'll use my time today to review these items and why we believe IBP is extremely well positioned for the current market environment as well as the long-term opportunities we have to create sustained growth and value for our shareholders.
Revenues during the third quarter were up over 6% and year-to-date are up over 9%. And when I look back at our business over a long period, I'm encouraged that our 2020 third quarter revenue is higher than what our full year revenue was prior to our 2014 IPO. We believe this success is a direct result of our focus on strong U.S. housing markets, our sales of complementary building products and our greater presence and participation within the multifamily and large commercial construction end markets. IBP's current geographic footprint continues to provide us access to nearly 70% of total residential permits compared to approximately 50% 6 years ago.
During the quarter, single-family completions in the U.S. increased 2.6%. Analyzing market data and our results, we believe the lag between starts and completions has increased as a result of the COVID-19 pandemic due in part to labor and material shortages impacting other construction trades within the industry and a delay in homebuilding returning to full production following the COVID disruptions earlier this year. We believe these timing factors have impacted the comparability of our sales to the rate of completions in just one quarter.
Typically, we see our largest volume of insulation installation during the third and fourth quarters of the year. In the 2020 third quarter, we benefited from a higher mix of complementary product sales, which are typically installed later in the production cycle than insulation, further indicating a longer production cycle and the conversion of industry backlog to completions. While we anticipate a return to normalcy in the coming quarters, the increased lag between starts and completions and the dramatically increased order volumes from our builder customers will have a more meaningful impact on our business in 2021.
During the quarter, multi-family growth remained strong and helped drive a 1.6% increase in same-branch residential sales during the third quarter. Given the timing of completions and when we perform our install work, we believe it is useful to analyze our performance over multiple quarters.
Looking over the 9-month period ended September 30, 2020, residential same-branch sales have grown 4.4% compared to an increase in total completions of 2.2%. The higher mix of complementary building products, combined with a higher mix of multifamily sales, also impacted both price/mix and gross margin during the quarter compared to the 2020 second quarter. However, on a year-over-year basis, the benefits of our pricing strategies, combined with higher total sales volume, helped drive a 160 basis point increase in our adjusted gross profit margin.
Recently, a material price increase effective January 2021 was announced for our fiberglass insulation materials. This increase is in line with our expectations for an increase early in 2021. With our availability of labor and our strong position with our customers and suppliers, we believe we are all well positioned to navigate the deflationary environment next year.
We believe single-family industry dynamics remain strong and support the continued demand for our services. According to the U.S. Census Bureau, single-family starts in September were up over 20%, and single-family homes under construction increased to the highest level since December of 2007. We also believe we are well positioned for continued multifamily growth as a result of our suburban market focus and the success of our expanded multifamily sales strategy.
As you can see, our residential markets have quickly rebounded from the COVID-19 pandemic, and market trends remained favorable. As we highlighted in last quarter's call, COVID-related safety protocols on large commercial construction sites continue to affect our operations. This has slowed the timing of our work and disrupted schedules as we adhere to requirements of managing the number of trades on the job site each day. While we expect to see this continue into the foreseeable future, we are encouraged by the relative strength in the end market.
Our commercial backlog at September 30 was up 5% compared to the prior year, and our total pipeline and bid activity within the large commercial market has remained stable over the past 3 months. Based on the long lead time nature of our projects, we believe this will benefit our large commercial end markets in the second half of 2021. We believe our solid pipeline and growing presence within the large commercial end market will help us navigate any near-term softness.
Long-term fundamentals are expected to remain intact, and diversifying our end market exposure continues to be an important component of our growth strategy. In addition, we are opportunistically pursuing additional commercial acquisition opportunities that increase our scale competitiveness.
After briefly pausing our acquisition closings at the early stages of the COVID-19 crisis, our acquisition strategy has started to accelerate. In August, we acquired Storm Master Gutters, a New Jersey-based provider of gutter installation and repair services to residential and multifamily customers with annual revenue of approximately $20 million. We also acquired the North Charleston, South Carolina and Pooler, Georgia branches from Energy One America in August. These branches provide spray foam, fiberglass and air barrier installation services to residential, multifamily and commercial customers with combined annual revenue of approximately $22 million.
So far in the fourth quarter, we have made 2 additional acquisitions, both in the Pacific Northwest. They include a provider of insulation, waterproofing and fire-stopping installation services to commercial and multifamily customers with annual revenue of approximately $26 million and an installer of specialty coatings for fire protection, insulation and acoustics in commercial and industrial applications with annual revenue of approximately $10 million. To date, we have acquired 8 installers with approximately $94 million of revenue compared to 6 installers with approximately $36 million of revenue at this time last year. As you can see, 2020 is shaping up to be another strong year of acquisition growth. Our acquisition pipeline remains robust, and we continue to actively pursue acquisitions of well-run residential, multifamily and commercial installers that support our geographic product and end market diversification strategies.
Before I turn the call over to Michael, I want to highlight the record profits we are achieving. Record quarterly sales, strong gross margin and controlled operating expenses continued to produce record profits. Our same-branch incremental adjusted EBITDA margin was over 100% for the second consecutive quarter and helped drive an 18% increase in third quarter adjusted EBITDA. In addition, our trailing 12-month adjusted EBITDA margin has expanded to 14.5% from 12.6% for the same period last year, a result of lapping the impact of the material inflation environment in 2018 and our subsequent pricing strategy.
So to conclude my prepared remarks, I'm extremely pleased with how our team has responded to the unique challenges that have occurred throughout the year. Our continued success reflects the power of our business model, the experience of our management team, the long-standing customer relationships we have developed and the strength of our balance sheet and operating cash flow. We believe that we will achieve record results in 2020. And given current market trends, 2021 is expected to be another strong year for IBP.
As always, I'd like to thank our installers who are hard at work every day, representing IBP and serving our customers. On behalf of the entire leadership team, we recognize your efforts, and I want to personally thank you for your dedication.
With this overview, I'd like to turn the call over to Michael to provide more details on our third quarter results.