(Aug. 16 update: The Remodeling 550 now has been released. Click here for highlights.)

Actual Results for 2015 and forecasts for 2016 for the 2016 Remodeling 550's full-service and replacement contractor groups

The nation's biggest remodeling, home improvement, and insurance restoration firms did a combined $4.22 billion worth of remodeling work in 2015, results from the soon-to-be-released Remodeling 550 show.

REMODELING's annual list of the largest firms also reveals distinctly different views about 2016 sales. The 150 replacement contractors on our list predict they'll rack up 27.2% more revenue from remodeling work this year, totaling $3.03 billion compared with 2015's $2.38 billion.

In contrast, the 445 full-service firms predicted only 4.9% revenue growth, to $1.54 billion from $1.47 billion. For the 100 biggest companies, the forecast was for just 1.3% growth. Design/build firms predicted the least revenue growth this year, forecasting just a 2.5% increase. Meanwhile, the general contractors said their sales for 2016 should show a 7.6% improvement from 2015. K+B businesses were a comparative rocket, predicting an 18.7% gain.

For the 17 insurance restoration firms, the growth this year was pegged at just 2.5%, to $380.9 million from $371.5 million.

The Remodeling 550 lists for each of those groups, plus the biggest franchise firms, will be released around mid-August.

The relatively low gains predicted by full-service remodelers comes despite a tradition in that group to be overly optimistic about future sales. For instance, the top 100 full-service remodelers on this year's list who also took part in last year’s survey had forecast in 2014 that their remodeling revenue would rise 12.4% in 2015. But this year, when we asked those companies to report their actual performance in 2015, the numbers they provided indicated only an 8.8% gain.

Replacement contractors did better. The top 50 firms taking part both years had predicted a 7.8% rise in revenue in 2015 from 2014. Their actual gain was 7.3%.

Collectively, those businesses did just under 530,000 jobs—438,120 in the replacement contractor sector, 60,874 by full-service firms, and 30,177 by insurance restoration companies.

This remains a top-heavy business: Among the full-service firms, the top 10 companies account for 22% of the entire group’s revenue. The top 100 garner 69% of the total. Replacement contractors are even more concentrated, with the 10 biggest firms on the 150-member list claiming 49.1% of all revenue and the top 50 firms accounting for 82.6% of all sales.

The full-service group generally breaks three ways: 52% are general contractors who do an average of 247 jobs a year, at an average job size of $109,941. Design/build firms account for another 38% of the total and do an average of just 104 jobs per year, but their average job size was $199,482. And all but two of the rest were kitchen and bath specialists, who averaged 180 projects annually with an average job size of $26,613.