The Web Marketing Association has an annual WebAwards competition, with 96 industry categories. One is “construction” and there is another category for “architecture”. Although the judging is voluntary, the competition isn’t free (though the $250 US entry fee shouldn’t be too much of a barrier.
(It also is something of a business. There were 10 recognized finalists in the construction sector. Multiply this number by the number of industry sectors, and the $250 entry fee, and you can see there would be a meaningful revenue source for the group.)
The WMA reports that the best construction website for 2016 belongs to Contech Engineered Solutions. While the award entry documentation says that judges often provide comments, I couldn’t see much in the way of commentary explaining why this site was the best, though indeed it is a nicely designed and well-developed site.