No matter your trade, it should come as no surprise that email remains the most effective method of delivering your invitations to bid (ITBs). However, subcontractors can’t respond to proposals if they never receive them in the first place. And subcontractors can miss out on ITBs if they don’t set their inboxes correctly to accept those projects.

For GCs, how will you ever get the best, most qualified bids back if your ITBs end up trapped between a spam filter and a junk folder? When it comes to email, deliverability is key to making sure your proposal gets to your intended audience and attracts the right bidders. 

How big a problem is deliverability? Consider this fact: Out of the top 43 global industries, construction-related email ranks among the worst offenders. Here’s how construction email ranks:


  • Unsubscribe rate = 1st Place
  • Hard Bounce = 1st Place
  • Abuse Rate = 1st Place
  • Soft Bounce = 2nd Place
  • Open Rate = 19th Place
  • Click Rate = 34th Place


Deeper Dive into Spam

So, how do you make sure your ITB emails don’t get marked as spam by subcontractors? Let’s first take a closer look at how spam is defined and dealt with as a larger issue.

Spam is unsolicited junk email that is sent out in bulk mailings. Specifically, spam is the main reason why some general contractors avoid email and prefer to communicate through outdated channels like the trusty old fax machine. 

However, these other channels are not as effective when it comes to reaching subcontractors who operate mostly in the field and live and die by their mobile phone.


Tips and Tools to Avoid the Junk Folder

For starters, you should double-check if your ITB emails comply with the 7 CAN-Spam Requirements.

Now, for some good news. There are some easy tools and tips to ensure your ITBs get delivered and seen by the right subcontractors. By taking some of these tips to heart, you’ll improve the chance that your email invite won’t end up in your subcontractors’ junk folder.

Take Cues from Marketing: Think of it this way: your ITB is marketing your company and your ITB is an advertisement of your project. Marketing has this down to a science. If you have a marketing department, have them review your ITB templates and wording and listen to their guidance.


Have Your Subs Implement a Whitelist 

If you’re using a bid management software, there should be instructions on how to have your company whitelisted by your subs to avoid invites getting marked as spam. A Whitelist, also called Approved or Safe Sender List, adds your email address (sender-ID) to a legitimate list your sub has created and will ensure your ITB gets delivered to their inbox.

Check Your Email Bounce Rate: If a lot of your subcontractor emails bounce back, it means you’re not keeping their information up to date. This is an indicator of the quality of your subcontractor list. For example, a bidding software can help improve your email bounce rate by scrubbing your subcontractor database list to remove bad information.

Avoid Trigger Keywords: Certain keywords are known to be spam flags. Check out HubSpot’s email spam trigger words list to avoid using these words in your email subject lines. You’ll improve your chances of getting past spam filters.

Use a Valid From/Sender Email Address: Use your name or company name in the “sender” field so that the subcontractor recognizes the sender. Unrecognized senders quickly get deleted or sent to junk. Do not use ones, such as updates@, reminder@, noreply@.


Time to Retire the Fax Template

Most importantly, it is time to retire your outdated fax template. As noted earlier, you should not spam your subcontractors. When you exercise due diligence and send your ITBs to qualified or relevant parties only, you can expect a higher response rate, i.e. better bids.

In addition, by directly emailing ITBs, you are using the most popular way to notify vendors. You should also think of your ITB as a great way to market and advertise your project to your preferred vendor database. Remember, even if you have the greatest ITB of all time, it won’t get much response if it doesn’t convey the right message to the right people at the right time.


Keep in mind the following statistics:

  • The average office worker receives 121 emails daily
  • The best times to send email are 10 a.m. or between 8 p.m. and midnight
  • The best days to send email are Thursday and Sunday
  • Email click rates increase by 300 percent if a video is included
  • The email open rate Is 17 percent higher if it is personalized


Adopting these best practices—plus using the right bid management tools—can make a world of difference for both GCs and subcontractors. Don’t let critical ITBs, project details, and documents get lost or misplaced in a mismanaged or jammed inbox.