Remodelers know that getting referrals and repeat customers means getting the details right. Yet, when it comes to water management systems for openings such as vents and electrical, many remodelers simply tape around the opening and cover it with a makeshift treated piece of trim board.

But that slipshod method often creates a weak spot for moisture to enter the structure—and it’s not very pretty, either. Not only does this approach look bad, it’s also likely to cause water intrusion and the dreaded mold.

That’s because using trim board disregards all principles of proper water management. Even if remodelers take the time to add a piece of top flashing, it takes extra time and labor to construct, attach, caulk and paint it. Plus, all that extra work will likely only last three to five years before the paint starts to fade and the board is compromised.

A better, more aesthetically pleasing method is using specially designed mounting blocks that are installed similar to window headers. The blocks, often made of recycled material, employ the latest science to maximize moisture movement away from the envelope of the structure while offering an integrated appearance with the structure. They come in a variety of configurations with built in flanges, flashing and slope to protect the wall behind the cladding and extend the life of light scones, vents or other items attached to the blocks.

Remodelers using these mounting blocks find the value typically exceeds cost differentials. That’s because the simple design provides a virtually foolproof way for a single sub to install the blocks rather than requiring multiple subs like the old-school method.

Here’s a detailed look at some of the key features specially designed mounting blocks have to offer—and why savvy remodelers are using them:

  • Side dams at the top providing a ¼-inch gap required by most FC manufactures.
  • Raised center diverter forces water to the edges of the block extending the life of the attached product.
  • Angled top edge flows water to front and prevents ice buildup in cold climates.
  • Large easy to use mount header and pre punched holes for quick install.
  • Bottom drip cap provides shingle style best practice drainage.
  • Clean wood grain appearance.
  • Arrive primed for field painting or prefinished matching the siding color.

For more on specially designed mounting blocks go to