Home » How to Install a Mounting Block on Existing Vinyl Siding? (Step-by-Step Tutorial)

How to Install a Mounting Block on Existing Vinyl Siding? (Step-by-Step Tutorial)

Are you looking for a way to add exterior accessories such as lamps, doorbells, and water faucets without damaging your siding? A mounting block is the answer—it is solid, low-key, and available in styles and colors that match vinyl siding panels. It lends interest and can last for the life of your house. The best part is that you can set it up in a few minutes with a few basic tools.

The best way to install a mounting block on existing vinyl siding is to recess it into the siding so that it is flush with the rest of the wall. Does this sound complex? It is actually easier than it sounds. Read on—I will show you how to install a nifty mounting block without tearing out your vinyl siding.

Tools needed for installing mounting block on existing siding

  • Mounting block set
  • Oscillating cutting tool
  • Utility knife
  • Screw gun
  • Siding tool
  • Spirit level
  • Pencil
  • Tape measure

Step-by-Step Guide to Install a Mounting Block on Existing Vinyl Siding

Follow these simple steps to set up a mounting block on vinyl siding in no time.

Step 1: Outline the mounting block on the siding

Outline the mounting block on the siding

Although you do not need to remove your siding to complete this project, you will have to cut a portion of it to install the block.

To get started, separate the mounting block from the trim it comes with; you will install the trim later.

Next, you want to mark the spot where you will install the block. Place the block on the siding with the screw flanges facing you and the face against the wall. Then, use a pencil to trace an outline of the block’s face.

Pro tip: Use the tape measure to check that the dimensions of the outline are similar to the actual block before cutting the siding.

Step 2: Cut the siding

Cut the siding

Use the oscillating tool to cut the siding along the outline you had drawn earlier. An oscillating tool is quicker and will give you a cleaner cut, but a utility knife can get the job done too.

Whether you use an oscillating tool or utility knife, the goal is to be as accurate as possible while cutting the siding. The face of the mounting block should fit snugly in the cut hole.

Take your time as you can along the top, sides, and bottom of the outline. Once you are done, you will be left with a hole exposing the house wrap behind the siding.

Instead of driving nails through the vinyl and potentially ruining the siding, you fasten the mounting block onto the house wrap and underlying studs. But we will get to this later.

Once you cut the hole in the siding, place the block to check that the face fits before moving on to the next step.

Step 3: Slide the mounting block behind the siding

Slide the mounting block behind the siding

Instead of installing it on top of the siding, you want to install the mounting block flush with the rest of the wall for a nice, neat finish. You will therefore need to lift the side panel and slip the block underneath.

Locate the seam between the panel on which to cut a hole and the adjacent panel horizontally. Slide your fingers to break the seam and then, use the siding tool to lift and uninstall the bottom of the panel. This will give you room to slip in the mounting block.

Slide the mounting block underneath the panel and fit it squarely in the cut hole. The block’s face should face you as the screw flanges face the house wrap.

Ensure that the mounting block fits perfectly in the hole you have cut. Use a spirit level to check that the mounting block is square and level installed in the hole.

Step 4: Fasten the mounting block to the house wrap

Fasten the mounting block to the house wrap

Now that you have fit the mounting block in the hole in the siding, the next step is fastening it to the house wrap.

Driving screws through the respective holes on the mounting block flange can be tricky, as the screw holes are hidden behind the siding. But, a screw gun can simplify the job.

Lift the siding panel, wiggle the screw gun in the open space you’ve cut through the siding, and drive a screw through one of the screw holes.

Drive a screw into each of the remaining screw holes to attach the mounting block firmly to the house wrap. Check for levelness each time you drive in a screw so you can correct any errors as you go.

Pro tip: Use galvanized screws as they are less prone to rusting. Set an appropriate depth on the screw gun to avoid driving the screws too deep into the wall studs.

Step 5: Re-install the siding

Re-install the siding

Once you screw the mounting block behind the siding, you can lock the panel back into the j-channel.

Hook the siding tool to the bottom folding of the panel, then pull it down slightly over the j-channel of the panel underneath.

Run your hand across the panel, applying slight pressure to snap the panel firmly into the j-channel. Check out this video for a nice visual explanation on how to fix a vinyl sliding panel that has come loose.

The mounting block should be flush with the rest of the wall if you have installed it properly.

Step 6: Install the trim

Install the trim

Mounting blocks come with a removable trim that gives the block a finished look that complements the rest of the siding.

Remember, at the start of the article. I asked you to remove the trim and set it aside before working with the mounting block. Now is a good time to put that trim to good use. Mount the trim on the block, and flush against the wall to complete the look.

That’s it! You now have a solid, good-looking spot to hang exterior wall accessories without damaging or removing the vinyl siding panels. Check out these extra tips below to get the most from your project.

Extended Tips

  • Choose the right mounting block for the job; the mounting block you need for hanging a house number or wreath is different from what you need for an electrical outlet or water faucet. Blocks for electrical outlets come with a weather-safe box for added protection.
  • Consider the color of your vinyl siding when choosing a mounting block. Opt for one that closely matches the siding color for a low-key, professional-looking finish.
  • Be sure to check the recommended weight your mounting block can support before purchasing and installing it. Some blocks will support heavy items like mailboxes, while others are more suited to lighter accessories such as small light fixtures.
  • Although some vinyl siding materials are hardy and feel rigid enough, it is best to avoid driving nails or screws directly into the siding. Puncturing vinyl siding can weaken the panel’s structure and shorten its lifespan. This is why I recommend installing the mounting block behind the vinyl siding.

Be careful when cutting the hole in the siding. You want to cut to precise measurements and not extend cutting past the outline as this will permanently damage the siding. Unnecessary cuts on the siding can let in water, potentially exposing your walls to water damage over time.

Summary: How To Install A Mounting Block on Existing Vinyl Siding

Accessorize your vinyl-clad walls can be tricky, especially if drilling through the vinyl panels is not an option. If you have been looking for a solution around this, mounting blocks is the way to go.

As you can see, they are incredibly easy and inexpensive to install, even for someone with basic DIY skills. Now, you can hang your wall planters, light fixtures, and other trinkets without worrying about damaging the vinyl siding panel. Just be sure to purchase the correct mounting block for the job.

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