How To Attach A Flower Box To Brick?

Window boxes are an easy and cost-effective way to beautify your home’s exterior. Most of the boxes that you will find today are made of PVC, making them much easier to attach to your home’s exterior. But, there are still preferred attachment methods for exteriors with brick.

To hang your flower box correctly, you will need to be familiar with a drill bit and a hammer. Hammer drills, like the name implies, provide percussion to the drill bit so that it can cut through hard masonry. This project is not possible with a regular drill. You can mount a flower box on the brick wall using the right drill and masonry bits.

Here is a closer look at how to attach window planter boxes to brick exteriors.

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How To Attach A Flower Box To A Brick?

Installing Flower Box

Brick is an exterior material that is very common in modern homes and many older homes built in the 70s. The great thing about brick is you can attach things to it. But avoid the use of brackets or other methods and try to attach directly to the wall.

Installing a window box on brick or stone is slightly different from installing one on the siding. You don’t usually have to worry about finding the studs, which can sometimes make it a little easier.

 You will need a drill that has a hammer action, also known as a Hammer Drill. Hammer drills are drills that spin and pulse front to back to break down bricks. These special drill bits, called masonry drill bits, have a chisel tip at the end that helps to break up bricks.

The process is easier if you’re using brick than if you are using stone. Some bricks are fragile and cannot be drilled into. 

Also, there might be unevenness in the brick’s surface that causes some bricks to stick out further than others. A handyperson can help you determine if drilling into brick is safe. Let’s get started.

Method 1: Installing A Window Box On Brick Without Support Brackets Underneath

You will need the following tools:

  1.  Hammer drill
  2. 5/8″ masonry drill bits
  3. Ratchet wrench
  4. 3/8 lag bolts
  5. Anchors for 3/8″ Lag Shield
  6. 5/8″ woodworking paddle bit
  7. Use silicone and a caulking gun.

This technique should not be used if you are trying to install a window box made of wood or hollow plastic. This method only applies to composite PVC window boxes that can be drilled through the backboard.

A direct mount is safe and does not necessitate the use of an assist bracket underneath. Instead, these boxes are usually decorated with a fake bracket underneath, which is also known as a faux bracket.

To mount such a box, it must be built of a solid material that can be securely drilled into. Fiberglass and hollow plastics do not generally fall into this category, but solid PVCs do.

1- Measuring:

  1. Measure and spot the flower box’s center.
  2. Mark the center of the cement sill beneath the window.
  3. Place the flower box on the ground so that it is roughly parallel to the wind.

2- Selecting Screws:

Determine the number of lag screws required to mount the box. One lag screw for every 24″ length of the box is a good guideline to follow. In this example, a 6-foot-long box will be used.

We suggest using one lag screw on each end and two more at the 24″ and 48″ marks for a total of four lag screws.

Instead of installing the lag screws at the very end of the box, they are usually installed 3-5 inches from the end.

Begin by drawing a horizontal line midway from the top and halfway from the bottom of the box.

Drill a hole at 4″, 28″ from the left end and 4″, 28″ from the right end.

3- Drilling: 

Use a 5/8″ drill bit to drill a hole the size of a nickel in these four locations. Then, on the back/top section, mark the center of the box and the center of the window. Place the box below the window sill so that the centers line up.

Mark 4 circles onto brick with a pencil through each of the 5/8″ holes you drilled through the back of the box. Set the box aside and take out the hammer drill.

Drill a 3″ deep hole through the brick in each of the four marked spots with a 5/8″ masonry drill bit.

4- Placing The Anchor:

 Insert a 2″ long 5/8″ lag anchor into the hole and tap it in with a hammer until it is snug but not too rigid.

Check that the entrance where the lag screw enters is facing outward. You’ll have four anchor points once all four lag anchors are tapped into the holes in the brick.

5- Putting The Bolts:

  1. Hold the box up and thread the four lag bolts through the holes in the back of the box and into the lag shield anchors.
  2. With a ratchet wrench, fasten each one to 90 percent.
  3. Once all four are clamped, place a level on the box and tighten completely.

6- Leveling The Box:

 Because the hole in the back of the boxes is 5/8″, it will be slightly larger than the 3/8″ lag bolts that will pass through. This allows you to level the box with some wiggle room.

Once the box is completely leveled, use clear silicone to seal the edges and make it watertight. You have now completed the installation of the box.

Method 2: Using A Support Bracket To Install A Window Box On Brick Or Stone

Woody Window Boxes

Read The Steps Of Method1:

Many of the guidelines from Method 1 will be applied if you use a support bracket. I strongly advise reading Method 1 first, then moving on to Method 2. Let’s get started.

Cut The Blocking To Length With A Saw: 

Measure the spacing between the end brackets, and add an inch or two extra for safety. It will be extremely easy to align if it is concealed behind the window box.

Verify The Depth And Level Of The Build-Out With The Ledge: 

If your window ledge is wider than ours, you’ll need to rip a 24 to make the bottom support flush with the ledge (this is what we measured for in Step 1).

Measure The Bracket And Mark Your Location:

 First, determine the distance between the bracket’s top and the bottom screw hole. Take the same measurement down from where you want the top of the flower box to be on the house. This is where the center of your build-out will be attached to the outside.

Determine The Number Of Support Brackets Required:

 You will need to buy support brackets and obtain a load-bearing capacity for the weight from the manufacturer for this.

A support bracket is typically made of wood or a metal bracket bent 90 degrees. Three support brackets are typical for a 60″ long box weighing less than 100 pounds when filled with dirt.

First, Determine The Box’s Height:

 You’ll want to ensure that the top of the bracket is at least this length lower than the bottom of the window sill to allow for sufficient space. It is prevalent to add an extra inch of cushion to ensure clearance.

Marking The Window:

 Using a pencil, mark the center of the window sill as well as the center of the window box. Measure and mark the window sill approximately 24″ to the left and right of the center mark for a 60″ box. This is where your brackets should go.

Using A Hammer Drill And Anchor System:

 You should install it according to their instructions based on your bracket and who made it. However, because this is on brick, you will most likely be using a hammer drill and anchor system to secure the bracket to the brick.


Put a drill bit set to the size of the lag shields into your hammer drill. Stiffen the chuck solidly.

To regulate the depth, wrap a piece of masking tape around the drill bit to the depth of the lag shields plus about 1/8 inch, or tighten a bit collar in place.

Drill into each marked hole with the drill set to “hammer.” Keep the drill level so the bit doesn’t wander and create an overly large hole.

Make the first hole. Comply your 2×4 with the mark you made earlier. If you have a brick exterior, you’ll need to drill your holes with a hammer drill and a masonry bit. Drill just enough into the wood to score the brick.

After scoring the brick, remove the board and finish drilling your first hole to make things easier.

Drill the last few holes. Return to the opposite end of the structure, level it, and drill the ones left. To support the build-out, we drilled six holes and used masonry screws.

Close your eyes against the dust and blow out the mortar dust from each hole. You can also blow the dust out of the hole with a blast of compressed air or dust remover while inserting the plastic straw into the back of the hole.

Insert The Lag Shield Into The Gap:

  1. Thread each lag bolt through a washer and into the support bracket’s hole.
  2. Tighten with a socket wrench, gradually increasing the torque as the bracket comes into contact with the brick face.
  3. Pause and check the level box in the window.

Pause and verify the box level in the window. Tighten the lag bolts and alter the window box as needed.

Set Your Brackets:

 We wanted our Mayne self-watering window boxes to be six ′′ from the window on each side. Knowing this, we evaluated our brackets to account for it.

Most support brackets are attached to the brick or stone, and the box is simply placed on top and removed for the winter.

Screw the bottom leg of the L-bracket to the flower box with screws that will not punch the window box. Screw penetration is unimportant if you’re using a plastic liner in the flower box. Fill the flower box with a soilless planting mix, plants, and flowers.

Suspend the window box. You can mount the window box once all of the brackets are in position! It conveniently tilts onto the brackets and can be removed for planting as required.

In this case, it is recommended that the box be mounted at least 1 inch above the brackets “absent from home. When directly mounting it, you can use silicone around the box to make it watertight, but if you’re using a support bracket with the intention of taking the box off and on, leave it 1 inch apart.

“Moving the box away from the house will aid drainage and prevent water from becoming trapped behind the box.

Combine the soil. For the flower boxes, I mixed vermiculite and raised bed soil 50/50. The vermiculite aids in moisture and nutrient retention while also lightening the weight of the box to prevent warping.

Packing peanuts should be used. Fill the bottom 2-3′′ of the window box with packing peanuts before adding the soil. This will also assist in lightening the load. Make certain that your peanuts are NOT biodegradable. They will also aid in drainage and watering.

Pour in the soil. Add the soil mixture after the peanuts are in place.

Begin planting! Now comes the enjoyable part: start filling your window boxes with plants and flowers. When choosing plants, consider how much sunlight will be available at that location. Please place it in an area where it will be easy to water and deadhead and where drainage will not damage the items below.

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