How to Solve an Uneven Surface Deck Installation

a shovel in the dirt
  • 4-8 hours
  • Beginner
  • 50-100
What You'll Need
Wooden stakes
Plate compactor
Masonry sand
Metal fasteners

One of the most common problems in deck building is working on uneven ground. However, there are 2 relatively easy ways of solving this problem. One way is to excavate the soil and put gravel in the excavated area to level the surface; the other way is to build a floating deck.

Step 1 - Mark the Perimeter

Prepare a plan for your deck. Mark the perimeter by driving the wooden stakes on the ground with a distance of at least 1 foot between each stake. Connect the stakes by stringing them tightly.

Step 2 - Excavate the Soil

With the help of a shovel and a pick, dig the soil to a depth of about 5 inches. Level the excavated ground using a rake. Make the soil firmer with the help of a plate compactor. Drive extra stakes at the corner of the area to measure the depth of the excavated ground.

Hold back the edges of the perimeter by putting landscaping stakes into the soil. Put another 4 inches of gravel finely crushed over the dug-up area. Level the area again with the rake; this should fix the uneven surface ground, creating a more ideal base where the deck can be installed.

Step 3 - Work on the Deck

Cut pressure-treated planks to build the deck surface. Notch the initial deck plank around the deck post, cutting the notches with the jigsaw. Use galvanized deck screws to install the deck plank. Proceed to install the other planks as one would do in finishing a deck.

Another way of solving the uneven surface dilemma is to build a floating deck which is explained in the subsequent steps.

Step 4 - Building a Floating Deck

Through a post and beam assembly, you can build a floating deck. Install the posts by placing them in a hole filled with concrete or by fastening them to a metal bracket. The metal bracket must be fixed to the ground with solid concrete. The posts should be cut to get the ideal height.

Prepare the area where the deck will be installed using gravel. Lock up a couple of joists with dimensions of 2 by 6 inches to establish a support beam: one joist for each post. The beam support to the posts should not exceed 6 feet in between them.

Step 5 - Finishing the Deck

Secondary joists are then placed from the beams about 16 inches from the center with the use of metal joint hangers. Joists may also be attached across the upper part of the beams.

The problem with a floating deck is that it may be more difficult to build it compared to a simple deck installed over a flat surface; it will also take a longer time to finish a floating deck apart from using more materials such as concrete, gravel, posts, and metal fasteners.