If a wood deck is so short on space that it’s essentially unusable or it has a steep slope that makes enjoying the backyard difficult, a deck extension may be the perfect solution. Extending a deck over this area is a great way to reclaim valuable outdoor space and create the outdoor oasis your client has always wanted.

Extend Deck - Know Your Limits image



Step One: Inspect Structural Integrity

Before starting any type of deck extension project, inspect the existing deck to make sure the structure itself is still in good shape. Check the footings, posts, hardware and supporting lumber to ensure everything’s structurally sound and suitable for a deck extension. Any questionable areas should be repaired and/or replaced. When building a deck, never cut corners, especially when it comes to safety.

Extend Deck - Inspect Structural Integrity image

Step Two: Material Selection

Softwood lumber is not only strong and durable, it’s also affordable. It’s also easy to work with when it comes to staining. Strength is especially important as a deck is an extremely heavy structure. Any hardware should be heavy-duty and galvanized, so it will hold up to outdoor use.

Extend Deck - Material Selection image

Step Three: Designing Your Extension

Once you have sketched out your plans or done a rendering, you’ll have a solid idea on how your deck will look against your client’s home and landscape. Also, don’t let any mature trees get in the way of the deck, just incorporate them into the design. With proper planning, it’s not hard to deck around a tree or section of shrubbery.

Extend Deck - Designing Your Extension image

Step Four: Prepare Existing Deck

The construction crew will prepare the existing deck in a variety of ways for the new extension. They may cut back existing shrubbery in the area and remove specific supports to create space for the structural transition into the new extension. This means deck boards, railings and stairs may also need to be removed or disassembled, then reassembled for later use on the finished extension.

Extend Deck - Prepare Existing Deck image

Step Five: A Solid Foundation

With the new deck design in place, plot out where the new footers and posts will be installed. Then all the footers will be dug down to the proper depth based on local building codes, the deck’s design, and weight load. A high-strength concrete will then be mixed and poured into the holes and left to cure per manufacturer guidelines. Your particular deck design may also require additional ledger boards be installed along the home’s sill plate. Again, it’s important this foundation work is done to code, as it’s crucial for your client’s deck’s safety and longevity.

Extend Deck - Solid Foundation image

Step Six: Utilizing Temporary Supports

Usually the next step would be to install galvanized post brackets into the footers and add posts, but it’s not the only way to approach a deck build. In an effort to be more efficient, some crews will set up temporary supports using 2x4s and begin the framing process (see next step) while the footers cure.

Extend Deck - Utilizing Temporary Supports image

Step Seven: Rim Joists Installation

For this project, using temporary 2×4 supports, the crew set the first rim joist in place. A long 2×8 was placed perpendicular to the existing deck band. It was snugged up under the existing decking and toe- nailed into place using 16-gauge nails.

Extend Deck - Rim Joists Installation image

Step Eight: Support Beams Installation

Then the crew installed several 2×8 support beams that ran parallel to the existing deck. They periodically checked to make sure everything was square and level. Depending on the size of your deck, you may need more than one support beam.

Extend Deck - Support Beams Installation image

Step Nine: Floor Joist Installation

With the all the support beams in place, the crew began toe-nailing the perpendicular joists every 16- inches on center, making sure each board was level as they worked. Once all the joists were in place, joist hangers were secured using a palm nailer.

Extend Deck - Floor Joist Installation image

Step Ten: Framing Around the Landscape

Keep in mind, if the deck’s design incorporates trees, the floor system will require extra support posts and additional bracing around any deck openings. You’ll also want to ensure there’s room for growth if the tree is NOT yet mature. NOTE: Upon completion of the deck, you may also want to add wire netting around the opening or some type of safety feature if your client has small children or pets.

Extend Deck - Framing Around the Landscape image

Step Eleven: Placing Permanent Posts

Once the footers have fully cured, pressure treated posts will be installed. For this project we installed galvanized brackets into the cured concrete using a large masonry bit and bolt. Then posts were measured, cut to size and notched to fit snuggly against support beams. The posts were then secured into the bracket with the appropriate hardware and bolted to the support beams (may vary depending on the type of bracket/hardware). With all posts in place, the temporary 2×4 supports were removed.

Extend Deck - Placing Permanent Posts image

Step Twelve: Remove Old Decking

If the old, existing decking has seen better days, the crew will pry up the decking. Doing this ensures that the decking across both structures will stain and age in a uniform manner. It may be necessary to add perpendicular joists depending on your old deck’s orientation. This way all the new decking will run in the same direction.

Extend Deck - Remove Old Decking image

Step Thirteen: Install New Decking

With your subfloor system complete and all the old decking removed, new decking can be installed. Deck boards will be staggered and installed using 2 1⁄2 inch deck screws loaded into a coil screw gun. This particular deck design incorporated a deck band around the perimeter. At the end of each run, the decking was cut to accommodate this design feature.

Extend Deck - Install New Decking image

Step Fourteen: Railings May Be Required

An elevated deck will require a 3-foot railing to keep everyone safe and the deck up to code. When you’re deciding on the railing design, consider your deck’s height and if you have small children or pets as you may want to incorporate more boards into the railing design so there aren’t large gaps.

Extend Deck - Railings May Be Required image

Step Fifteen: Staining for a Cohesive Look

Finally, in order to make the new extension blend seamlessly with the old, staining all the boards the same shade is key. Per the earlier mention, new decking across both structures will go a long way towards getting that “brand new deck” look without the steep price tag. Keep in mind you may need to sand the older deck bands and re-stain them to match your new look.

Extend Deck - Staining for a Cohesive Look image