Extending Your Current Deck
Before you decide to add onto an existing deck, you should talk to your local building department. This may not be allowed in your area for a number of reasons. You may want to bring a few pictures of the existing deck along to help explain your situation. The inspector will usually want to review the permit and inspection records for the existing deck and may call for an as-built framing inspection to verify the condition of the deck before issuing a permit.
Most decks are not built with a future addition or extension in mind. Because of this, your frost footings are probably not large enough to support the new loads created by the addition. We recommend framing the new deck addition independently of the existing frame. In order to do this, you will need to install new beams and footings to support the addition.
Some deck builders choose to sister the new joists back over the existing beam and install a new beam in front of the existing deck. The sistered joists are nailed into the sides of the existing joists and extend past the beam at least 6". Hurricane ties are used to create a positive joist-to-beam connection. It may be necessary to install new posts and footings below the existing deck beam to support the additional loads. Most people that add onto their decks also replace the decking and railings on the existing deck at the same time. This will create a more seamless addition without noticeable color and weathering differences in materials.
How to Decorate Deck Support Columns
Browse some examples of decorative deck support posts for tall decks.
Deck Bracing
Learn how to install knee bracing in-between your deck support posts to provide extra strength against high winds and to prevent racking forces for tall decks.
How to Create Strong Post-to-Beam Connections
Learn how to create a positive structural connection for your post to beam connections. Use lag bolts, through bolts with washers, support cleats and hardware connectors.
Decking Patterns
Installing your decking at a 45-degree angle is a popular style for decks. This can be done to reduce decking seams or just for appearance.
10 Common Deck Building Mistakes & How to Avoid Them
Building a deck can be a complicated process. Learn how to avoid falling into common deck building pitfalls with tips and advice from the experts at Decks.com.
Picture Frame Decking
Install a picture frame or perimeter board to finish the edge of your deck with style.
More Helpful Resources
Explore Articles by Topic

Footings
Information related to installing frost footings for decks

Framing
Learn structural framing methods

Decking
Learn about wood and composite decking materials

Stairs
An in-depth look at the complex issue of how to build stairs

Railings
How to install guardrails and handrails to meet IRC code

Features
An overview on water drainage, benches, planters and lights

Design
The basics of deck design

Planning
Learn about permits and working with contractors

Porches & Patios
Build a covered deck to enjoy all seasons

Ledger
Proper attachment techniques

Care
Maintain your deck to maintain your investment

Materials
An overview on water drainage, benches, planters and lights
Extending Your Current Deck
Before you decide to add onto an existing deck, you should talk to your local building department. This may not be allowed in your area for a number of reasons. You may want to bring a few pictures of the existing deck along to help explain your situation. The inspector will usually want to review the permit and inspection records for the existing deck and may call for an as-built framing inspection to verify the condition of the deck before issuing a permit.
Most decks are not built with a future addition or extension in mind. Because of this, your frost footings are probably not large enough to support the new loads created by the addition. We recommend framing the new deck addition independently of the existing frame. In order to do this, you will need to install new beams and footings to support the addition.
Some deck builders choose to sister the new joists back over the existing beam and install a new beam in front of the existing deck. The sistered joists are nailed into the sides of the existing joists and extend past the beam at least 6". Hurricane ties are used to create a positive joist-to-beam connection. It may be necessary to install new posts and footings below the existing deck beam to support the additional loads. Most people that add onto their decks also replace the decking and railings on the existing deck at the same time. This will create a more seamless addition without noticeable color and weathering differences in materials.
How to Decorate Deck Support Columns
Browse some examples of decorative deck support posts for tall decks.
Deck Joist Cantilever & Overhang Rules
Learn what factors determine the maximum joist cantilever overhang that is allowed.
How to Angle Corners and Joists
Learn how to frame a deck with angled or clipped 45-degree corners using a cantilever beam.
Decking Patterns
Installing your decking at a 45-degree angle is a popular style for decks. This can be done to reduce decking seams or just for appearance.
Decking Patterns
Installing your decking at a 45-degree angle is a popular style for decks. This can be done to reduce decking seams or just for appearance.
Tile decking
Installing tile over a standard deck frame in an exterior environment is a recipe for trouble.
Explore Articles by Topic

Footings
Information related to installing frost footings for decks

Framing
Learn structural framing methods

Decking
Learn about wood and composite decking materials

Stairs
An in-depth look at the complex issue of how to build stairs

Railings
How to install guardrails and handrails to meet IRC code

Features
An overview on water drainage, benches, planters and lights

Design
The basics of deck design

Planning
Learn about permits and working with contractors

Porches & Patios
Build a covered deck to enjoy all seasons

Ledger
Proper attachment techniques

Care
Maintain your deck to maintain your investment

Materials
An overview on water drainage, benches, planters and lights