Deck Extension- Best Practices for Expanding your Deck

Deck Extension- Best Practices for Expanding your Deck


What are the most common reasons for deck expansions?  Perhaps you want to meet the needs of a growing family. Or maybe you plan on hosting bigger get together with friends and family. Keep in mind expansion can be as complicated as setting up a new deck altogether.

Following certain procedures and best practices eases the process.  One important point to keep in mind is that planning well in advance for a deck expansion is more than half the work.

Evaluate the structural integrity of existing deck

Thoroughly inspect the structural integrity and the substructure of the existing deck.   This means evaluating the posts, joists and beams. Look for splits in the wood, cracks and fissures.  Also, check for any sagging. First, confirm that the condition of your existing deck can withstand an expansion.  If the structure checks out, you can add extensions and new sections to make it bigger. Since so much rides on this decision, we advise calling a professional for a formal deck inspection.


Take statutory permissions

Your local planning department might have laws governing additions, replacement, and expansion of decks. If they do, you might be required to submit necessary plans for permitting. In that case, have a professional deck builder draw up the expansion plans. Professional companies use software programs to create 3 dimensional diagrams.

Sketch projected plans

First, make a sketch of your existing deck along with the beams, railings, stairways, joists and posts. This will be the basis of your deck expansion and will give you an idea of the new structure.  You will know where the weight of the extension will of beams, posts and joists in the first sketch. Include the outline of the extension and where it blends into the existing deck from the top view in the second sketch. Make a number of copies as you might want to tweak the specifications later on.


Installing your deck extension

While this is a job for building experts, here are some tips on how they do it.  There are variations to the process, depending on the plans drawn up and approved by you. Building the new sections starts with concrete supports. Posts are installed into the concrete foundation. Beams attach to the posts, creating the framework for the flooring. Joists provide perpendicular support between beams. Finally, place the joists into the hangars on the existing joints to strengthen the structure. These steps provide the platform for the extended deck flooring.  Once the framed platform is complete, deck boards are secured across beams and joists.  Railings are also installed on the perimeters.

For deck extensions, this is an outline of what the best practices should be in specific cases. The ultimate call depends on what you actually want to achieve.

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