This is a front view of the before and a photoshopped representation of what the deck will look like after the addition project is completed.

One project we are currently working on at my dad’s house is wrapping his deck around the west side of his house.  It will then go almost 3/4 of the way around.  This post will be the first in a series to show how to add-on to an existing deck.

We are doing an add-on to my dad’s existing deck in the same style the original deck was built, and also adding a larger portion at the end with an eventual gazebo to house a hot tub.

The original deck is eight foot deep from the house out, and wraps all of the south side, and most of the east side of the house. It is build with 6×6 support posts and 2×8 cross members on those 6×6’s.  On top of those are 2×8 floor joists which are attached directly to the house at 24″ on center.  The decking itself is 2×6 boards.

There are several details that we will be mimicking.

How to add-on to an existing deck: Pay attention to the details

The most noticeable detail is the railing.  The vertical part of the railings are 1×6’s with two rounded cut-outs on each side, and the bottom cut to a point.  We will be duplicating this feature on the new deck.

Another detail we are duplicating is the base supports, done with 6×6’s and 2×8’s that are doubled, one on each side of the posts.  There is a 2×6 on the near side of the house, and the far side.  The support is one foot in from the outside of the deck, and so it is 7′ from the house.

The third detail we are duplicating is the 90º angle at the corner of the deck.  The floor boards meet at an angle, so the boards are all parallel to the house.

How to add-on to an existing deck: Improve the original design where you can

I estimate that this deck is about 30 years old.  We are making a few improvements to the design on the addition.  We are using Coated Deck Screws instead of the nails that always seem to be coming out, and needing pounded back in.  We are also re-coating the deck with a lifetime guaranteed coating which will be interesting.

Look for my next post about deck supports and planning.

Also Related: DIY deck & entryway design

Questions? Comment below, or tweet @HandyFather.