My First Deck- ConHart Redwood

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Project by elschaefer posted 10-29-2012 09:08 PM 19602 views 1 time favorited 14 comments Add to Favorites Watch

This is my first deck project, and I’m pretty pleased with how it came out. It’s 12’ x 12’ and cantilevers off the hillside. The challenge was that I couldn’t put any sort of anchors into the ground near the oak tree because I couldn’t disturb the roots and the topsoil. I ended up having two concrete footings poured for the two 6×6 posts, then set the unsupported end of the beams on top of a bed of gravel so that water draining down the hillside wouldn’t sit around the beams and cause them to rot. Unfinished in the photos is the trough between the end of the deck and the dirt around the tree. I’m going to fill it with more gravel, then finish off the top with some red rocks to match the deck that will fill the area around the tree as well as the space between the deck and the tree. I also haven’t put a finish on the deck yet as it was only completed a few weeks ago. Any suggestions of a good clear or translucent finish that would help bring out the natural beauty of the redwood would be greatly appreciated.

You may notice that I pinned the mitered corners on the top rail of the railings with dowels. I was concerned about the wood warping over the years and thought adding 1/2” birch dowels through the joint would help keep the joints closed and looking good. We’ll see if I’m right!

In the second photo is my younger brother who was helping me build the frame. The deck was for our mother, recently she’s gotten into potting succulents and needed a space to do her potting that was outdoors and in the shade but far enough away from the house that she wouldn’t make too much of a mess. Next up will be a table for her potting needs that will wrap around the tree.

Thoughts, criticism, etc. would be welcomed!

14 comments so far

View AJswoodshop's profile


1057 posts in 2480 days

#1 posted 10-29-2012 09:16 PM

COOL! Nice job on the deck! I’m sure it will last for years!

View Surfside's profile


3389 posts in 2377 days

#2 posted 10-29-2012 09:34 PM

Can I spend the rest of my afternoon there? Nice work and nice place .

-- "someone has to be wounded for others to be saved, someone has to sacrifice for others to feel happiness, someone has to die so others could live"

View Jim Jakosh's profile

Jim Jakosh

21743 posts in 3309 days

#3 posted 10-29-2012 09:47 PM

Nice cantilever design!!.................Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

View gfadvm's profile


14940 posts in 2894 days

#4 posted 10-30-2012 12:56 AM

Nice deck in a beautiful setting. The doweled miters are a nice touch.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View redsox9's profile


105 posts in 2490 days

#5 posted 10-30-2012 12:59 AM

It will be interesting to see what happens with the mitered joints on the rail. You obviously know that is usually not recommended given the exposure to the varying elements that the deck will endure. Nevertheless,a great looking deck. Looks good and sturdy! Your mother will love it, I’m sure. Thanks for sharing!

-- Jeff, North Andover, MA

View DrDirt's profile


4511 posts in 3946 days

#6 posted 10-30-2012 01:44 AM

I might be a little nervous about the cantileve with no anchor of the back of the deck.
If your mom puts a grill out at the end and a lot of people migrate over to wher the best view is… Nothing keeps the deck from tipping awayfrom the hillside.

-- “The two most important days in your life are the day you are born and the day you find out why.” Mark Twain

View s2h's profile


29 posts in 2290 days

#7 posted 10-30-2012 03:43 AM

I agree with DrDirt. The cantilever design can be pleasing visually, but can also be dangerous if not properly anchored. I expect that people will tend to gather towards the overhang portion of the deck to admire the view. This could lead to a nasty fall for quite a few people.
I would estimate 60 to 80 lb/ft^2 as a live load on the overhang, and calculate the moment about the cantilever to estimate the necessary anchor weight at the uphill location (and then double it). You could probably add it in without too much trouble and without pulling any boards.

Deck Looks great thought!
Good luck!

View elschaefer's profile


17 posts in 2752 days

#8 posted 10-30-2012 05:00 AM

Thanks for all the positive comments and for the criticisms as well!

Jeff (redsox9)- my hope is that the dowels I put through the joints will help keep the miters together, I’ll let you know what happens.

DrDirt and s2h-
If any of you (or anyone else with the knowledge) could help me calculate the proper counterweight I’d really appreciate it, I’m actually planning to build a table around the tree with my leftover redwood lumber (with supports bolted to the end of the deck) and use it to help counter any tendency to overbalance the deck off the hillside so if I need to add weight I can easily do so in the design of the table. I stopped taking mathematics after high school so I don’t remember much beyond basic trigonometry, and I’m totally lost on calculating the moment about the cantilever as you suggested.

Here’s the relevant info:
The support posts are roughly 3’ from the overhanging edge of the deck, and there is 9’ of deck between them and the end that’s sitting on the hillside. There is also a diagonal support bolted from the bottom of the support posts to roughly 3’ from the end of the beams that sit on the hillside, which locks the perpendicular relationship between post and beam (assuming the 1/2” hot dip galvanized bolts don’t fail). The posts are 6×6 and the beams are 2 2×8s screwed together with #9 2 1/2” screws. The posts are notched at the top for the beams and bolted together with 1/2” stainless steel bolts.

Now I don’t think it’s a matter of treating it as a simple lever, because the diagonal support means the pivot point is at the bottom of the posts, not the top. How would I go about calculating this? My instinct was that this design provided much greater resistance to potential tipping even with a lot of unbalanced weight, but I could definitely be wrong!

Thanks LJs!

View a1Jim's profile


117340 posts in 3781 days

#9 posted 10-30-2012 05:06 AM

A super looking deck. I build a lot of decks regarding s2h concerns about the cantilever ,looking at the photo it looks like you only about 2ft or less of cantilever around 3 sides of the perimeter that is not supported . If you have your vertical 6×6s support beams set deep enough and concreted in place and you have metal fasteners between your horizontal and vertical beams you should not have any problems with lift. Another protection against lift is that you have all of you joist anchored to your horizontal 6×6 with metal fasteners. I still would not put 200 people on the deck at on time but i doubt you will be doing that with a 12’x12 ‘deck .

This was written while you were posting the above post.

-- wood crafting & woodworking classes

View elschaefer's profile


17 posts in 2752 days

#10 posted 10-30-2012 05:19 AM

Here’s a side view diagram of the deck and hillside:

View a1Jim's profile


117340 posts in 3781 days

#11 posted 10-30-2012 05:31 AM

I thought you had 4 vertical post . One idea that might help is to put another pair of knee braces on the outside of your 6×6” connected to your upper rim joist. Make sure you sandwiched 2×8 has plenty of screws or nails that hold them together. Even the way you have it built it would take a lot of weight on the outside cantilever to make it tilt.

-- wood crafting & woodworking classes

View DrDirt's profile


4511 posts in 3946 days

#12 posted 10-30-2012 04:50 PM

Agree with Jim – Now that I see the actual overhang is only 3 feet to the railing, I am less concerned.

The first photo made it appear that the main support was closer to the center of the deck so it looked like 5 feet overhang, and 7 feet of main deck. I would think that when you tie it in with the tree as you plan, there is a much less likelihood of tipping.

It really is a beautiful deck.

-- “The two most important days in your life are the day you are born and the day you find out why.” Mark Twain

View BigAl98's profile


173 posts in 3243 days

#13 posted 11-04-2012 05:09 AM

Just remember trees have a tendency to grow….if you anchor to the tree…the deck might tilt after a while.

-- Al,New Jersey -To thine own self be true

View kkcoral's profile


1 post in 1291 days

#14 posted 06-05-2015 01:13 AM

I think you did an excellent job on this deck. I’m starting to build my deck on a hill the same as this with an over hang. Any drawings, design sheets or photos would be greatly appreciated. Thanks Ed

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