Did you just build a composite deck? Learn how to build a large DIY outdoor patio dining table out of Trex decking. We absolutely love that this outdoor DIY project used some materials we already had.

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We recently put a brand new screened-in porch and deck onto our house. We are all about DIY projects, but this big deck and porch we left to professionals. They left us with a bunch of leftover composite decking that we just couldn’t waste.
We absolutely LOVE this outdoor space, but we needed ideas for what to build with our leftover composite decking. Here is our step-by-step DIY outdoor table tutorial.
Reasons To Use Composite Decking Material
- More rot resistant than wood
- Is more bug resistant
- Less maintenance
- No need to buy gallons and gallons of stains and sealers like wood decking
- Some companies use recycled materials to create composite decking
- Nails are not as visible (decking technology is always improving)
Why build a deck out of composite decking?
If you are building a deck that you want to last composite decking is the way to go. While the price is more expensive at the beginning you will have less maintenance (like our DIY composite deck cleaner) and it will last for at least 25 years or more as it says in this HGTV article.

Save Money By Using Leftover Cut Pieces
In the image above you can see the in-progress composite deck being built. We had a lot of leftover pieces of composite decking since you buy it by the board.
Why not use leftover composite decking pieces when building outdoor composite furniture?
Composite decking will not rot like even pressure-treated wood and bugs don’t seem to like the product. Not to mention you can get Trex or composite decking in a variety of colors without having to stain it.
What can you build out of leftover composite decking?
- Composite decking benches
- Flower boxes made out of Trex
- Outdoor bar made from Polywood or composite decking
- Outdoor side table
- Coffee Table
- Outdoor Adirondack chair
- Shelves
- Wall Art
- Step stool
- Cornhole game
- Birdhouse or birdfeeder
- Raised garden bed (you can see our cedar raised garden boxes here)
- Outdoor dining table
- Outdoor playset or platform for a playhouse
As you can see, there are many different project ideas that can be made with leftover composite decking.
To buy or not to buy an outdoor table?
If you shop around for different outdoor tables, they can be quite pricey. The idea that we could reuse a material we already had for an outdoor table was a way more budget-friendly and eco-friendly solution.
I just couldn’t bring myself to buy a new table when we could make one. The gray decking boards would be a great DIY outdoor tabletop.

Decking Table Design
One of these projects was to create a DIY outdoor table that would be able to sit with more than 10 people. We decided on making two smaller and skinnier composite decking outdoor tables instead of one large one.
Having two outdoor tables allowed flexibility in seating options and they would not be too heavy for moving around.
If you are looking for another DIY table, we also recently just made our own DIY folding tables out of plywood. This cheap folding table is to be used in our basement for my husband’s poker and game nights. If we end up needing to sit more people outside, we plan on using these as well!

How to determine the height of your outdoor table?
Tip: If you already have chairs, make sure that you are building the height of the table to accommodate those chairs (like ours) or any standard outdoor chair or stool. We also made composite decking benches that you can see at the end of the post.
Here you can see the end height of our table and my husband sitting at our DIY bench. This may help you see the leg clearance and if you need to adjust the original height of the table due to your seating choice.

What is the normal average height of a table?
An average table is normally anywhere from 28-30″ with chairs ranging in height in the 18″ range. Our bench is actually 17″ tall with a table that is 30 1/2″ which fits my husband well, but maybe I would have liked the table to be maybe a 1/2 inch shorter due to the fact that I am shorter.
Recommended Supplies
- Composite Decking: I absolutely love the color and boards we picked out for the deck and knew we had to use the leftover composite decking boards we had.
- Pressure-Treated 2″ x 4″ x 16′ (quantity needed 3)
- Pressure-Treated Posts 4″ x 4″ x 16′ (quantity needed 2)
- Construction Adhesive
- 3″ Screws (my husband really recommends these screws for outdoor projects and pressured-treated wood)
- Miter Saw
- Painter’s Tape
- Exterior Stain
Outdoor Table Tutorial
Step 1: Design Your Table
Figure out the dimensions you want to have for your outdoor dining table. Each outdoor table is 70 1/2 ” long x 32 1/4″ wide x 29 1/2″ tall.
Here is an article about how to help determine the right size table for your indoor or outdoor space.
We made two of these tables so that we could put them together and really fit our extended family!
Step 2: Miter Cut Outside Composite Decking Boards
Miter outside composite decking edges of the outdoor table. We decided to create a picture frame on the outside and fill it in with the other pieces.

You will have to do some math to decide the length of your table and how many full pieces of composite decking you will fit in the inside frame.
Step 3: Cut composite decking to fill the inside.
We cut our small pieces to 21 1/4″. It took 11 pieces to fill our “picture frame”. We put our inside table pieces going horizontal to use the smaller leftover pieces of composite decking.
Our Mistake: I wish we would have changed this design and made the inside slates to be vertical. It was very difficult to have all the composite decking lay flat and we have some spots that stick up a little. It is nothing a little placemat won’t be able to fix. But you can learn from our mistakes.
Step 4: Dry Fit Pieces Of Tabletop Together
Layout all pieces of your outdoor tabletop to see how it all fits together. For each table, we made 71 1/2″ long and 32″ wide. We wanted a longer and skinnier table for our space.

Step 5: Start To Build Base Out Of Pressure Treated Wood
Gather pressure-treated posts. We used sturdy posts because my husband liked the look of a thicker base. I am pretty sure this table could have been built with cheaper pressure-treated 2 x 4s.

Step 7: Build Frame For Composite To Rest On
Build the frame that supports your DIY outdoor tabletop. We used pressure-treated 2 x 4s to create a rectangular base at the size of 27″ x 66 3/4″.

Step 8: Attach Frame To Table Legs
Drill pilot holes and 3″ screws to attach the frame together and then attach posts. Make sure you do not use just any steel 3″ screws because the metal will corrode over time.

Tip: Use clamps to secure the post to the table frame. (See picture below)

Step 9: Flip Table Frame Over
This is a simple step: Flip the frame over (don’t mind our trash can overflowing).

Step 10: Add Extra Wood Supports
Add 2x4s inside the table frame so that the composite tabletop can be attached there. Our 2x4s were 7″ less than the frame. Ours were cut to 20 1/2″ x 59 3/4″.

Step 11: Attach Composite Deck Boards To Frame
Use the drill and screws to attach the composite decking picture frame to the pressure-treated wood frame. You could also attach from the bottom if you do not want to see the screws.

Step 12: Attach Horizontal Boards
Use construction adhesive to attach the inside pieces of composite decking.

Step 13: Prep For Exterior Stain
Flip the outdoor patio table over and use painter’s tape to frame out the composite decking tabletop and pressure-treated wood.

Step 14: Stain Wood Legs & Frame
Use a paintbrush and use an exterior stain in the color of your choice.
We just ended up going with an outdoor stain (one that you would even use on decking).

Step 15: Let Table Dry
Let the DIY outdoor table dry and then flip it over and set it up in your outdoor space. We also made DIY outdoor benches using the same steps listed above but on a smaller scale.
Related Reading>>>Check out 50 More Weekend Home DIY Projects
Composite Decking Outdoor Benches
You can also make composite deck benches that follow a similar design plan. Use 3 pieces of composite decking on top. Create a base out of matching pressure-treated lumber.
Our benches are 48″ long and 16 1/2″ tall.

How-To FAQs
Yes, for some reason my husband said he liked the industrial look of seeing the screws on the tabletop.
Composite decking becomes flexible. We have had a few boards that we have had to reglue with construction adhesive. However, since they rest on the wood frame this isn’t that big of a problem.
They are pretty heavy due to the posts being used. You probably could use 2x4s for the legs instead of the posts. For the size of our table, it takes two people to lift and move around.
I did a lot of research to see if I could use interior stain because I LOVE the look of this color (we have used it on numerous projects in our house).
However, you would need to do another coat of special polyurethane. We decided we only wanted to paint the exterior stain on the outdoor table post once and that we wanted as much protection as possible with the least amount of maintenance.
Our Related Outdoor Posts
Finished DIY Outdoor Dining Idea
Our two DIY outdoor dining tables were so awesome to use the other night! We were able to sit with our whole immediate family and friends. The kids loved the benches and being able to eat outdoors.

What is your favorite outdoor dining space project? If you like this project, you may also like seeing some of the amazing painted flower pots we made to plant things that would help repel mosquitos while we dine.

Follow us on Pinterest, Youtube or Facebook for more DIY inspiration!
We absolutely love our DIY outdoor dining space and hope we inspired you in your next DIY project!

DIY Outdoor Composite Decking Table
Equipment
- Miter saw
- Cordless Drill
Recommended Supplies
- 3 2" x 4" x 16' Pressure Treated Boards
- 2 4" x 4" x 16' Pressure Treated Posts
- 3" Deck Screws
- Painter's Tape
- Exterior Stain
- Paint Brush
- Leftover Composite Decking
- Construction Adhesive
Instructions
- Design table. Each outdoor table is 70 1/2 ” long x 32 1/4″ wide x 29 1/2″ tall.
- Miter outside composite decking edges of the outdoor table to create a picture frame look.
- Cut your small pieces of composite decking to 21 1/4″. It took 11 pieces to fill our “picture frame”. We put our inside table pieces going horizontal to use the smaller leftover pieces of composite decking.
- Dry fit table together.
- Start to build base. Cut pressure treated posts to 29 1/2".
- Build frame out of 2 x 4s.
- Attach frame to the legs using 3" deck screws.
- Flip table frame over.
- Add extra 2 x 4 supports inside frame.
- Attach the ouside composite decking boards to the frame. You can screw in the top of from the bottom.
- Attach horizontal decking boards with construction adhesive.
- Flip over and prep for exterior stain.
- Use a brush to apply exterior stain to pressure-treated wood.
- Let dry and enjoy your new outdoor table.
Erin
Sunday 2nd of April 2023
This is a great tutorial! Thanks for sharing your beautiful project and for such thorough instructions.
Erin
Monday 3rd of April 2023
Hi Erin. Thanks for the kind words and good luck with your outdoor table.
Joyce
Sunday 17th of July 2022
Awesome idea, I used my left over deck board on top of an old picnic table. Now I will build the frame as you did.
Thanks
Erin
Monday 18th of July 2022
Hi Joyce. Good luck with your outdoor table!
Sarah
Friday 27th of May 2022
How much composite decking did you use for this project?
Erin
Monday 30th of May 2022
Hi Sarah. We used the leftover pieces from when our deck was being built and did not buy new pieces for this table. If you are buying new composite decking for your outdoor table, I would make sure you get the boards meant for the edge of a deck for the edge of your table. Our table has a little groove there because we didn't buy new. Good luck with your DIY table.
Kevin Crimi
Monday 27th of September 2021
I've been trying to find pressure treated wood but everywhere I go, the only option is the really ugly brown stuff with incisions along the length. Is there something specific I should be looking for/asking for to find some normal looking boards like you have? Thanks!
Erin
Tuesday 28th of September 2021
For our table, we used #2 grade pressure-treated wood. We always recommend trying your local lumber yard and they will let you pick out your individual boards. Good luck with your outdoor table.
David
Monday 30th of August 2021
Hi Erin, Thinking of doing the same - would you say that table is super heavy or easy for 2 ppl to move around?
David
Tuesday 31st of August 2021
@Erin, Thank you - think I might put the frame together in the shed and then build the rest already on the deck to avoid the hassle of 7 stairs :)
Erin
Monday 30th of August 2021
Hi David. My husband and I can move the table around, however, it wasn't easy to get up onto our deck. The weight is mainly due to the chunky legs, so you could always change the frame to make it a little lighter. Good luck with your DIY outdoor table.