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DIY Outdoor Table: What to do with Leftover Composite Decking?

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.

gray composite decking pile on top of deck being built with arrow pointing to gray composite decking outdoor table.

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.

*Disclosure: I only recommend products I would use myself and all opinions expressed here are our own. This post may contain affiliate links that at no additional cost to you, I may earn a small commission. Read our full privacy policy.

Reasons To Use Composite Decking Material

Why use composite decking for DIY outdoor projects?

  • 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.

gray composite deck being built

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.

Gray timbertech decking board

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!

Gray DIY Outdoor Table

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.

man holding tape measurer show height of bench, him sitting and outdoor table

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

Outdoor Table Tutorial

1. 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!

2. 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.

Mitered gray composite decking used to create DIY outdoor table

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.

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.

4. 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.

Composite Decking Table top planed out

5. 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.

Pressure treated wood used for the base of DIY outdoor table

6. Use the saw to cut the posts. We cut our posts to 29 1/2″ tall.

Using a saw to cut pressure treated wood for posts for DIY outdoor table

7. 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″.

Create the beginning frame out of pressure treated wood and place on top of composite decking

8. 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.

Long galvanize screw used to attach pressure treated wood post to outdoor wood table

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

Attaching wood frame to post to create a base for composite table top to go on.

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

Table Frame for DIY Outdoor Furniture before composite decking top goes on.

10. 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″.

Add an extra 2' x 4' to the inside edge of outdoor table frame

11. 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.

Add mitered composite decking top to pressure treated wood outdoor table base

12. Use construction adhesive to attach the inside pieces of composite decking.

Smaller gray composite decking placed inside mitered table top frame on pressure treated wood base

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

Blue painter's tape used to separate pressure treated wood outdoor table base and composite decking table top

14. Use a paintbrush and use an exterior stain in the color of your choice. 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.

So we just ended up going with an outdoor stain (one that you would even use on decking).

Dark brown exterior stain being applied to pressure treated outdoor table base

15. 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>>>Looking for more weekend DIY Projects? Check out our post on 50 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.

Gray DIY outdoor dining table and composite benches made with leftover composite decking.

How-To FAQs

Can you screw the table top on from the bottom?

Yes, for some reason my husband said he liked the industrial look of seeing the screws on the tabletop.

How has the table held up over time?

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.

How heavy are these tables?

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.

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.

DIY outdoor table made with gray composite decking top with metal chairs.

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.

Large gray and DIY composite decking table with brown exterior stained legs with outdoor dining chairs.

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!

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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.



Monday 18th of July 2022

Hi Joyce. Good luck with your outdoor table!


Friday 27th of May 2022

How much composite decking did you use for this project?


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!


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.


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?


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 :)


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.

Brian Bayer

Tuesday 27th of April 2021

So if I understand this correctly, the leg post was 29 1/2 inches tall. The composite decking is 1 inch which puts the total height of the table at 30 1/2 inches? That also gives the clearance for chairs under the table for sitting at around 26 inches After you take away the 3 1/2 inches for the 2 x 4 frame and the 1 inch thickness for the composite deck? Did you find any difficulty finding chairs that would allow people to sit at a 30 1/2 inch table? I’m a little nervous at going near 30 inches as most outdoor patio chairs would be too low. But I’m also looking to make the clearance from the floor to the bottom of the actual table top at around 26 inches.

Any advice would be appreciated

Brian Bayer

Wednesday 5th of May 2021

@Erin, hello and thank you for the reply! It looks like we are going for a 30 inch high table. I was a little nervous about the 4 1/2 inch barrier from the top of the table but your response about sitting on a 17 inch bench put that at rest. I appreciate the help. My theory is if a standard chair is too low I can always purchase a firm cushion to add height.

Also I looked at the chairs from Amazon you use. They look great for outdoors. 2 questions:

Have you had any rusting from outdoor use? If so I’ll probably need a clear coating spray.

How hot do they get in the summer sun?

Thanks for all the help.


Saturday 1st of May 2021

Hi Brian. So my first piece of advice would be to find the outdoor chairs you want to add to your set before building. This way you can ensure you are comfortable using your table with the chairs you like. You could easily knock a 1/2 inch off the posts to customize this and make it a little lower, especially if you have 18" height chairs. The average height of a table is 28-30" and the average chairs area are normally around 18" but it can vary.

I will add a picture to the end of the post to show you my husband sitting at the composite bench we made that is 17" ish high. He is very comfortable and has leg room. You will see you could make a bench or chair have an 18-19" height and it could still work well. So I guess it just depends on the chairs you want to use, or you could always make a composite decking bench to go with your outdoor patio table. Good luck with your outdoor table project and we would love to see your finished patio table!

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