10 Amazing Trex Deck Installation Tips

Inspiring and encouraging you to DIY a Trex deck yourself using my amazing Trex deck installation tips! I did the hard work to come back and sharing the good, the bad, and the ugly and all of the tips I learned along the way to help you do your next deck project. This is how I built a Trex deck.  A DIYer sharing her best tips!

What brought me to this? Showing you how I built a deck with my own two hands?

If you missed my post about my parent’s deck, set in the woods, off of Puget Sound in Seattle, then you probably have no idea why. However, if you have been here a while you do probably know that I don’t have a deck or any need for one.

But, my parents do!  And my heart just wanted them to have a nice place to spend their evenings by the fire.

Have I ever built a deck before? Nope.

So here I am.  And I am going to tell you upfront that YOU CAN DO HARD THINGS, friend.

Wait until you read what happened that made me ugly cry! Sometimes DIY can be really, really hard.

How long does it take to order Trex?

I began this journey by having my parents take measurements and send me photos. The deck is 12′ x 14′.  I went to my local Lowe’s and saw all of the color options for Trex decking planks and design options for the railings.

I went home, figured out how much I needed to order based on the measurements of the deck and ordered the Trex decking, railings, and all the necessary hardware and fasteners from Lowe’s. It would take 5 weeks before my order would arrive so we scheduled my arrival around the delivery date that Lowe’s gave me and I would be there for 10 days.

Order your supplies well in advance of your project and pay for delivery. Your delivery will come on a large flatbed truck and also be palletized. We delivered from Lowe’s for $80 extra and it was SO worth it.

There is no way that I could have gotten everything we needed into the van or in one trip. Lowe’s delivered right to the driveway so all I had to do was tell them where to put it all and get to work. The planks are so heavy and I had ordered them 16′ long.

How much does a new Trex Deck cost?

For a 12′ x 14′ deck, the cost was under $4500! This is where the beauty of DIY comes in to play. Most of the cost is in the labor. My parents were quoted a crazy amount for a new deck! I have a great before post if you want to see where this all began and how much they were quoted.

The cost breakdown for a Trex Deck is in my final reveal post!

If they lived close by then I would have been able to just use all of my tools, but they don’t so they had to invest in a few items they didn’t have. They had to purchase a miter saw (that they will probably never use again, but we really needed it!), a drill, and a multi-tool costing them an extra $378 for this project. I did have to improvise a little with the available tools and bits they had, but it all worked out.

I needed a new jigsaw anyway so bought one to use while I was there as well and then I brought it home.

Side note: I found out the hard way that “no power tools are allowed in your carry-on, M’am”.  Not even a plug-in jig saw with no blade, LOL!! Not sure what they think I will do with it, but I had to check my bag anyway.

What is the difference between Trex and wood?

Want to see why I chose to build a Trex vs. wood deck?

I shared all the reasons that Trex is better in a recent post. Especially in the Pacific NW where they experience all the rainy weather you could ever imagine.

In a nutshell, it lasts longer. Doesn’t rot. Doesn’t need to be refinished every year.

Luckily the one week I was there the weather was absolutely beautiful. So beautiful that I considered never leaving. But then it rained on the day I was going home and I was quickly reminded of why I don’t live there, lol!

What tools do I need to install a Trex Deck?

• Miter Saw
• Tape measure
• Speed square
• Power Drill
• Various drill bits including a socket bit to fit the appropriate bolt size for railings
• Gloves
• Kneepads
• Rubber Mallet
• CORW BAR?
• Multi-tool (optional)

How do you prep for a Trex Deck?

I didn’t want to spend my limited time there tearing the old deck apart so they hired a handyman to disassemble the old decking and haul it all away. The underpinning or structure was in great shape so that saved me from having to start from scratch. I spent the first couple of days bracing the deck for the railing posts that I would be installing. If your structure is not sound, then you will need to replace all of the support pieces (or joists) first.

Now all that needed to be done was to build the deck on top of the structure with the braces I had installed.

“All that needed to be done”. Famous last words. You may not be able to tell at this point, but this project was about to make me feel and look OLD!

While I was busy doing prep work, my daughter (with her broken toe) and mom sanded the stringers for the stairs that had been painted green.  We planned to stain those so we needed to get rid of the old paint.

The order with all the planks, railings, and supplies/hardware was delivered and I got to work. I set up the miter saw in the garage and began by making a temporary frame.

A temporary frame was made out of cheap wood around the deck structure and acted as a border for my planks so that I could keep the same 1/4″ gap around the whole thing to allow for expansion and contraction. Once the frame was built, I cut a scrap piece of wood to 1/4″ to be a spacer and used it as a guide for my planks to butt in to. I placed it against the frame as I installed the planks so that I could maintain that 1/4″ gap and keep it all even. 

Laying a plank down where it goes, I placed the spacer against the frame and pushed the plank against it.  I did this for each piece to ensure all the planks would be even around the edge. The temporary frame would be removed after the decking was all installed.

It worked like a charm!  The hardest part of this section of the deck was getting the planks on the saw to cut to size and then carrying the very long and very heavy planks from the front of the house to the back. Let me tell you that a 16′ piece of TREX composite decking is VERY heavy and if you are 5’2″ it is really awkward to move around by yourself.

But, where there is a will there is a way and I did just fine.

Every plank of decking is not square on the ends so I had to square off one end of each plank with the miter saw. Then I measured the correct length I needed and cut that, hoisted each plank onto my shoulder, and carried it to the backyard.

Yes, Tylenol would soon be my best friend!

What is the best way to attach Trex Decking?

I opted for the TREX hidden fasteners for this project and highly, highly recommend them.  They were a breeze to install and look amazing! The hidden fasteners make it so that you don’t have to screw directly into the planks and give it a nice, clean professional look.

You don’t have any screws showing at all!

See how pretty that is? Installing a deck is a lot of work and this makes it look SO GOOD!!

The result is a beautiful finish and professional finish to your installation.

If you don’t use the hidden fasteners, you have to pre-drill into each plank for each screw you want to add. You need to use those special composite screws with this type of decking and they don’t go in without pre-drilling. That is waaaaay more work. And why would you want to do that?

The planks took me a day and a half to install by myself using this method.

Do you screw or nail Trex decking?

Screw your boards down to the joists! Trex recommends two screws per joist and you need to use a composite decking screw. Don’t nail and don’t use a nail gun. Getting nails to go through the composite without bending will be a challenge and cause you more headaches to try it than it’s worth.

TIP** Get the composite screws that are TREX branded! There are a lot of composite decking brands out there. Don’t buy just any brand. A little bit later in this post, you will see why.

How do you join two Trex boards together?

I recommend spending the extra money and getting the hidden fasteners. You will be so happy you did.

Unless you are using the square edge planks that you would use on the stairs of a deck, the planks will come with grooves on either side of the board. The hidden fasteners have a piece that sticks out on each side (looks like a capital “I”)  that hooks into each of the planks in those grooves to pull two planks tightly together as you secure them down to the deck frame at the same time.

How do you install a Trex deck with hidden fasteners?

All you need for this part is a drill and a rubber mallet. Your fasteners will come with a bit to fit the head of the screws that also come with the fasteners.

1. To start: Place two planks across your joists and perpendicular to them.
2. Put the first plank where you want it and set one side of a fastener inside the groove along right where a joist is, then screw it down with the built-in screw to slightly secure it.
3. Move on down that plank putting one side of a fastener into the groove and loosely screwing it down at each joist until you have attached a fastener to each joist.
4. Pull your next plank towards the fasteners, lining up the fastener to the new groove.  One by one tap the plank groove into the fastener with your mallet and screw down a little more to secure it.
5. Don’t secure the screw all the way until the fasteners are all in the grooves.
6. Once all fasteners are holding both planks securely, tighten the screws down making sure that the plank has not been pulled away from any of the fasteners.
7. Next, add fasteners to the other side of the plank you just secured in place and repeat steps 3 – 7 until the deck is installed.

 

The rainy weather rotted a small area of the siding on the house that would touch the new decking so to match the beauty of the deck, I cut out the rotted area of the siding using my multi-tool, went under the deck (gross), and cut out a siding piece that the weather really hadn’t touched the same size as the rotted piece and just swapped them.  It looks so much better!

I also wanted the new deck planks against the house to fit under the siding.  The Trex decking was a little thicker than the previous boards that had been on the deck by 1/2″. So I had to cut any siding on the house that the new deck would go under to allow for the new planks to fit with the multi-tool.  I measured the thickness of the plank, marked the existing siding where I need to cut, then used a multi-tool to cut the extra 1/2″ off.

The new planks would slide right under the old siding.  Doesn’t the deck look so great tucked UNDER the siding?

 

What kind of railing goes with a Trex deck?

It’s my experience that you can use any rail system with Trex as long as you follow the installation instructions that come with it and be sure to secure it correctly to the deck or have it custom made.

When I was at Lowe’s I found that Trex railing was pretty expensive for what my parent’s budget was so I looked around for a different option. Instead, I found a prefabricated, matte black simple square baluster metal railing system  They weren’t Trex but that didn’t matter. I ordered them and had them delivered with all of my other supplies.

It was now time to install the railing system on the deck. It is actually really pretty even though it isn’t a Trex system.  And it is really easy to install (like really easy) and saved the cost of having it custom-built by a railing company. It is a great option to keep you within budget.

I got busy installing the posts and, if you follow the instructions, they are really simple to install.

How do you install railing on a Trex deck?

You cannot just screw your posts into your Trex or composite decking. The railings will come right out!

You have to add bracing underneath the deck with 2x4s so that the long 4″ lag screws will have something to drive into.

At the beginning of this post, I had shown you that I added braces across the joists where the railing posts would be screwed into. This project did not fall short of math and calculations. Luckily it was pretty easy to figure it all out as long as I remained patient.

I calculated where the railing posts would need to be screwed into the decking. Then I securely added braces made out of 2 x 8 studs with long wood screws around the whole perimeter where those posts would go.

The braces will ensure that when the lag screws go down through the deck planks they will also go through the stud and be secured.

It is also important to have the correct bit for your drill so you can drive the lag screws (not included) into the decking and the bracing.  You don’t want to do it entirely by hand with a socket wrench.

Luckily my parents had a bit that I could attach to my drill, but if you don’t have one, get one that will fit the head of the 4″ lag screws you will need to purchase separately. You will also need to pre-drill these holes through the deck planks.

I did have to do the last part of the driving by hand with a socket wrench. It was pretty hard and took a little time.

I used my level the whole time, on each of the 4 sides of the post as I slowly secured the 4 lag screws with the socket wrench to secure the posts to ensure that they were standing straight.  I had to shim the posts as needed with metal washers until the lag screws were tight and the posts were straight.

Not hard, but time-consuming to get it perfect.

The posts went in and then it was time to install the railings. They needed to be cut a specific length, minus a 3/4″ on each end, etc. to fit into the brackets.  Again, this isn’t hard as long as you take your time and read the instructions thoroughly.

It was all in the instructions and there was no room for error. We only had exactly what we needed in the order and these things are not usually readily available in-store. Remember it took me 5 weeks to get the supplies!

I have shared with everyone how much the deck railing cost and what I ordered if you want to check it out!

Having never done this before, I read and re-read the instructions very carefully and was SO excited when I did it just right.  I felt so rejuvenated and had a new pep-in-my-step because I DID IT!

I needed the help of my daughter to hand me my drill once I got a railing set and it did take one entire 10-hour day.

I used the miter saw to cut the aluminum railings. Be sure to use ear plugs. It is loud and I am pretty sure that I scared off some of the wildlife in the woods. But they cut nicely and accurately.

It was easy but time-consuming with most of that time reading, re-reading, measuring, and checking the measurements again and again before cutting.

**Something to Note: there is a video on YouTube on how to install this exact system and it was made by Lowe’s which is where I bought the railing. But, the instructions on measuring and cutting on the video are actually incorrect so please follow the written instructions that come with the railings! The comments have been turned off on the video so I just happened to watch it so many times that I figured it out on my own.   Luckily I caught that incorrect detail before I cut the rails.

I felt like I was 100 years old by the end of day four, but OH it looks amazing!

Can I use Trex for stair treads?

The answer is YES! You can do your whole project in Trex. But be sure not to switch out to a different brand mid-project, and don’t use any composite screw other than Trex because it really does matter. And be sure to buy the square-edge planks since they won’t lock together on the stairs. They are a lot prettier than the ones that have the grooves. The square-edge offers a nice, clean look to the front of the stair treads.

Now was the time in my project for me to do the stairs.

OMG the stairs. It would prove to be the hardest part of the whole build. I’m not sure if it was really that hard or if I was just tired. I was going on days 5 and 6 of the project and had a deadline because I would be leaving to go back home soon.

I ended up having to take the stairs apart and reinstall them. I had to remove the stringers (the wood part that looks like alligator teeth that support the stairs) and cut a section off to eliminate one of the steps that sat on the ground, and then reattach them.

I dug them up with a shovel and made a huge hole and then had to reinforce the bottom of the stairs. In hindsight, I should have just bought new stringers the correct size. They aren’t that expensive and would have saved me some extra work.

I got the stringers cut down and reinstalled as well as braced for the posts that would sit at the bottom of the steps.

I wanted to cry. I was so tired and that was so unexpected. Despite showering at the end of each day I felt so dirty and so, so sore. But I had to keep moving forward. There was no turning back.

Once the stringers were installed I began to install the planks on the stairs.

I ran out of the TREX screws halfway through so I sent my parents out to find me more composite decking screws.  They found some and brought them home for me.

You would think that one composite decking screw is just like another, but that is not true.  There were no screws available in the area. No store had them in stock and I was in the middle of the project. We thought that we could just use a different brand of deck screws but they ended up being a NIGHTMARE to work with. They were unforgiving and REALLY difficult to use.

**Something to note: The lesson in this is to be sure to use the screw made by the brand of decking you are installing. 

How do you install a Deckorators stair railing kit?

Once I got the stairs installed it was time to install the railing.

This was REALLY hard for me. Probably because I had already been working a solid 10 hours on the stairs that day. I should have called it quits and NOT started the stair railing that afternoon, but the deck railing went in so well that I thought it would be just as easy.

IT WAS NOT!

It was way more difficult, or maybe I was so tired that it seemed more difficult, and should have come back the next day to work on it.

Do you want to know what happened that brought me to tears and made me ugly cry??

Remember when I said these things are not readily available at the store and we had to order these items 5 weeks in advance?  Well, I cut one of the stair railings wrong. Totally wrong!

And I cried. Ugly cried. Sobbed. I don’t know if I was just so tired and sore and just wanted to be done or if I just felt like a complete failure. It was the part of the project that made me question every decision I have ever made, lol!!

But it was bad. I don’t remember the last time I cried that hard or my body hurt that bad. I was doing the project myself (with a little help here and there sprinkled in from others).

The lesson here:  Stop when you are tired. You will make mistakes and possibly even injure yourself when working with saws, etc.  Get a good night’s sleep and get after it the next day when you’re fresh.

My mom put things into perspective for me and got to work on trying to find the railing that I needed in stock to try again. After searching and searching she found a railing….a couple of hours away.  My dad volunteered to go get it. It took him two ferry rides and 5 hours to bring it back home.

When I woke up I felt so much better and was ready to read the instructions again and begin. I needed some help on this installation so I called on my daughter to help. She is really smart and I needed another hand and brain to work on the stair railings. Together we successfully mapped out the first railing and where I would need to cut.

There was absolutely, positively NO more room for error. And I was so terrified to cut the railings again. They really took some brain power!!

I measured a few times, just to be sure, did the math over and over in my head, and then held my breath as I made the cuts.

Sigh of relief. THEY WERE PERFECT!  I was back!  And then we had to go through the same thought process and work on the second railing.

You’re probably wondering why the stair railings were so difficult to install.  They come straight in one pre-built panel, but then they hinge to an angle so you can fit them to your stairs perfectly.

It is a genius idea and works well when you are patient and can think about what you’re doing. The railings need x amount of inches between the tread and the bottom of the rail so figuring that out was a little time-consuming.

Are Deckorators railings good?

My parents are so so so happy with the result. They have been in since June 2022 and they are still the exact same as when I installed them!

Anything you install in Seattle will have to hold up to the rainy weather the Pacific Northwest offers most of the year and they still look beautiful.

They were exactly the look we wanted for the deck. The matte black color looks so good with the color of decking we chose and the simple square spindles give it a nice clean look.

We spent a large chunk of the budget on the Trex, which really mattered. We wanted a specific color and that cost a little more so the railings are a budget-friendly option and really easy to install with the exception of the stairs. I attempted to install the stair railings after an already exhausting 10-hour day installing the actual stairs so in the beginning it was rough! But after a good night’s sleep, I was able to clearly think and process the installation.

I pretty much did the entire installation by myself from beginning to end with the exception of a helping hand here and there so it is possible for one person to install the system.

The instructions on the video promoted by Lowe’s were actually incorrect in what it says for the cut measurement, so read the instructions instead of relying on the video to walk you through it. Now I can’t remember what the issue was, but it tells you to cut off more than you are actually supposed to cut off.

All about Trex Fascia Board

After the railing went in it was time to install the TREX matching fascia board around the perimeter of the deck frame. This would take the deck to a whole new level and finish off the perimeter of the deck beautifully.  I wanted it to look really substantial so I opted for a 12″ wide board. They were heavy and my mom ended up helping me as much as she could with them.

The fascia board was installed to cover the joists, make the perimeter of the planks look finished, and make the deck seem more substantial.

There were a few hiccups, mostly because we were using the off-brand screw from another composite deck line and that was causing most of the issues.  But, we figured it out and got them installed, and WOW! They look great!

 

The stair railing and the fascia boards took us all of day six but we finished it, cleaned up, and put the furniture and new fire pit on the new, beautiful deck!  That night we enjoyed a cool evening out by the fire with wine and laughed about all the things that went wrong while simultaneously admiring the beauty of their new space.

We found these awesome solar post topper lights and chose to use them in lieu of the ones that came with the railings. They were the perfect fit, are so cute at night, and give some additional comfort and warmth to the wooded retreat. My mom wanted a subtle light on the deck and these were perfect!! They just sit on top of the posts and light up when the sun sets.

YOU CAN DO HARD THINGS! Something always happens, that can be expected, and DIY can be hard.  It can challenge you, excite you, deflate you, and reward you all in one run.  But it is so worth it!

Be sure to check out the before and after in my Final Reveal including a list of everything we ordered, and cost breakdown of our Trex deck.

 

Until next time, stop waiting. Start creating!