I built a deck last summer. I went synthetic simply to avoid the almost yearly task for pressure washing and staining the deck. Wood is porous and if I didn't keep the deck sealed the kids would walk on it with muddy boots and the mud would soak in staining the boards for months. We have real black mud/dirt and it looked pretty bad.

I am not a huge fan of the synthetic. It seems to scratch easy and it gets pretty hot in the direct sunlight... can't have it all I guess.

I dont know anyone that has a nice 5/4 deck. They work for a hunting shack or a small landing but I can't say I have ever seen a full sized deck built out of the 5/4 stuff.

 

Looking at the strength rating it’s pretty tough. I would think 5/4 with 16” joist spacing will be plenty strong and stiff.

 

I prefer the rounded edge 5/4 boards. To me it just looks cleaner. I did my entire 24'x30' deck in 5/4 cedar 4 years ago and couldn't be happier with it.

 

Another vote for synthetic material with joists 12”on center.

 

I have always done 5/4 on 16" on center joists. This is with the decking running 90 degrees to the joists.
If you run the 5/4 decking 45 degrees to the joists, the joists should be spaced 12" on center or space the joists 16" on center & use 2 x decking.

 

I’d go with green treated 5/4 . Don’t see many decks decked with 2x6s around here.

 

If you are willing to pick through some boards, both Menards and Home Depot sell "Thick Deck." It's rounded and a little thicker than 5/4 (which is actually 1") but also cheaper. Whatever you use, assuming it's treated, it needs to dry several months before staining or it won't take it

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I don't think I've ever seen a deck with 2x6's instead of 5/4" boards

 

5/4" decking will probably cost more but will far outlast 2" x 6" lumber. Just make sure you put it down right side up.

 

I agree. Although at the time, the cost was a wash if I recall. And I priced the deck floor with both 5/4 and 2x6.......
We have what I consider to be an enormous deck, a touch over 1,200 sq. ft. It was built in 2010 and added onto to mostly surround the pool in 2012. The floor is all 2x6 construction. The top board of my railing is 5/4 deck boards. In the last few years, I seem to replace some 2x6's every year. The 5/4 boards still look just fine, no punky spots, warping, etc. If I did it today, I'd use the 5/4 deck boards for the floor.

 

Putting right side up is not always possible, because the right side is not always best side.

 

Once the sides curl the so called good side will look worse, IMO.

 

I was curious and just checked Lowes for 2x6 & 5/4 pressure treat. Couldn't find #1 for 2x's but 5/4 round nose decking was a buck cheaper than a 2x !!

Unless OP is planning on thousands of people walking on his deck every day, I think 5/4 will work just fine and last at least 30 years! Stairs are another story as most people slide their feet onto a step creating a wear pattern. I'd go with 5/4 deck with 2x6 stairs.

Aside from putting the correct side up, install it quickly! Letting if sit & dry will also let it warp & twist. Bob

 

Unless OP is planning on thousands of people walking on his deck every day, I think 5/4 will work just fine and last at least 30 years!

With today's junk, not on a bet, IMO.

Stairs are another story as most people slide their feet onto a step creating a wear pattern. I'd go with 5/4 deck with 2x6 stairs.

I went with 4" x 12" x 48"

 

My front deck (480 sq) has 2x6 decking and the rear deck (300 sq) has 5/4 decking, both 16" on center. You will get most of any bounce on a deck from the span/size of the joists, not the decking, so one up your joists for a sturdy deck.
Quality wise, I prefer the 5/4 decking. It doesn't seem to check as easily as the 2x. Also, the 2x seemed to shrink quite a bit length wise the first few years, to the point were I have end gaps exceeding 1/2 inch. Some of this may be because the contractor used nails on the front deck and the guy who did the back deck used screws.
I have been contemplating re-doing the front deck. Can't decide whether I should just try flipping the boards for right now, or get new decking (5/4). New decking would mean I have to redo some work on the skirting, stairs and thresholds.
Any new deck I may add out back would definitely be 5/4.

 

When installing 5/4 pressure treated decking, don’t leave a gap between boards. They will shrink to the perfect gap all on their own. If you gap the boars, 6 months later you’ll have unsightly very large spacing. I’ve got a 25 year old 1000 sqft deck and still looks great after recently power washing it and painting it for a refresh so it looks virtually new. When I built the deck, I used SS square drive screws. They always looked great (nice and shiny) and easy to remove to replace any boards that rot prematurely.

 

 

yup, #1 5/4 PT with the correct side up (bark side up) and SS screws is the best way to go IMO if you don't like composite materials or can't afford it.. If the decking is upside down the SS screws will pop and you will not be a happy person during winter months when the curl and screw heads gouge the crap out of your shovel if you do indeed shovel your deck off of snow never mind that jolt to your elbows. MY decks around the house are 37 years old and after pressure washing they look brand new, (about every three years). I also did not stain or paint the decking boards.. I find that painting PT only helps to hasten the deterioration of the wood. Our pool decking is a composite, had cedar and it rotted in less than 7 years and that was treated with Thompsons. Still have the railings/balustrade cedar and that gets treated with Thompsons ever few years and that's still in great shape.
Bear in mind I picked out my decking and did not let the lumber yard just grab what they could to full the order so no large knots to be seen in my decking at all. We always picked our own lumber out for decks and loaded it on my work trucks or trailer.
I see so many decks with the decking up side down and some even nailed with finish nails and air nailed… FAIL...

 

The new deck we put on we went synthetic but it is small so cost wasn't much of a factor. It isn't really a deck but just a means to come out the patio door, make a turn and down a couple steps to the cement patio.

Back to your question..

I prefer the rounded edge. You can hand select 2x6 but depending on your source, I always seem to find a lot of knots in them. If you need a lot of them that can be time consuming. Another reason for synthetic is no knots. Really it comes down to which would you want to walk on if you ran out there in bare feet. Of the two you mentioned, I would say the 5/4 deck boards but local supply options might change that depending on the quality of the materials.

 

When I did my deck, I had quite a few 5/4s that were bent. I installed those by butting the smallest radius end against the installed board for at least a couple of joists (4 screws) and then pulled the far end until it was butted up and then used a large C-clamp on the nearest joist to act as a stop to keep the board butted. Then screw everything down.

Also, I never paid much of any attention to the cup other than to place the board concave up if needed so that I could screw the edge down against the joist. I didn't want to have a 'humped' deck, and I found that the natural cupping tended to cause the screw head to recess slightly as the board tried to lift up at the edge. So I guess I installed my boards against conventional wisdom. However, maybe this worked for me because I predrilled holes in all my boards so that the screw threads only engaged with the joist and only the head was holding the board down.

 

I hear you on the cost of synthetic and not all synthetic lives up to the manufacturer's claims, as evident by the numerous class action law suits that have been brought.

5/4, assumed "green" treated, will shrink significantly at first and that will create some maintenance issues. It will cup to a degree with time, no matter how you fasten it. The grain will lift. It will split. Unless plan on staining it and performing a maintenance coat every 3 to 5 years, depending on the sun exposure, it will turn an ugly greyish silver. You won't gain anything by utilizing 2 x 6 and the cupping may be more pronounced.

I did mine with "Brock Deck". My dock has "Brock Dock" decking, which is the same other than the face pattern. I purchased my first dock in the early '90s and spec'd the Brock Dock decking. It is out in the weather 365 days a year and intense sunshine in the summer. It still looks as good today as the day I purchased it. So I was sold on it for my deck, despite its crazy cost. I have about $75K into my deck and that was all materials, as I built it myself. About $35K of that was just for the synthetic decking and the railing.

 

Nice, very nice, but no pitch and putt off the deck???

 

We don't get Southern Yellow Pine in my neck of the woods. We use synthetic, cedar, or spruce usually. Synthetic is very expensive and really heavy, Cedar has some great rot and insect resistance properties, but is also very expensive. Most people use pressure treated spruce, or as it is also known 'PT'. I have several decks on my property. The longest is 10'x52', another is 16'x24, and the last is 12'x12'. I like the 5/4 PT with an under structure of 2x8PT on 16" centers but I've put them in a herringbone pattern on 12" centers too. The top deck boards usually stand up to 25 years of fairly hard use then I replaced just the 5/4PT. Square drive screws are the norm here. We buy them painted either green or brown to match the colour of the pressure treating on the decking. Stainless steel sounds pretty expensive for deck screws. I'd be interested in seeing pictures of your project. Good Luck.......
PS. Martincom, that is a nice deck, thanks for the pictures of it..

 

I'm a fan of 2x6 decking. I've got close to 1000sqft of deck behind my house and it's all 2x6 decking. Its held up great and hasn't shrunk nearly as much as I expected it to.

Ive never met a synthetic deck that didn't feel soft or spongy underfoot. I'm sure it can be done but all the examples I've been exposed to have never impressed me. The lack of maintenance side of synthetic is appealing but I prefer the look of stained wood.

This deck is going on 5 years now and it got a wash and coat of sealer at the end of last summer. It's free floating on concrete block and no dug footings. Still perfectly level and solid as a rock even after an number of cold winter's.

The next picture is what the upper level of the deck looks like that goes to the pool. It's the same age as the lower deck but hasn't been sealed in about 3 years. Washing and sealing it is on my list of projects for the spring hopefully before I open the pool.

 

Thanks guys. I decided on 5/4. The company I'm probably going to hire to build the deck uses the camo hidden fastener contraption. It puts the screws in through the edges so they are mostly hidden. The tool creates a 1/6" gap which is unavoidable. After shrinkage, I think it would open up to 3/16" gap? I think that's about normal, right?

 

After shrinkage, I think it would open up to 3/16" gap? I think that's about normal, right?

Probably about right and what I'd expect form the treated lumber we get here, in MN.

 

Have used both 2x6 and the 5/4 boards. The bending moment or flex is greater in the 5/4 but the 2x6 will pinch your feet walking on it barefoot. The difference in the sharp edge compared the chamfer on the deck boards when walking bare feet is significant. So much so that I only use 5/4 on projects.

 

I have an upper and lower deck. The upper one is smaller and I installed 2x6 plastic wood on it about 10 years ago. It has not caused me any grief. It looks as good today as it did when I installed it. Here is where I got it: Bear Board

Unless you get smaller pieces, they want to deliver it via a semi rig. So you have to find some place for the rig to park and then take possession of the product. The hassle of that is worth it though.

 

Kreg Deck Jig is worth a look, sets pocket holes in the board edge so the screw clamps down on the board with threads only in the joist. No nails or screw heads on the surface. Had 5/4 on prior houses and always a lot of effort to wash and restain. Put Azec on the new place, time will tell how that holds up but it gets good reviews when installed well. Smallish deck though so cost was bearable.

 

our front porch is made from 1 x 6 Ipe. Ipe is so much stronger than other woods so you can get by with thinner stuff.
We don't do anything to the wood, its supposed to be good for 50 years outside with no treatment.
Just let it turn grey naturally.