Specs and materials:
12’ x 6’ floating deck with recessed piers
Concrete block piers (14, 12” base, 8” tall, heavy as hell)
2” x 6” pressure treated joists on 24” centers (7 x 12’, actual dimension 1 1/2” x 5 1/2”)
Galvanized flashing covers for the joists (78’)
2” x 6” pressure treated deck boards ( 13 x 12’, actual dimension 1 1/2” x 5 1/2”)
Galvanized joist hangers (14 for interior joists)
3” Treated deck screws (about 250 for the deck boards)
1 1/4” Treated deck screws (108 for the joist hangers)
3 1/4” Galvanized 16p nails (54 to nail the joists to the rim joist)
Concrete piers should give us a base that will last forever (my forever) and be easy enough to build around. We ended up setting 14 of them for the 12’x6’ deck. We don’t have the height available to put in a beam and joists as the land slopes down towards the house. We also decided to use treated lumber in contrast to the steel frame that we built the house out of. We want it to last a long time but it won’t need to be as permanent. We also decided against attaching the deck to the house. This way we could avoid the construction portion of having to cut and reconfigure the siding on the house to accommodate and attach deck.
|Pallets removed and bringing in deck blocks|
Although I don’t expect this to last 100 years, I did want to give it every chance possible. I had seen articles talking about protecting the tops of the joists from water accumulation damage. Where the deck boards meet the joists tends to hold water and will eventually erode the pressure treatment and rot the board out. Several projects I saw used rubber window flashing over the tops of the joists. I knew that the adhesive would eventually fail though and was not sure where that would leave us. I decided to use metal flashing instead. A galvanized steel umbrella over the top of the joist should offer pretty good protection and keep the water from rotting them.
I went to our local DIY center, Hooten’s, in Emory. I hesitate to call them a hardware store. They do way more than that. They have a full-service metal fabrication operation also. They will build just about anything you desire to your specs in addition to carrying a full line of wood, concrete and steel building materials. Think of it as a Home Depot on steroids. They took some simple 3” wide flashing and folded it to match the 1 1/2” top of the joists while I waited. Great service!
|Trimming joist covers to overlap|
I didn’t need to connect the caps to the joists. The deck screws going through them would be plenty. I think they came out pretty nice. The cost was about another $50 on top of the $500 for the rest of the deck materials. An extra 10% to double or triple the life of the deck seemed to be a good investment.
Laying the deck blocks and getting them level was the hardest part of the project. Each block is nearly 50lbs. We would dig out a location and set the block in to get an initial assessment of position. Then, we had to lift the block out of the hole 3-4 times to raise or lower with additional dirt until it was level. We got quite the workout that day for 2 old fat people. We didn’t want the blocks exposed at the edges of the deck so we set an additional joist at each end about 5” inside the frame. That way the block wouldn’t be proud of the deck on the perimeter but it would still give us good support at the ends of the deck. We also set the inner blocks the same way about 1’ in along the front so they wouldn’t be exposed. Hopefully, you can see that in the photos. Anyway, it explains why there are 2 joists close to each other on the ends. The additional joist member (flush together was to support a perimeter border deck board but we later changed our minds about that design. Too many complications with wet wood.)
|Joists in place|
We set a block at the entrance of the house to make sure the elevation was correct and then worked out from there. We had to set each block itself level and then raise or lower it to match the original block. We also left a slight slope away from the building of about 1/2” just to make sure water would drain off of the boards away from the house. We filled in much of the space between the blocks with dirt, being careful not to get up to the joist level, to discourage animals from camping under it. No guarantee but it seemed like a reasonable effort.
|Deck blocks in place and leveled|
Next, we built a perimeter frame with our 2x6s and made sure it was square by measuring across the diagonals. We mitered the ends so there would be no butt joints exposed. We used our framing nailer with the 3 1/4” nails to put the frame together along with some construction adhesive. We also picked up some wood preservative to treat the cut ends of the pressure treated members (joists and deck boards). Pressure treating rarely penetrates the entirety of the wood so cutting an end off exposes a vulnerable entry for insects. All I could find was a gallon, again at Hooten’s as HD & Lowe’s have stopped stocking it in the stores, although we barely used a pint. I guess we’ll have a lifetime supply. :)
|Each joist attached with joist hanger and then nailed from the outside. We had to stand the structure up to nail the backside closest to the house.|
Now we cut the inner joists and laid them in the blocks. We blocked up the perimeter frame and set it level and attached the joists with galvanized joist hangers. We used 1 1/4” deck screws to attach the joist hangers to the frame and nailed the outside frame to the butt ends of the joists with the nails as nails handle sheer forces much better than screws which tend to be brittle when stressed with side forces. Now we capped the entire frame with the water shields I had fabricated and got ready to lay the deck boards. We left about a 1/4” overhang on all sides with the deck boards and had built the frame accordingly. We laid the 12’ 2x6s (uncut) in place one by one and screwed them into place with 3” coated deck screws. The screws didn’t seem to even notice the metal flashing they had to penetrate. Be sure and set the crown of the wood so that it will create a dome on top of the deck boards instead of a cup. Hopefully, this diagram helps.
We set the straightest board we could find in the 1st position as it would set the pace for the others. We would screw one end of each deck board into place and then use a ratchet strap to pull it tight against the other boards as we went. The wood was still pretty wet from the pressure treatment so we didn’t set any gap. The boards will shrink up just a bit as they dry and leave about a 1/4” gap between the deck boards. We set one end of the deck boards flush as we went and left the other end of the deck jagged as boards are never the exact length from the mill. We’ll let this dry for a month or so and then pop a chalk line and trim them all even with a circular saw, again treating the ends after they’ve been cut.
|Finished deck. Nice project for 2 days. :)|
I later went back through and finished setting the screws into the deck boards. This burned through 3 batteries on my impact driver. I highly recommend an impact driver instead of a plain drill/screwdriver. You’ll understand why the 1st time you use one to drive long screws. My Porter Cable 20v never hesitated driving the 3” screws. Be sure and wear eye and hearing protection. Driving ~ 400 screws will take its toll.
Just a note on working with wood. Everything I had done before had been with steel. It is very exact, very straight, very precise in length and depth. Wood is exactly the opposite. It’s warped and bowed and cut to varying lengths and thicknesses. It swells (at different rates) when pressure treated and shrinks as it dries. Screws and nails don’t drive in straight as they have a tendency to follow the grain. Wood tries to arch as it continues to relax after it’s been freed from its tree form. Lots to consider. When I meticulously drew up our plans for this deck, I didn’t take into account that the wood would be thicker and wider due to being wet. I planned on 13 deck boards at 5 1/2” wide. Between the swelling and the fact that they just won’t lay flush against each other, I ended up with an extra 1” hanging off of the edge of the deck closest to the house. The reasonable thing would have been to run that last board through our table saw and trim off the inch. Instead, we hooked the entire deck up to a couple of trees in the yard and pulled it away from the house another inch with ratchet straps. (Incredibly heavy by now) If it don’t fit, get a bigger hammer! lol We were just too lazy to dig the table saw out of the storage building as it was buried with beekeeping supplies at the time. Plan accordingly. Either plan ahead and let your lumber dry for 3 weeks to a month before you start your project OR count on the room necessary for each board to be a bit wider than 5 1/2”.
We really enjoyed this project and will enjoy the deck even more over the next 30 years. Anything past that's a crap shoot - for us, not the deck. I hope it gives you some insight and helps you understand the factors in building your own simple deck. Best of luck, bless you and have a great holiday!