Building a Floating Deck

by dbenedetto in Outside > Backyard

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Building a Floating Deck

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My wife and I like to sit out in our front yard and socialize with the neighbors as they walk by. As you can see, the grass is dead, the dirt tracks everywhere and it looks terrible. So I decided to build a floating deck. After months of planning, calculating, and lots of prayer, I am finally ready to begin. I have never undertaken a project of this magnitude before and had no idea what I was doing.

Tools & Safety Equipment

PRIMARY TOOLS
* square shovel
* pointed shovel
* mattock
* pickaxe
* mini pick (garden pick)
* 72" level
* 2' level
* torpedo level
* laser level

SECONDARY TOOLS
* sawzall
* circular saw (skill saw)
* drill (1/2" & 3/4")
* chainsaw
* 3 lb sledge hammer (short handle)
* jacuzzi tub (for exhausted, aching muscles)

SAFETY EQUIPMENT
* face shield
* ear plugs
* ear muffs
* face mask
* work gloves

Supplies

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From Lowes:
* 6 PT 2"x4"x12', $54
* 2 PT 2"x12"x8', $40
* 2 PT 2"x6"x8', $15
* 2/3 yard/18 cu ft of sand, $48
* 8 3/8" x 2' rebar, ~$8

From http://www.advantagelumber.com/tigerwood_decking.htm
* 26 tigerwood 1"x6"x8' standard, $1.98/lin ft, $411.
* Box of 350 ss deck screws w/brown top $44
* Ipe sealer, 1 qt, $23
* Ipe oil, 1 gal, $60

Total about $700

I forgot to take pictures of the supplies other than the sand. :-(

Remove Existing Retaining Wall

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First I removed the existing blocks to use again as pillars for the joists.

Excavation

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Since I was repurposing existing retaining wall blocks to be used as pillars for the joists, I dug down about 6-7" (I wanted the dirt to slope away from the house). This accounts for 4" of block, and 2" of sand. I wanted the top of the blocks to be AT grade level which would give my deck a 4" step up.
The hardest part was removing all the roots left behind by a very vindictive jacaranda tree we had removed. One of which was 10-12" in diameter. Almost every swing of the pick hit a root. Then I had to use the mini pick to trace the root and cut it out below the new grade level. I used three packs of blades for the sawzall to remove most of the roots. For the larger ones I used the sawzall, skill saw and sometimes drilled numerous holes to facilitate sawing. Eventually I ended up buying an electric chainsaw from Harbor Freight for the real large one. I ended up wearing out two chains and finally gave up and left the rest of the root in the planter for "decoration". You can see it in the last picture. It was about 10' long, so I think since all that is left is this 2' I did enough work. Besides, I kept bumping the chain saw into the stucco wall. Believe it or not, but that really dulls a chainsaw chain very quickly. The pictures give you some idea just how prolific that tree was.

Since this an 8' x 12' deck, that is a LOT of dirt to be moved. TWICE! The first was the excavation and you can see part of the huge pile in some of the pictures. The second time was filling two large green trash cans and one large gray trash can every week for about a month.

Move Sprinklers

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There were three sprinkler heads hiding in the dirt. I capped one and moved the other two to where the new planter would be. You can see the two pipes sticking up in the pictures.

Set New Retaining Walls

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Now that I have excavated, I need to put in the new retaining walls on three sides: north, south and east. I used a pt 2"x6"x8' for the shallow north and south sides. I used two 2"x12" x8' boards for the east side where the planter will be. The pit was deeper there to insure the dirt sloped away from the house.
Pictures 1 and 2 show the south and north walls respectively. Picture 3 is the new east wall. You can see the two new sprinklers just east of the retaining wall.

I used the 6' level to insure levelness of all three walls and secured them with four 2' pieces of 3/8" rebar per board. I used the 3 lb hammer to pound each rebar 12" deep for the east wall and 18" deep for the south and north walls. Lowes didn't have any shorter pieces and I didn't want to go to the trouble of cutting rebar.

Laying Sand

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I now lay down about 2" of sand upon which I will set the pillars for the joists. By the way, 2/3 yard of sand (2 bags) is about 2000 pounds. That is a lot of work!

My wife filled two 5 gal buckets, and I carried them to the pit. A 5 gal bucket full of sand weighs about 80-100 lbs. Carrying two of those was a little TOO much for a 70 year old guy so I had Kathy fill them up only half way. It took twice as long to move all the sand, but at least my arms didn't fall off.

90 minutes later I smoothed out the sand and took the rest of the day off. Now I am headed for the hot tub for some very much needed r&r.

Setting the Pillars

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Each of these blocks weighs about 30 lbs and I set 24 of them.
I started in the south east corner and went west every 16" on center (picture #1). Then I went back to the s.e. corner and went north (picture #2). I layed them roughly every 3 ft for each joist. That is 4 per joist.

I leveled each block with the torpedo level then used the 2' level to level adjoining blocks and finally I used the 6' level to level the blocks in the X and Z directions and diagonally. I also used a laser level to insure proper height for each block.

Finally after 2-3 days I am now ready to start laying the joists.

Setting the Joists

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Sorry about the lack of pictures, but after about a month I'm getting very tired. As my wife said, "I'm finished, but the job isn't".

The reason I'm using 2"x4" for joists is simple. Since the pillars are 3' apart, I really didn't think a 3' span would be too much for a 2"x4" on edge.

I'm using 2.5" ss deck screws to attach the blocking to the joists for every pillar. My problem was how to screw in the blocks to the first joist next to the east retaining wall. The joist is only 3" from the retaining wall so that didn't give me enough room for the screw and the drill.

I solved that by laying out the blocks and marking their location on the joist. Then I stood the blocks on end on their respective pillars, and carefully set the joist on top of them. This allowed me to drill downward to attach the blocks. It worked!

The rest of the joists and blocks were accessible EXCEPT the last (west) joist which was 4" from the foundation of the house. I simply repeated the same process for the first joist. WOW! the end is insight!

Facia Boards

At this time I installed the two 1"x4" facia boards on the south and north ends of the joists. Sorry I forgot to take pictures, but you can still barely see them in the glamor shots and in the next step.

I installed the facias now because in the next step I need a 1/2" overhang for the southern and northern most deck boards.

Deck. Boards

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First I layed out all deck boards with 8P nails for spacers just to confirm my calculations. I bought a .5"x 6"x12" piece of foam at Michael's. Then I cut 1" strips and cut 1" pieces from that. I put one nail through each piece. This kept the nail heads up so they could be more easily removed when necessary. It's a little hard to see so look closely in picture #1. Picture #2 has all of the boards screwed down.

I maintained a 1/2" gap between the board end and the east retaining wall which can be seen in picture 3. This cleared the 3/8" rebar quite nicely.

For the west side I hid the board ends under the shingles (picture 4), and I put a 1"x2" over the board ends under the window. You can see the moulding in the last two pictures.

I love moulding, it covers a multitude of sins! :-D

It turns out that my calculations were only off by a quarter of an inch from north to south at the east side of the last board. This was easily compensated for by using 10P nails to space the east end of the boards and an 8P nail at the west end of the board. This is only a difference of 0.04". Not really noticeable but it added up beautifully for my missing 1/4" !

Then I started at the east end and started screwing the deck boards down. Since the boards are 5.5" wide I had enogh room to create a 1/2" overhang over the facia boards. This will allow me to install led tape lights under the south and north edges at some future time.
I put two screws at every other joist. This spaced each pair of screws almost 3' apart. I didn't want the screws to dominate the appearance of the deck. So I only have 4 rows of screws across the deck. While sitting down, only one row is visible. :-)

Knowing nothing of what I was doing, I can't believe how perfectly everything came out. The deck was level, the boards fit exactly and any errors were easily covered. I guess my prayers were answered!

The END!

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Now the deck is finished. I sealed the cut ends of the deck boards with ipe sealer then I used a paint roller with a 3/8" knap and rolled on the oil.

Although the deck is complete, I still have about 2 yards of dirt to dispose of, sod to lay, sprinklers and drip system, and the planter to finish. Time to celebrate!

Additional Glamour Shots

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These were taken after EVERYTHING was completed. The black thing in the n.e. corner in picture two is the umbrella stand. The gray thing in the planter in picture two is a fountain.

In addition, I just had to add some pictures of my cat who was such a big help.

Hindsight

I would advise you to put the deck boards down LAST. After EVERYTHING is complete and cleaned up. It appears that when disposing of the dirt and finishing everything else I ground dirt into the deck boards and ruined the finish. Now I have to refinish them. Oh well, given how well this turned out, I can't complain. ;-)

I chose tigerwood (a Brazilian teak) for its price and appearance. It is also very hard and will last about 30 years with annual oiling. That means it's quite low maintainence.

God bless you, David.