Building a 24' X 20' Deck on Steep Slope




TOOLS:                                                                                                                                                                                      SHOVEL, WHEEL BARREL, STRING, PLUMBBOB, SQUARE, 5 GAL BUCKET, HAMMER SCREW GUN, MITER SAW, DRILL PRESS, I USED A NAIL GUN, LOTS OF STAKES, SKILL SAW, SAWS ALL, DRILL, PAINT BRUSH, 2 WRENCHES, LEVEL, WATER LEVEL IS BEST, STRING LEVEL, ,,                                                                                                                                                                                                                              so this instructable will cost you around $15,000  if you have to purchase all materials, I'll try to get all materials right here, with approx. footage..  concrete 200 90lb bags, sonotube, 3 - 6x12x24  girders ( beams) 3 - 4x6x16 posts , 12 - 4x4x8 posts, 32 - 2x12x16 joists, redwood decking, 48 3/4" nuts,98 washers, 4 - 8' sticks of all thread , 24- 10' sticks of galvanized pipe 1/2",  pressure treating adhesive 4 cans, steel plates for post to girder connections, simpson concrete ties for footings, 50lb box 3in. gal. hot dip nails, box of deck screws, couple cans spray paint,                                                                                                             

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Step 1: Getting Started

ok it took me by my self nearly two days to lay out and square up the strings to mark my footings.   Once you get it all square dig the furthest corners first, set the sonotube hanging in the hole up off the bottom of the ground about 1 ft. so the concrete sluffs out as a footing then before it sets up push your simpson tie into concrete, level it make sure its still square with the rest.     then hang the girder from corner to corner then you can hang a string down from girder to mark the rest of your footings exactly.

Step 2: Joist's and Paint

Ok the three girders are set and bolted down ,    now paint all of the joist's with a green wood preserver, if you want it to last.                  now lay out your joist's start from one end and block each joist on all three girders as you go nailing everything, this should be the fastes part , the most rewarding,        

Step 3: Post Rails

then cut your railing post  so it reaches the bottom of your girders and block it in from the edge and through bolt them lay out is 8' or what ever your choice. after all the railing posts are in and tight start the decking from the furthest spot (highest spot)

Step 4: Railing

now the railing  tricky must be no more than 4" apart    take some of your red wood boards up on edge  and mark every 4" two at a time make them exact  drill press your holes not all the way through the board though and cut the 1/2 " galvanized pipe into 32" pieces (think that's the number) and paint them.  youll be able to figure the length by the height you want your railing.

Step 5: Then Stain It and You Should Be Good.

before and after        thanks for looking

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    7 Discussions


    1 year ago

    How did you tie into the slab? aren't you worried about moisture getting in between? How did you plan for that?


    2 years ago

    Beautiful deck. On a hillside or slope deck like this I would recommend Imus Cap for joist and beam protection against wood rot. Very easy to install.


    6 years ago on Introduction

    For maximum strength and durability, the posts and the railing posts should be one and the same

    1 reply

    Reply 6 years ago on Introduction

    yes that's very true but in this case they were 4x6 and
    I wanted more deck space. the posts have 4 through bolts in both directions they are sound.

    Iron Cowbell

    6 years ago

    Did you end up cutting off the uneven ends of the boards hanging over the right side?

    1 reply