Saturday, September 25, 2010

Adventures in Deck Building, Or How Not To Build A Deck

So not only have we been working on our house over these past years, but also my mother-in-law's 1950s ranch.  She has two brand spankin' new bathrooms and a laundry room accessible from inside the house thanks to her son, with some help from me.  A couple of weekends ago, it was time to replace the deck.  It had gotten a little bouncy in places and she's getting ready to have the house painted, so it was time.  The challenging part of this, was that we weren't replacing the whole deck, just the old part that lays between the ramp and newer section of deck built by the Volunteeer Services Program of Elder HomesThat meant that the new section of deck we were building had a well-defined area and height that we had to match up with. 

As we started to take the old section of deck apart, it became pretty clear why the deck was bouncy - fewer than half the floorboards were still attached to the joists.  That made pulling the floor up a breeze, but wasn't a very good indicator of the future safety of the deck.   The posts were still solidly placed in the ground, but they pretty easily broke off at deck level.  The joists were harder to remove because they had been tied into the joists of the house.  Now, this was no easy feat, considering the deck was a relatively new addition, completed 20 years or more after the house was built.  All of the boards used in the deck, which we think was last replaced in the late '80s or early '90s, were still solid.  It was the construction that was the problem.  And that leads us to:  

How NOT To Build A Deck:
  1. Use nails that will rust out!  Most all of the nails on the decking were gone, victims of weatherization.  That made the deck easy to remove, but not so safe. 
    THE FIX:
    Mechanically galvanized or stainless steel nails won't rust and won't react with the chemicals in the pressure-treated lumber typically used on decks.

  2. Notch the posts to accommodate the deck structure - the more the better!  All of the posts had been notched so that either half or 3/4 of the post was gone where the joists met the post.  That created a spot for water and bugs to get in, weakening the post.  So though the ground-rated pressure-treated posts were still all solid at ground level and firmly placed in concrete in the ground, they had to be replaced to make the new deck because they were easily broken off where the cuts had been made. 
    THE FIX:  Use lag bolts to bolt the joists to the posts, leaving both the joists and the posts completely intact.  Be sure to use galvanized or stainless steel bolts to keep the bolts from reacting with the wood or the weather and rusting out.  
  3. Remove the sill band so that the deck joists can attach with those in the crawlspace of the house!  Okay, so this explains all of the mice and insects they had been dealing with over the years.  There were just big gaping holes stuffed with insulation where there should have been a ledger board.  Also a great place for moisture to get into the house. 
    THE FIX: We removed the joists that had been nailed in place under the house, insulated the space, replaced the sill band, and added a ledger board.  All of this was screwed into place with lag bolts.  The joists were then attached to the ledger board with joist hangers. 
    Joist hangers are the typical way of attaching joists to ledger boards today.  They're galvanized metal pieces that fit around the base of the joist.  A whole host of nails are required to fasten these puppies, and all of that nailing has to be done with good old-fashioned brute strength, but it makes the deck more solid and longer lasting.
  4. Set the stair stringers directly in concrete!  These did not fair as well as the posts, because of the nature of them being 2x instead of 4x, the natural cuts in them that make them stringers, and the fact that they aren't made of ground-rated lumber.  Bugs and moisture got into the wood so they broke off at the ground level as soon as the steps were removed.
    THE FIX:  Set the stringers ON the concrete instead of IN the concrete.
  5. Make the railings climbable!  Okay, in defense of the first deck builders, these rules have changed over the years as building codes have changed and you should check the codes in your own area.
    THE FIX: In our area, if the deck is more than 3 feet off the ground, it needs railings and if it isn't more than 3 feet off the ground and has railings, the railings must comply with the building code.  We opted for the railings, though we didn't have to, because they would help the new section of deck tie in with existing sections better.  Rather than using 3 horizontal boards like was on the old deck (basically a ladder), we used vertical 1x2s set the width of a 2x4 apart.  This meets the regulation of not being able to pass a 4" ball (or a child's head) through the railings.
We finished the deck, with help, in 2 1/2 days.  If you are thinking of building a deck yourself, there are a lot of great resources out there.  Check out Family Handyman's website  or the books below for step-by-step instructions.


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