Replies

1. 
   rez | Nov 11, 2002 08:12am | #1

   I like the layout. How much height space will be beneath the deck?

    Let the thunder crack and the waves roar.

    We're going on.

1. 
   pdelvis | Nov 11, 2002 04:24pm | #5

   The height space beneath the deck will be 9 1/2 '

2. 
   FrankB89 | Nov 11, 2002 08:31am | #2

   I don't have my beam span table handy right now, but I think you're good to go.  If you have concerns and want to effectively shorten the span without actually shortening it, you can install knee braces to posts below if that is feasable. But, while your description of what you want to do is pretty clear, it would help to better understand the existing joinery and structure.

   If this is an old traditional timber frame structure, of greater consideration is the beams perpendicular to your proposed beams/joists and the load they will be picking up...and how you'll be joining the new to the old.  One aspect of the old timber framing is the amount of structural wood that is removed to accomodate good, attractive, functional  joinery. You have to be cautious about where to remove wood and how much....

   You probably know all this, since you've been living with it for awhile....hope an engineer doesn't expect you to start bolting a bunch of steel into the thing.

    

3. 
   Piffin | Nov 11, 2002 08:46am | #3

   I'm thinking this is just bareley adequate materiaal for the span. I don't really know if it is clear #1 or select or rat knot crappy firewood lumber. Older stuff is usually found with some flaws and joinery is critical. Every nail hole might need to be predrilled because it may be cured quite hard. You might have a hard time getting an engineer to certify the design. I have had that trouble in the past because the books don't have design values for used old lumber so judgement calls come into play, depending on his familiarity with old product.

   Another concern that rears its head is the stair openning. Even though you report a reduced span in a certain area, the header transfers all that load stress to the next joist in line which is why we alway double that joist or in some cases triple it. I often see folks in heavier timber frame neglect to acount for this and over work that joist, assuming that because it is a big boy that it is big enough. Don't assume and you won't get hurt.

   .

   Excellence is its own reward!

   "The first rule is to keep an untroubled spirit. The second is to look things in the face and know them for what they are." --Marcus Aurelius

1. 
   pdelvis | Nov 11, 2002 04:19pm | #4

   Gentleman,  Thanks for the rapid responses.  The picture that is starting to emerge is that we will run two beams for the bridge--Running perpendicular to the bridge will be another beam (6" X 8") or a doubled joist that boxes out the stairwell.  The entire thing will get filled in with 3 X 9 joists.

   The alternative is to run all of the joists perpendicular to the span.  Use one large beam on the leading edge and run joists from this beam to a ledger bolted to the wall.  To me this seems to place too much faith in a beam that is handling the clear span.  It will likely have a great deal of bounce.

   Knee braces are a great idea--however the exisiting posts are going to line up with the stair opening.  And the beams in either scenario will sit on other beams--with no posts underneath.  I do need to think about how the load is ultimately transfered to the posts.