Trying to build a deck. I looked in the basement of my house. My house
appears to be built without a rim joist. There is just wood i-beams
that sit on top of the foundation. Then plywood on the outside of the
house. How do I secure a ledger board?
The building code doesn't seem to allow a free standing deck because
the posts need to be 4 foot from the house.
I've read something about blocking but I've been unable to find a
detailed description of how to accomplish this.
On Mar 12, 2:16 pm, email@example.com wrote:
re: The building code doesn't seem to allow a free standing deck
because the posts need to be 4 foot from the house.
You could build a free standing deck if you cantilever the joists or
support them with diagonals. Just make sure you use the correct size
joist based on the cantilever and support beam spacing. I'd say it
couldn't hurt (except in the wallet!) to use 2 x 12's for a 4 ft
cantilever which would help eliminate and deflection or bounce at the
end of the joist.
This site has some hints and tips on joist sizing for cantilevers:
My advice would be to talk to your local government agency that issues
building permits. They are there for your benefit. They can connect
you to an inspector that will be able to offer suggestions to fit your
specific situation. It may cost a few dollars for a permit but it can
save you hundreds, maybe thousands, of dollars in repairs and
On Wed, 12 Mar 2008 11:16:40 -0700 (PDT), firstname.lastname@example.org wrote:
On Mar 12, 1:16 pm, email@example.com wrote:
Is it possible that from the basement you are seeing an LVL rim?
(similar to a microlam beam only not intended to carry a load). They
look similar to plywood or OSB. It seems fairly unusual (from my part
of the world) that there would be no rim (or a treated mudsill on top
the wall). If you know the thickness of the wall, you can measure
from the face of what you see to the edge of the wall and get an
estimate of the thickness of what you are seeing. If it's an LVL rim
board you should be reading a thickness of 1-1/2 to 1-3/4".
If indeed there is no rim another possibility for the deck addition
would be to extend your deck joist through the wall and over the top
of the foundation wall just like your floor I-joists are. We have
done that regularly over the years for a variety of reasons
(especially short span decks/balconies when we don't want posts at all
- they are cantelievered from the building).
I'm assuming you would be removing siding anyhow to place your ledger
board. Now you would have to do some additional work - including
removing that plywood rim (if that's what it is). You would want to
add squash blocks to the web of the I-joists so you have a good
surface to anchor your deck joists. The deck joists are set tight to
the I-joists (with the squash blocks filling what would have been a
void between them. Then you add solid blocking between each set of
floor-joist/deck-joist combinations under the wall above (almost like
a rim joist would have been). Of course I haven't mentioned that your
floor and deck joists are going to be different heights (at least
slightly) and you need to decide if you want them flush at the top or
if you want the deck stepped down slightly. We have snow in my world
so we usually opt for stepping the deck down slightly even though it's
not handicapped friendly (it keeps melting snow from sneaking into the
patio door). The approach you take will require some additional
blocking to keep everything solid. One more thing. Don't extend your
deck joists more than 12" into the house. In the old days there used
to be codes about "over-extending" lapping joists more than a foot
past the bearing point. I don't really remember what that was about -
probably something to do with warping, cupping, etc.
I would make a sketch of this for you if I could. I think a detail
drawing is worth a thousand words. I just joined this group today and
need to figure a way to share sketches efficiently if I'm going to
hang around - I tend to be visual. Good luck, I would be interested
to see some followup as to how this unfolds.
On Mar 12, 4:10 pm, firstname.lastname@example.org wrote:
re: need to figure a way to share sketches efficiently
Find a website to which you can upload your sketches and post the link
in this group. Based on the multitude of ways people read this group.
I doubt you could come up with a way that all of your sketches would
be viewable (correctly) in the newsgroup.
Hey, good idea - which inspired me to use my head! How about a link
to a Truss Joist Document and save me the time of making my own
sketch. The link below is to a PDF detail book. In the middle of
page 5 is a diagram that is closest to the situation in question.
They are dealing with true cantelievers which is not the question
here, so imagine that the outside end of the deck is supported by a
beam (etc) and you can ignore the reference to a 4' maximum
canteliever. What is most important is that they show blocking
details, etc., and how you need to deal with a "run-through"
situation. You will also have to "imagine" how your treated deck
joists actually fit into this sketch rather than other I-joists.
I suppose if this isn't a practical approach to sharing details
(hopefully the truss joist people don't mind). I could post custom
details on my own web site (but I don't want to be accused of
On Mar 12, 4:10 pm, email@example.com wrote:
By golly I think you're right. I took a closer look. I went to
Google images and looked up plywood. It's definitely not plywood :)
lol. I did the same thing with LVL and it looks more like that LVL.
Also after taking a closer look it appears that this board doesn't go
all the way up the way (I can see the small crack between it and the
floor. So yes, this must be a LVL rim joist! Eureka! This is making
much more sense now.
Thank you so much. I've been banging my head on this one all day :)
I am not sure if it would be a good idea to bear on the existing walls,
since your foundation was not designed originally to add half of your deck
load to it.
Staying 4 feet with the new posts is a great idea, since you wont be
disturbing the existing foundation, you can get a little closer. I dont
know of any code that requires you to stay away this far, but while you
want to attach to the existing structure for lateral stabilty, you want to
refrain from adding loads to it. here is a link for you
If the foundation has been calculated to withstand additional loads, you
can bear directly on the foundation over treated lumber using proper
methods, each individual joist can be attached using joist hangers. there
is a requirement that infills be installed between these joists, that
seems to have been averted.
This is what ijoist offers for rim board stability and lateral support:
Look at exterior deck attachment for detail view!
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Bill, you're responding to another one of those dimwits at that
homeowner's spam site that post looooooooooooong after the fact. The
question about the deck is from more than 2.5 years ago. Probably a
safe bet that it's no longer an issue for the OP, eh?
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