An architect I
have known for over ten years contacted me a few days ago to help him solve
a problem on a custom home that he designed. The engineer that he used has
worked with him for over 15 years. The home uses Trus-Joist TJI floor joists
that cantilever out to form the balcony at the second floor. He has attached
a rim joist and showed the detail for the sheathing and finish on his plan.
The plan check
agency wants a detail to show how the manufactured glass railing is attached
to the end of the balcony. The Architect showed a conventional lumber
balcony framing and at the end a 4x rim joist. The mullion for the railing
was shown to be bolted down through the center of the beam at some uniform
spacing. The connection is a threaded rod with a plate washer and nut that
is recessed into the rim beam. The balcony framing (whether TJI or 2x) is
cantilevered out from the floor framing. The framing is covered with plywood
nailed to the top of the rim beam and joists. The sheathing is topped with
The plan checker
asked to show that the beam won't fail when a 200 pound lateral load is
applied at the railing 42" above the deck.
I reviewed his
problem and gave him my opinions;
1. There needs
to be a step down (1 or 1-1/2 inch) from the 2nd floor level to the balcony
to prevent water from flowing back into the house if there is no slope to
the balcony joists (the TJI's are not sloped). This does not seem to be an
issue in the TJI catalogs as it was a few years ago when they had step down
joists or cantilevers designed by extending Microlam's; sawn lumber or
Timberstrand joists extended in the web of the TJI's.
Agree completely, though I have always seen this done with microlams or some
other material that can be notched and / or ripped.
2. I believe
that the sheathing nailed to the top of the beam will prevent rotation in
the rim beam, but I see that if you pull on the railing there would be a
possibility that the connection of the beam to the end of the joists might
fail in pull-out strength of the connection.
3. I suggested
he recommend to his engineer that a Simpson LTT strap be used where the
failure is likely to occur. For safety reasons, I would use on one each
joist alternating between top and bottom so that the rim-beam is tied back
to the joists at top and bottom (where the couple is likely to
are on the right track. I would look at angle clips with bolts between
the joists and rim beam rather than cross grain tension. Or install
straps top and bottom. This is one of those areas where the contractor
will have have a fit with the usual "We have been just bolting the damn
things to the plywood for years....". The problem is that very often
these details are not engineered but are simply provided by the Architect
and no-one questions the validity of the design.
His engineer is
refusing to deal with this issue and the architect asked if I would
intervene. If this were conventional construction, I believe I could take
care of the non-compliant portions of the home, but in this case there is an
Engineer in Responsible Charge who is, in my opinion, required to complete
the plan check requirements.
he refusing to deal with the issue or indicating that it is not in his
scope? If they have worked together for 15 years I am surprised there
would be an issue now on this project. There might be other underlying
architect contact BORPELS to file a complaint against the EOR if a permit
can not be pulled until the corrections are complete?
could. Depends on the actual contract obligations and what the "real"
circumstances are. All kinds of nasty litigation could be enacted if
in fact the engineer is refusing to do something he is contracted to
do. I would be very reluctant to go down this road without a thorough
understanding of all the relative facts and positions.
architect hire another engineer to supply the calculations needed and have
the architect wet-stamp the details and calculations provided to
Yes, the Architect can hire another engineer for this component and then
assume responsibility under his stamp. Alternatively the other
engineer can provide a rail and rail connection design as a separate
deferred submittal subject to the EOR's approval. This is done all the
time for stair and related systems.
I don't think
this is such a difficult problem and don't understand why the engineer of
record will not complete the design. I've reviewed his drawings and details
and other than the coordination between the architect, who shows
conventional sawn lumber, and the EOR who specifies TJI's, the drawings are
light on details, but adequate compared to what I have seen out here.
think that for the reasons you describe above, there must be more to
it. The EOR may have had his fee haggled down to the ridiculous and
the exclusion of these detail items is part of the agreement. This is
one of the reasons I try and stay away from residential design. I am
always amazed that the realtor can earn a higher fee selling the place than
the engineer can justify designing it. Custom residential is an art
and extremely detail intensive if it is done correctly. Half of what
we see presented as "engineered designs" is pathetic. The fact that
the EOR actually provided an adequate design other than the rail issue is
another indication that there must be more to it.
state that you are "caught in the middle". I would simply step out of
the middle, present a fee and contract to perform the rail design as a
deferred approval or separate contract, and let the Architect, Owner, and
EOR work out the issues whether or not you are to
would be appreciated.
Dennis S. Wish,
Caught in the