Joists ... open web or TJI

[gary]

Basement was poured yesterday and I need to order my floor package early
next week. I see people in the neighbourhood are using open web trusses.
My supplier has engineered a floor for me using TJI joists. I would like
opinions on what peeps here would use? I called my heating guy today and he
says he has no preference either way.

TIA
Gary

[Roarmeister]

Post by gary
Basement was poured yesterday and I need to order my floor package early
next week. I see people in the neighbourhood are using open web trusses.
My supplier has engineered a floor for me using TJI joists. I would like
opinions on what peeps here would use? I called my heating guy today and he
says he has no preference either way.

I have a slight preference for using open web trusses in the main floor
because it is easier to run the air ducts/piping/wiring across the open
spaces. True you can do the same with TJIs but you also have to cut into
the joists to create the holes, ergo more work. Are trusses more noisy or
prone to creaks than TJIs, that I don't know. 2nd floor - I'd use the
TJIs. You might find a slight difference in the installed cost depending
on your area, TJI's are trucked into my area from a goodly distance so
trusses are slightly cheaper.

[MikeP]

Post by gary
Basement was poured yesterday and I need to order my floor package early
next week. I see people in the neighbourhood are using open web trusses.
My supplier has engineered a floor for me using TJI joists. I would like
opinions on what peeps here would use? I called my heating guy today and he
says he has no preference either way.

I like using open web trusses. With open web trusses you do not
have to worry about cutting too-big/too-many/wrong-location holes
in the web of a TJI.

[3D Peruna]

Post by gary
Basement was poured yesterday and I need to order my floor package early
next week. I see people in the neighbourhood are using open web trusses.
My supplier has engineered a floor for me using TJI joists. I would like
opinions on what peeps here would use? I called my heating guy today and
he says he has no preference either way.
TIA
Gary

I'd second the preference for trusses over TJI's. The mechanical,
electrical and plumbing trades are not as likely to hack your floor apart.
If you have enough depth, and you talk to your mechanical contractor, you
could design a central duct chase for him and not have to drop any (or
minimal) soffits. Trusses...the better way to go.

[Robert Allison]

Post by gary
Basement was poured yesterday and I need to order my floor package early
next week. I see people in the neighbourhood are using open web trusses.
My supplier has engineered a floor for me using TJI joists. I would like
opinions on what peeps here would use? I called my heating guy today and he
says he has no preference either way.
TIA
Gary

Although the trusses will allow the subs to run their ducts,
pipes, and electrical more easily, I will tell you my experience.

I did a lot of insurance work for the past 20 years. I have
repaired numerous problems caused by failing trusses. They
tend to sag over time and we have had to go into perhaps 100
separate situations where the sagging or failing trusses have
caused problems ranging from unsightly to downright
catastrophic.

You can take your pick, but I would not have them in my house,
unless I glued and screwed plywood to at least one side of
them (which is what we usually do to repair sagging trusses).
The complete failures have to have more done to them. If
you glue and screw plywood to one side, then you have a TJI.

I can say that I have never had to repair a failing TJI. I
have had to repair them when they were installed improperly,
but not from failure of the joist itself.

Roof trusses tend to be OK, and I would use them (and have
many times), but you can keep your easy to work with floor
trusses.

[gary]

Thank you for that info. I think I will be ordering TJIs on Tuesday.

Post by gary
Basement was poured yesterday and I need to order my floor package early
next week. I see people in the neighbourhood are using open web trusses.
My supplier has engineered a floor for me using TJI joists. I would like
opinions on what peeps here would use? I called my heating guy today and
he says he has no preference either way.
TIA
Gary

Although the trusses will allow the subs to run their ducts, pipes, and
electrical more easily, I will tell you my experience.
I did a lot of insurance work for the past 20 years. I have repaired
numerous problems caused by failing trusses. They tend to sag over time
and we have had to go into perhaps 100 separate situations where the
sagging or failing trusses have caused problems ranging from unsightly to
downright catastrophic.
You can take your pick, but I would not have them in my house, unless I
glued and screwed plywood to at least one side of them (which is what we
usually do to repair sagging trusses). The complete failures have to have
more done to them. If you glue and screw plywood to one side, then you
have a TJI.
I can say that I have never had to repair a failing TJI. I have had to
repair them when they were installed improperly, but not from failure of
the joist itself.
Roof trusses tend to be OK, and I would use them (and have many times),
but you can keep your easy to work with floor trusses.
--
Robert Allison Rimshot, Inc.
Georgetown, TX

[Dan]

"Robert Allison" wrote in message

Although the trusses will allow the subs to run their ducts, pipes, and
electrical more easily, I will tell you my experience.
I did a lot of insurance work for the past 20 years. I have repaired
numerous problems caused by failing trusses. They tend to sag over time
and we have had to go into perhaps 100 separate situations where the
sagging or failing trusses have caused problems ranging from unsightly to
downright catastrophic.
You can take your pick, but I would not have them in my house, unless I
glued and screwed plywood to at least one side of them (which is what we
usually do to repair sagging trusses). The complete failures have to have
more done to them. If you glue and screw plywood to one side, then you
have a TJI.
I can say that I have never had to repair a failing TJI. I have had to
repair them when they were installed improperly, but not from failure of
the joist itself.
Roof trusses tend to be OK, and I would use them (and have many times),
but you can keep your easy to work with floor trusses.
--
Robert Allison Rimshot, Inc.
Georgetown, TX

I have the same choice for a loft over an unheated garage. I like the
ability to run ducts/pipes thru the open web joists, but have been puzzled
by the ability to insulate them effectively. Any thoughts on TJI vs.
openweb joists for insulation using fiberglass batts?

Thanks!

[Robert Allison]

Post by Dan
I have the same choice for a loft over an unheated garage. I like the
ability to run ducts/pipes thru the open web joists, but have been puzzled
by the ability to insulate them effectively. Any thoughts on TJI vs.
openweb joists for insulation using fiberglass batts?
Thanks!

Go with the TJIs and you won't have any problems.

With floor trusses, the usual method with batts is to insulate
between the trusses only, but to fill the space entirely with
insulation. This supposedly isolates the spaces between the
truss members.

[Dennis]

I did a lot of insurance work for the past 20 years. I have repaired
numerous problems caused by failing trusses. They tend to sag over time
and we have had to go into perhaps 100 separate situations where the
sagging or failing trusses have caused problems ranging from unsightly to
downright catastrophic.

Robert, in your experience, was there any common elements among the trusses
that failed and those that didn't? Was it related more to installation or
more to construction?

Thanks,
Dennis

[Robert Allison]

Post by Dennis

I did a lot of insurance work for the past 20 years. I have repaired
numerous problems caused by failing trusses. They tend to sag over time
and we have had to go into perhaps 100 separate situations where the
sagging or failing trusses have caused problems ranging from unsightly to
downright catastrophic.

Robert, in your experience, was there any common elements among the trusses
that failed and those that didn't? Was it related more to installation or
more to construction?
Thanks,
Dennis

It was directly related to construction. The joists that sag
seem to just slowly, over time, begin to succumb to gravity.
I have seen this most in areas with longer spans (16'+). I
believe that it is the inherent composition of the truss.
Each gang nail plate and each separate component each give
just a little, which accumulates to a significant sag of 1 or
more inches.

The failures have been from various causes. Some have a knot
or split at a critical point which fails and overloads the
adjacent trusses which also fail due to the added weight.
Others have been from settlement of the supporting walls,
which overloaded or caused the trusses to bear more than they
were intended to bear. Keep in mind that trusses are much
like chains, they are only as strong as their weakest link.
If you think of how many links a truss has, and every one has
to perform perfectly...

If only one gang nail, or one component fails, then the whole
truss will fail or at least sag. When you are dealing with
wood, it is not hard to see how this could happen fairly
frequently. Steel trusses do not have this problem because
the material quality is much easier to control. Wood has
defects and gang nails aren't always perfect or installed
exactly right.

The problem with them as I see it is that they are not
engineered with enough buffer to overcome some very common
circumstances. Most people don't want to have 2' thick
floors, so the trusses are made as small as possible to stay
within expected sizes. This doesn't give them much in the way
of forgiveness, so if ANY condition exists which exerts too
much force on them, they have a tendency to fail.

Dimensional lumber is much more forgiving.

[Dennis]

Robert, thanks for the response. Very interesting.
These are some of the things that never show up in the design or testing
phase. It's got me thinking.

Dennis

It was directly related to construction. The joists that sag seem to just
slowly, over time, begin to succumb to gravity. I have seen this most in
areas with longer spans (16'+). I believe that it is the inherent
composition of the truss. Each gang nail plate and each separate component
each give just a little, which accumulates to a significant sag of 1 or
more inches.

[Dennis]

Each gang nail plate and each separate component each give just a little,
which accumulates to a significant sag of 1 or more inches.

Meant to ask as well, how does steel webs do in comparison with the toothed
nail (Gang Nail) connectors?