Background: I'm trying to modify my attic a little bit in order to store
some things up there. Currently I'm busy fastening 3/4" plyboard over the
ceiling rafters (so objects to be stored won't crash thru the drywall
ceiling). However movement/activity up there is hampered by the fact that
the roof is supported by factory produced 2x4 trusses, as these are composed
of many cross members that switch back-and-forth at oblique angles between
the upper and lower rafter sections of each truss. It would certainly make
my attic storage efforts easier if some of these cross-members could somehow
be removed out of the way (that is... in such a way as to not compromise the
structural integrity of my roof, of course).

Therefore I'm requesting feedback on the following idea: 'Sistering' (i.e.
reinforcing with) 2x6s to the topmost rafters, followed by removal of some
of the supporting cross-members of said trusses. Not being a carpenter or
structural engineer of any kind, I'm seeking informed comments/advice from
others before going further with this.

Thanks.

Ken

You need a Structural Engineer.
TB

It seems like you're being careful about this; which is good.

"Never trust a truss" is what many firefighters say. When any of the support
members of the truss are compromised the strength of the entire truss is
compromised.

Trying to build attic space in a web of truss supports isn't going to be
easy. You'd probably have a safer project if you just put your shelving
boards in the spaces on the trusses where possible. You don't want to start
cutting on any truss. I believe there are issues with doing anything to stop
the flexing of the bottom member of the truss (probably the ceiling joists
for you). There needs to be some room for movement with temp and humidity
fluctuations.

Ken Moiarty wrote:
Background: I'm trying to modify my attic a little bit in order to
store some things up there. Currently I'm busy fastening 3/4"
plyboard over the ceiling rafters (so objects to be stored won't
crash thru the drywall ceiling). However movement/activity up there
is hampered by the fact that the roof is supported by factory
produced 2x4 trusses, as these are composed of many cross members
that switch back-and-forth at oblique angles between the upper and
lower rafter sections of each truss. It would certainly make my
attic storage efforts easier if some of these cross-members could
somehow be removed out of the way (that is... in such a way as to not
compromise the structural integrity of my roof, of course).
Therefore I'm requesting feedback on the following idea: 'Sistering'
(i.e. reinforcing with) 2x6s to the topmost rafters, followed by
removal of some of the supporting cross-members of said trusses. Not
being a carpenter or structural engineer of any kind, I'm seeking
informed comments/advice from others before going further with this.

Thanks.

Ken

What you are suggesting would require re-engineering of each and every
truss you are killing. All the parts of a truss work together so if you
eliminate one, you have in essence eliminated them all.

--
Joseph Meehan

Dia duit

"Ken Moiarty" wrote in message
news:BYdwe.1819374$Xk.1125184@pd7tw3no...
Background: I'm trying to modify my attic a little bit in order to store
some things up there. Currently I'm busy fastening 3/4" plyboard over the
ceiling rafters (so objects to be stored won't crash thru the drywall
ceiling). However movement/activity up there is hampered by the fact that
the roof is supported by factory produced 2x4 trusses, as these are
composed of many cross members that switch back-and-forth at oblique
angles between the upper and lower rafter sections of each truss. It
would certainly make my attic storage efforts easier if some of these
cross-members could somehow be removed out of the way (that is... in such
a way as to not compromise the structural integrity of my roof, of
course).

Therefore I'm requesting feedback on the following idea: 'Sistering'
(i.e. reinforcing with) 2x6s to the topmost rafters, followed by removal
of some of the supporting cross-members of said trusses. Not being a
carpenter or structural engineer of any kind, I'm seeking informed
comments/advice from others before going further with this.

Thanks.

Ken



Ken,

Work with a truss manufacturer and their truss engineers. They have truss
design software that can run your project inside out and upside down. A
normal engineer can do it, but the truss manufacturers have the software to
work up calcs easily.

You might have to pay for this engineering, since you are not buying a truss
set.

David A.

"Ken Moiarty" wrote in message
news:BYdwe.1819374$Xk.1125184@pd7tw3no...
Background: I'm trying to modify my attic a little bit in order to store
some things up there. Currently I'm busy fastening 3/4" plyboard over the
ceiling rafters (so objects to be stored won't crash thru the drywall
ceiling). However movement/activity up there is hampered by the fact that
the roof is supported by factory produced 2x4 trusses, as these are
composed
of many cross members that switch back-and-forth at oblique angles between
the upper and lower rafter sections of each truss. It would certainly
make
my attic storage efforts easier if some of these cross-members could
somehow
be removed out of the way (that is... in such a way as to not compromise
the
structural integrity of my roof, of course).

Therefore I'm requesting feedback on the following idea: 'Sistering'
(i.e.
reinforcing with) 2x6s to the topmost rafters, followed by removal of some
of the supporting cross-members of said trusses. Not being a carpenter or
structural engineer of any kind, I'm seeking informed comments/advice from
others before going further with this.

Thanks.

Ken

NIX on the sistering.

Truss calculations are figured from the bottom of the truss. Just how much
weight are you planning on adding? any significant weight on the top of the
truss can spell disaster.


I use my attic to store empty boxes that are broken down. total weight,
maybe 50 pounds spread out over a 4x8 sheet of plywood.

In a previous post Ken Moiarty says...
Therefore I'm requesting feedback on the following idea: 'Sistering' (i.e.
reinforcing with) 2x6s to the topmost rafters, followed by removal of some
of the supporting cross-members of said trusses. Not being a carpenter or
structural engineer of any kind, I'm seeking informed comments/advice from
others before going further with this.



Ken:

STOP!!!!

What you are suggesting is a recipe for disaster.

1) It is quite likely that the trusses were NOT designed for attic
storage.

2) Cutting any truss members will void any warranty that the truss
manufacturer may have given or may be implied in your state law. In
other words if the roof collapses, you will have no legal recourse.

3) Rent a storage locker. It will be cheaper and much much safer.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA

David,
If I gave a truss manufacturer a careful drawing of an existing truss,
a manufacturer could tell me what loads it could support?
TB

wrote:

David,
If I gave a truss manufacturer a careful drawing of an existing
truss, a manufacturer could tell me what loads it could support?

A manufacturer will probably not even give you the time of day.

And I doubt they have a CAD system and/or expert that does finite
element analysis on the stuff they do make.

Look. They churn out the same stuff day in and day out. They're not
going to have expensive computer software (and an even more expensive
engineer) on staff to basically twiddle his fingers. They don't
change their designs often enough to warrant that sort of cost. Wood
trus engineering was worked out decades ago. It's not rocket science.

For liability issues no-one is going to look at your drawings and give
you a thumbs up or down.

In a previous post says...
David,
If I gave a truss manufacturer a careful drawing of an existing truss,
a manufacturer could tell me what loads it could support?
TB


Tom:

Most likely they won't take the time to deal with it. This is a common
problem, but the truss manufacturers don't really want to deal with a
homeowner on a single project where they are not going to sell anything.
The possible profit to them is too small, so they won't consider it.
This is especially true if the existing trusses are not ones that they
built in the first place.

Most structural engineers (including me) don't really want to be
bothered with this type of problem either. The liability is high for a
very small return. I'd do it for a regular client, but only then. The
cost of engineering services to analyze the truss and its connections,
then design a fix is simply not worth the money in my view. You could
rent a lot of storage space or buy and build a small storage shed for
the same amount of money.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA

You could rent a lot of storage space or buy and build a small
storage shed for the same amount of money.

If you're a half decent carpenter and you throw enough 2x4's at it,
you'll probably end up with something stronger than you started with.

If you use 1/4 bolts with fender washers and (or) #12 or #14 wood
screws and pre-drill the holes (and not nail anything together) you'll
have something stronger than the existing framework.

I bet your existing wood is full of splits because of the hack job
that is usually done when cutting rafters and pounding over-sized
nails in.

Do yourself a favor and make sure each and every rafter space is
ventilated out to your soffit overhang. Don't stuff the insulation in
there - let it breath.

"Ken Moiarty" wrote in message
news:BYdwe.1819374$Xk.1125184@pd7tw3no...
Background: I'm trying to modify my attic a little bit in order to store
some things up there. Currently I'm busy fastening 3/4" plyboard over the
ceiling rafters (so objects to be stored won't crash thru the drywall
ceiling). However movement/activity up there is hampered by the fact that
the roof is supported by factory produced 2x4 trusses, as these are
composed
of many cross members that switch back-and-forth at oblique angles between
the upper and lower rafter sections of each truss. It would certainly
make
my attic storage efforts easier if some of these cross-members could
somehow
be removed out of the way (that is... in such a way as to not compromise
the
structural integrity of my roof, of course).

Therefore I'm requesting feedback on the following idea: 'Sistering'
(i.e.
reinforcing with) 2x6s to the topmost rafters, followed by removal of some
of the supporting cross-members of said trusses. Not being a carpenter or
structural engineer of any kind, I'm seeking informed comments/advice from
others before going further with this.

Thanks.

Ken



You are joking aren't you???????????

Most residential trusses are designed to hold up the roof and the drywall.

Attic junk not included. Floor load not included.

Colbyt

Some Guy wrote:
You could rent a lot of storage space or buy and build a small
storage shed for the same amount of money.

If you're a half decent carpenter and you throw enough 2x4's at it,
you'll probably end up with something stronger than you started with.

If you use 1/4 bolts with fender washers and (or) #12 or #14 wood
screws and pre-drill the holes (and not nail anything together) you'll
have something stronger than the existing framework.

I bet your existing wood is full of splits because of the hack job
that is usually done when cutting rafters and pounding over-sized
nails in.

snip

Now I have seen some bad advice in this forum before but this ranks
right up there with the worst of them.

Harry K

"Ken Moiarty" wrote in message

It would certainly
make
my attic storage efforts easier if some of these cross-members could
somehow
be removed out of the way (that is... in such a way as to not compromise
the
structural integrity of my roof, of course).

Therefore I'm requesting feedback on the following idea: 'Sistering'
(i.e.
reinforcing with) 2x6s to the topmost rafters, followed by removal of
some
of the supporting cross-members of said trusses. Not being a carpenter
or
structural engineer of any kind, I'm seeking informed comments/advice
from
others before going further with this.

Crazy idea. Sure, there may be some method, but do you really trust a bunch
of us crazies on a newsgroup to tell you how to re-do your roof support?
Only way to know is to have a qualified engineer look at the situation. Not
knowing the spans, load, new floor load, etc, you can be in real serious
trouble with this.

Some Guy wrote:
You could rent a lot of storage space or buy and build a small
storage shed for the same amount of money.

If you're a half decent carpenter and you throw enough 2x4's at it,
you'll probably end up with something stronger than you started with.

I wouldn't bet on that. The odds of him messing up the structure are
very high.

If you use 1/4 bolts with fender washers and (or) #12 or #14 wood
screws and pre-drill the holes (and not nail anything together) you'll
have something stronger than the existing framework.

Stiffness attracts load. You stiffen up one section of the truss and
another area, maybe on the opposite side of the house, will have its
loads drastically affected. You're intentions are good, but you're not
helping this guy.

I bet your existing wood is full of splits because of the hack job
that is usually done when cutting rafters and pounding over-sized
nails in.

The house is built with trusses. No one was cutting any rafters. And
the trusses are, dollars to donuts, held together with the gangnail
plates.

R

Some Guy wrote:

You could rent a lot of storage space or buy and build a small
storage shed for the same amount of money.


If you're a half decent carpenter and you throw enough 2x4's at it,
you'll probably end up with something stronger than you started with.

If you use 1/4 bolts with fender washers and (or) #12 or #14 wood
screws and pre-drill the holes (and not nail anything together) you'll
have something stronger than the existing framework.

I bet your existing wood is full of splits because of the hack job
that is usually done when cutting rafters and pounding over-sized
nails in.

Do yourself a favor and make sure each and every rafter space is
ventilated out to your soffit overhang. Don't stuff the insulation in
there - let it breath.

I have to add my professional opinion that this is very bad
advice. There is no way that I would give any advice on
modifying trusses where the work is going to be done by
someone I don't know, much less without even seeing the
situation in person.

Trusses are built with enough strength to hold up what they
are designed to carry and no more. Even storing stuff on them
is considered to be forbidden by the engineers that I use.
One of my PEs will not sign off on a job if there is decking
down on the trusses because he knows that something is going
to eventually be stored there and he will NOT let you leave
it. For him to sign off on the job, decking must be removed
except where it is necessary to access equipment.

The thought of modifying trusses is not a scary thought to me,
because I have done a lot of work that involved modification
and I have worked with a lot of engineers on what to do, and I
have 30 years of experience in construction. The thought of
advising someone else on doing it sends chills up and down my
spine.

Like the time I went to look at a job where the garage trusses
were failing and looked in the attic to see ENGINE BLOCKS
stored up there! I got the heck out of that place as fast as
I could.

--
Robert Allison
Rimshot, Inc.
Georgetown, TX

Colbyt wrote:

You are joking aren't you???????????
Most residential trusses are designed to hold up the roof and the
drywall. Attic junk not included. Floor load not included.

I guess that explains how I can load my roof with 120 bundles of
shingles and 5 guys (and that's in addition to the weight of the
existing shingles).

In a previous post Some Guy says...
I guess that explains how I can load my roof with 120 bundles of
shingles and 5 guys (and that's in addition to the weight of the
existing shingles).


Cut a few truss members and try it. That's what the OP was proposing.

Most roofers I've seen at least make an attempt to spread the load out
some. If you pile all 120 bundles in one place then a roof failure
would not be unexpected.

As for the 5 guys, I assume they are moving around and not sitting in a
bunch having a smoke. That makes them "short-term" load and wood is
pretty forgiving for that type of loading.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA

Some Guy wrote:
Colbyt wrote:

You are joking aren't you???????????
Most residential trusses are designed to hold up the roof and the
drywall. Attic junk not included. Floor load not included.

I guess that explains how I can load my roof with 120 bundles of
shingles and 5 guys (and that's in addition to the weight of the
existing shingles).

The truss is designed to be toploaded. If you put that same load on
the bottom chord of those same trusses they would fail.

Trusses are the most economical use of wood possible. Why do you feel
that they would build in all sorts of reserve strength (and give it
away)?

R

Even if the house plans provided an attic access, this does not mean the
trusses were designed to take an additional load above the ceiling. Its
implied by the attic access provided by the builder, but that doesn't mean
its true.

The chords tie the joist to the rafters in a typically angular fashion.
These are mutually supportive of both the joist and the rafter.

Trusses are designed to provide a minimum ceiling load as is. Especially
the exclusive 2X4 type. I wouldn't trust these without the chords in place.
A long run over a bedroom, living area etc is inviting disaster for storage
purposes in the attic. You cut the chords, and its an even worse situation.

Conventionally framed roofs with ceiling joists of adequate width meant for
storage is probably the only type one can safely store your stuff in the
attic. A few truss designers will design these if the ceiling load specs
are provided by the builder, but its not seen very often.

"Ken Moiarty" wrote in message
news:BYdwe.1819374$Xk.1125184@pd7tw3no...
Background: I'm trying to modify my attic a little bit in order to store
some things up there. Currently I'm busy fastening 3/4" plyboard over the
ceiling rafters (so objects to be stored won't crash thru the drywall
ceiling). However movement/activity up there is hampered by the fact that
the roof is supported by factory produced 2x4 trusses, as these are
composed
of many cross members that switch back-and-forth at oblique angles between
the upper and lower rafter sections of each truss. It would certainly
make
my attic storage efforts easier if some of these cross-members could
somehow
be removed out of the way (that is... in such a way as to not compromise
the
structural integrity of my roof, of course).

Therefore I'm requesting feedback on the following idea: 'Sistering'
(i.e.
reinforcing with) 2x6s to the topmost rafters, followed by removal of some
of the supporting cross-members of said trusses. Not being a carpenter or
structural engineer of any kind, I'm seeking informed comments/advice from
others before going further with this.

Thanks.

Ken

Some Guy ) said...
[talking about truss manufacturers]

Look. They churn out the same stuff day in and day out. They're not
going to have expensive computer software (and an even more expensive
engineer) on staff to basically twiddle his fingers. They don't
change their designs often enough to warrant that sort of cost.

This really has no idea what he is talking about.

While truss manufacturers will do some business "churning out the same
stuff" for subdivision builders, they also do a substantial amount of
work for custom built homes that are one-off projects.

As one who had to source out a truss manufacturer for our custom built
home with some rather unique roof components, they most certainly do
have this sort of capability.

Now, whether they would bother with looking into an alteration issue
as the original poster has, is a whole different question.


--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
-------------------------------------------------------------------------
NOTE: if replying by email, remove "remove." and ".invalid"

Colbyt ) said...

Most residential trusses are designed to hold up the roof and the drywall.

Attic junk not included. Floor load not included.

The trusses have some extra load capabilities. Afterall, they must
support workers up there moving around.

That said, many peoples' attic crap can easily exceed that capability
quite quickly!


--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
-------------------------------------------------------------------------
NOTE: if replying by email, remove "remove." and ".invalid"

The thought of modifying trusses is not a scary thought to me,
because I have done a lot of work that involved modification
and I have worked with a lot of engineers on what to do, and I
have 30 years of experience in construction. The thought of
advising someone else on doing it sends chills up and down my
spine.


Oh, come on, it's easy. The proper way to modify a truss for
load bearing is to run posts up between the existing trusses,
put beams across just over the top, and build a deck on the
new beams. No problem. You can ADD anything you
want, you just can't take anything out, and nothing that
you add is allowed to touch the existing system.

--Goedjn

Conventionally framed roofs with ceiling joists of adequate width meant for
storage is probably the only type one can safely store your stuff in the
attic. A few truss designers will design these if the ceiling load specs
are provided by the builder, but its not seen very often.

Huh? Virtually any truss manufacturer will design and supply
attic trusses for "bonus space". It's not exactly a complicated
or new problem. The problem is that if the truss *WASN'T* designed
for that, then it's almost certainly because the system can't
be easily modified to do it, else they WOULD have, when it went in.

And in someone else's post:


Attic junk not included. Floor load not included.

The trusses have some extra load capabilities. Afterall, they must
support workers up there moving around.

Work that through again... If the truss has, say 500# of excess
temporary support ability, because you need that for workers,
and you use that extra 500# for storage, what happens when the
workers show up?

Goedjn wrote:


The thought of modifying trusses is not a scary thought to me,
because I have done a lot of work that involved modification
and I have worked with a lot of engineers on what to do, and I
have 30 years of experience in construction. The thought of
advising someone else on doing it sends chills up and down my
spine.

Oh, come on, it's easy. The proper way to modify a truss for
load bearing is to run posts up between the existing trusses,
put beams across just over the top, and build a deck on the
new beams. No problem. You can ADD anything you
want, you just can't take anything out, and nothing that
you add is allowed to touch the existing system.

--Goedjn

Which doesn't solve OP's problem of limited access which is the whole
point of the thread...

"Some Guy" wrote in message ...
Colbyt wrote:

You are joking aren't you???????????
Most residential trusses are designed to hold up the roof and the
drywall. Attic junk not included. Floor load not included.

I guess that explains how I can load my roof with 120 bundles of
shingles and 5 guys (and that's in addition to the weight of the
existing shingles).

I didn't mention the design load for one nail over because I did not want
some fool trying to figure out how much attic junk that equaled.

It all comes to down to weight distribution and time.

Modify a truss or two the house most likely won't cave in. Over time you
may have some serious problems.

Your house, do as you wish. I won't help you do it by giving you risky
advice.

Colbyt

"Some Guy" wrote in message ...
wrote:

David,
If I gave a truss manufacturer a careful drawing of an existing
truss, a manufacturer could tell me what loads it could support?

A manufacturer will probably not even give you the time of day.

And I doubt they have a CAD system and/or expert that does finite
element analysis on the stuff they do make.

Better think again



Look. They churn out the same stuff day in and day out. They're not
going to have expensive computer software (and an even more expensive
engineer) on staff to basically twiddle his fingers.

Wrong again

They don't
change their designs often enough to warrant that sort of cost. Wood
trus engineering was worked out decades ago. It's not rocket science.

Wrong again


For liability issues no-one is going to look at your drawings and give
you a thumbs up or down.

"Some Guy" wrote in message ...
Colbyt wrote:

You are joking aren't you???????????
Most residential trusses are designed to hold up the roof and the
drywall. Attic junk not included. Floor load not included.

I guess that explains how I can load my roof with 120 bundles of
shingles and 5 guys (and that's in addition to the weight of the
existing shingles).


stretching my memory of wood structures class......
the allowable load for temp load was 133% of normal. Impact was 200%

you people are complete idiots for even trying to tell this person ways on
how to attempt this on his own. ive done framing for 15 years. just framing.
NEVER EVER EVER EVER EVER cut or modify a truss in ANY way without the
approval of a engineer or the truss co. ive fallen thro trusses because the
gangnails have given out (cheap pine) and i'm only 190 pounds. yea, lets
pile a bunch of junk up there

"Ken Moiarty" wrote in message
news:BYdwe.1819374$Xk.1125184@pd7tw3no...
Background: I'm trying to modify my attic a little bit in order to store
some things up there. Currently I'm busy fastening 3/4" plyboard over the
ceiling rafters (so objects to be stored won't crash thru the drywall
ceiling). However movement/activity up there is hampered by the fact that
the roof is supported by factory produced 2x4 trusses, as these are
composed
of many cross members that switch back-and-forth at oblique angles between
the upper and lower rafter sections of each truss. It would certainly
make
my attic storage efforts easier if some of these cross-members could
somehow
be removed out of the way (that is... in such a way as to not compromise
the
structural integrity of my roof, of course).

Therefore I'm requesting feedback on the following idea: 'Sistering'
(i.e.
reinforcing with) 2x6s to the topmost rafters, followed by removal of some
of the supporting cross-members of said trusses. Not being a carpenter or
structural engineer of any kind, I'm seeking informed comments/advice from
others before going further with this.

Thanks.

Ken

Why don't you just go in there with a sawzall and cut everything out of your
way.
That way, when the roof falls in, you can have it rebuilt with rafters and
then you will have lots of room.
And that will only cost about $20,000.00.
--
JerryD(upstateNY)

If you're a half decent carpenter and you throw enough 2x4's at it,
you'll probably end up with something stronger than you started with.

If you use 1/4 bolts with fender washers and (or) #12 or #14 wood
screws and pre-drill the holes (and not nail anything together) you'll
have something stronger than the existing framework.

I bet your existing wood is full of splits because of the hack job
that is usually done when cutting rafters and pounding over-sized
nails in.

Do yourself a favor and make sure each and every rafter space is
ventilated out to your soffit overhang. Don't stuff the insulation in
there - let it breath.

According to Some Guy :

For liability issues no-one is going to look at your drawings and give
you a thumbs up or down.

That's what civil engineers are _for_.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

I just saw this exact same thing on 'House Detective' on TLC. Someone
removed the center posts on a trusts an used 2x4 lag bolted in to the
remaining top and cross members.(yeah, I'm hooked those shows, but they
occasionally have really good info)

The result. The roof was fine but the floor was sagging. There was
about a 4" sag from the floor was originally(in the center)


Eitherway, knowing that a house is usually someones largest asset, do
you really want to compromise its value by cutting corners. Either
find an engineer or find a different space to store clutter.

c_kubie

In a previous post Chris Lewis says...
That's what civil engineers are _for_.


Sure. You just have to find one willing to do so.

As I said before, this is not cost effective. The price a homeowner is
willing to pay for services is not commensurate with the liability
exposure.

Are you willing to pay more than $1000 so you can store some stuff in
the attic. If you are, then I might consider doing the work.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA

Chris Lewis wrote:
According to Some Guy :


For liability issues no-one is going to look at your drawings and give
you a thumbs up or down.


That's what civil engineers are _for_.

The civil engineers that I use don't do structural.

--
Robert Allison
Rimshot, Inc.
Georgetown, TX

Thanks for all the helpful replies to my query. I absolutely had no idea
that using the attic to store things could pose a problem! But based on
what you people have told me here -plus the the regrettable realization from
my own observations that my house was built as cheaply and shoddily as its
builders could legally get away with- I now realize my attic CANNOT be used
for storage in any case.

Rant: For a home that sold for hundreds of thousands of dollars, you'd think
the builder could've been a little more liberal budgetwise and built the
house to higher spec.

Ken

In a previous post says...
This is the main reason I would NEVER build a house with trusses.


There is such a thing as an "attic truss". But, it must be specified at
the time of design and manufacture. Typically, the truss is designed
with an aisle way down the middle and the bottom chord is designed to
carny the weight of stuff stored in a typical attic.

The engineer or architect can specify a heavier than normal load on the
bottom chord. Obviously, the truss manufacturer will do what's typical
unless told to do otherwise. the spec building could specify an attic
truss, but that costs more. Most spec builders on not going to spend
the a few hundred extra dollars if they don't have to.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA

wrote:

This is the main reason I would NEVER build a house with trusses. The
older homes I have lived in all my life had stick framed roofs.
Normally 2x8's across the floor (above your ceiling) and they go from
the outer walls to the center support wall.

Most of the older homes that I've seen don't have such beefy floors.
Most of them have 2x6 ceiling joists or even 2x4s.

Then the roof is 2X6's
from the outer walls, and come together at the peak. Built that way,
you can make a real attic, build rooms up there and whatever.

Sure, if the home is built the way you say.

Trusses
save the expense of the larger dimension lumber, but are all wasted
space. They are fine for a barn or something where you would not need
an attic, but for a house they are just a big waste of space.

Trusses can be, and are, designed for all sorts of conditions and
loads. I frequently have to beef up or replace existing stick frame
structures when remodeling. If it wasn't designed for it, it has to be
modified. The only difference is that trusses are more complicated to
analyze and therefore modify.

Considering the high cost of trusses, I tend to wonder if they are
really worth the savings, because I tend to think the savings is
minimal.

Every tract home builder in the country disagrees with you. There are
many advantages - much longer spans possible eliminating the need for
interior support and concomitant foundation costs, faster roof framing,
weight savings, etc.

As for your situation, I can only say this. You cant just sister
the
roof joists, because the floor could drop (along with your ceiling
below) However, if you were to sister 2x8s across the floor, AND
2x6's on the roof, being sure both the 2x8's and 2x6s are resting on
the outer walls, and on the center support wall of the home, you could
probably get away with it.

If he's just looking to add storage capabilities (floor load), why does
he have to touch the roof? He could ignore the trusses and install
floor joists next to them, but if he doesn't have a center support
wall, he probably can't do that.

Look at the way an older home roof was
built, and duplicate that. But, if your trusses are 2x4s, you may not
be able to get your new wood onto the outer walls, unless you can cut
the angle and still have enough wood on the walls. I am not
suggesting you do this without having a professional engineer or
builder look at it, but it could possibly work. Your other option
would be to remove the entire roof and rebuild it using stick
construction, but I dont think you want to go that extreme.

Probably not.

As someone else said, trusses are not made to hold heavy loads, as a
floor. Those 2x4's are likely spliced right in the middle of your
rooms below, so even if you leave the trusses intact, I would still
add some at least 2x6's from outer walls to center walls and floor on
top of them.

You are advising that substantial loads be placed on walls that may not
be bearing walls...?

Of course you could move too....
Remember, many of the older stick built houses have lasted a hundred
years or more. These new houses built out of crap have a life
expectancy of about 30 years. So you might save a few bucks today,
but you will pay and pay and pay later.

Not sure where you got your life expectancy number from, but it's
_extremely_ pessimistic.

R

On Fri, 01 Jul 2005 08:02:06 GMT, "Ken Moiarty"
scribbled this interesting note:

Thanks for all the helpful replies to my query. I absolutely had no idea
that using the attic to store things could pose a problem! But based on
what you people have told me here -plus the the regrettable realization from
my own observations that my house was built as cheaply and shoddily as its
builders could legally get away with- I now realize my attic CANNOT be used
for storage in any case.

Rant: For a home that sold for hundreds of thousands of dollars, you'd think
the builder could've been a little more liberal budgetwise and built the
house to higher spec.

Ken


Really? Seems you fail to understand that as with any business these
days, accounting is what actually runs it, not the quality control
department!:~(


--
John Willis
(Remove the Primes before e-mailing me)

RicodJour wrote:

If he's just looking to add storage capabilities (floor load),
why does he have to touch the roof? He could ignore the trusses
and install floor joists next to them, but if he doesn't have a
center support wall, he probably can't do that.

Look what the original poster (OP) said:

"Currently I'm busy fastening 3/4" plyboard over the ceiling
rafters (so objects to be stored won't crash thru the drywall
ceiling)."

So we can assume that the rafters are strong enough to support someone
wiggling around putting plywood down?

3/4 plywood to tie the rafters together will certainly give some
additional strength to the load-bearing capacity.

Rant: For a home that sold for hundreds of thousands of dollars, you'd think
the builder could've been a little more liberal budgetwise and built the
house to higher spec.

Ken

What for? You bought it anyway...