I am designing a new house. We will be using 12" engineered joists
with relatively short spans. The deflections on these alone calculate
to about 1/500 of the span. We will be using glued and screwed 3/4" ply
for the subfloor on top of that. I haven calculated that deflection,
but its got to be real small. Normally, the 3/4" hardwood floor would
run perpendicular to the joists. However, to do that would require a
framing direction that is much more expensive. Given that the floor is
so stiff, can we run the flooring parallel to the joists - or is that a
"never" rule?
Len
Len wrote:>I am designing a new house. We will be using 12" engineered
joists
>with relatively short spans. The deflections on these alone calculate
>to about 1/500 of the span. We will be using glued and screwed 3/4" ply
>for the subfloor on top of that. I haven calculated that deflection,
>but its got to be real small. Normally, the 3/4" hardwood floor would
>run perpendicular to the joists. However, to do that would require a
>framing direction that is much more expensive. Given that the floor is
>so stiff, can we run the flooring parallel to the joists - or is that a
> "never" rule?
>
Len
When running the ply perpendicular to
the joists, why not? Tom
Work at your leisure!
The builder is trying to save a joist every 8 ft.
Cheap builder. Panel stiffness is the cube (power of 3)
of the span. (19.2^3)/(18^3)= 1.21
21 % more deflection. Good for creaky floors.
"Jim Behning" <[email protected]> wrote in message
news:[email protected]...
> Well that makes too much sense. Almost 7 years and I never thought
> enough to figure that out.
>
> Thanks.
>
> "Tyke" <[email protected]> wrote:
>
>>I think the 19.2 inch centres is the whole number to allow increments of
>>exactly 8 ft for the subfloor. 5 x 19.2 = 96 in = 8 ft but still have a
>>wider spacing than 16in. I expect 24in spacing would result in the
>>subfloor
>>needing to be increased in thickness too much.
>>
>>Dave Paine
>>
>>"Jim Behning" <[email protected]> wrote in message
>>news:[email protected]...
>>> I am confused. I have seen hardwood flooring running 2 different
>>> directions in a house depending on where the joist ran in a house. Is
>>> there a reson why you want the flooring to run a certain direction?
>>>
>>> Plywood does all kinds of crazy bowing and dipping. When you nail into
>>> those valleys it may not be pretty. The flooring that runs
>>> perpendicular to the joists is usually spanning a joist or 2 or 3. Of
>>> course that depends on the wood you install. My house has engineered
>>> joists on 19.2 inch centers. How they came up with that number in
>>> Atalnta Ga. I'll never know.
>>>
>>>
>>> Leonard Lopez <[email protected]> wrote:
>>>
>>> >I am designing a new house. We will be using 12" engineered joists
>>> >with relatively short spans. The deflections on these alone calculate
>>> >to about 1/500 of the span. We will be using glued and screwed 3/4"
>>> >ply
>>> >for the subfloor on top of that. I haven calculated that deflection,
>>> >but its got to be real small. Normally, the 3/4" hardwood floor would
>>> >run perpendicular to the joists. However, to do that would require a
>>> >framing direction that is much more expensive. Given that the floor is
>>> >so stiff, can we run the flooring parallel to the joists - or is that a
>>> > "never" rule?
>>> >
>>> >Len
>>>
>>
>
I think the 19.2 inch centres is the whole number to allow increments of
exactly 8 ft for the subfloor. 5 x 19.2 = 96 in = 8 ft but still have a
wider spacing than 16in. I expect 24in spacing would result in the subfloor
needing to be increased in thickness too much.
Dave Paine
"Jim Behning" <[email protected]> wrote in message
news:[email protected]...
> I am confused. I have seen hardwood flooring running 2 different
> directions in a house depending on where the joist ran in a house. Is
> there a reson why you want the flooring to run a certain direction?
>
> Plywood does all kinds of crazy bowing and dipping. When you nail into
> those valleys it may not be pretty. The flooring that runs
> perpendicular to the joists is usually spanning a joist or 2 or 3. Of
> course that depends on the wood you install. My house has engineered
> joists on 19.2 inch centers. How they came up with that number in
> Atalnta Ga. I'll never know.
>
>
> Leonard Lopez <[email protected]> wrote:
>
> >I am designing a new house. We will be using 12" engineered joists
> >with relatively short spans. The deflections on these alone calculate
> >to about 1/500 of the span. We will be using glued and screwed 3/4" ply
> >for the subfloor on top of that. I haven calculated that deflection,
> >but its got to be real small. Normally, the 3/4" hardwood floor would
> >run perpendicular to the joists. However, to do that would require a
> >framing direction that is much more expensive. Given that the floor is
> >so stiff, can we run the flooring parallel to the joists - or is that a
> > "never" rule?
> >
> >Len
>
Well that makes too much sense. Almost 7 years and I never thought
enough to figure that out.
Thanks.
"Tyke" <[email protected]> wrote:
>I think the 19.2 inch centres is the whole number to allow increments of
>exactly 8 ft for the subfloor. 5 x 19.2 = 96 in = 8 ft but still have a
>wider spacing than 16in. I expect 24in spacing would result in the subfloor
>needing to be increased in thickness too much.
>
>Dave Paine
>
>"Jim Behning" <[email protected]> wrote in message
>news:[email protected]...
>> I am confused. I have seen hardwood flooring running 2 different
>> directions in a house depending on where the joist ran in a house. Is
>> there a reson why you want the flooring to run a certain direction?
>>
>> Plywood does all kinds of crazy bowing and dipping. When you nail into
>> those valleys it may not be pretty. The flooring that runs
>> perpendicular to the joists is usually spanning a joist or 2 or 3. Of
>> course that depends on the wood you install. My house has engineered
>> joists on 19.2 inch centers. How they came up with that number in
>> Atalnta Ga. I'll never know.
>>
>>
>> Leonard Lopez <[email protected]> wrote:
>>
>> >I am designing a new house. We will be using 12" engineered joists
>> >with relatively short spans. The deflections on these alone calculate
>> >to about 1/500 of the span. We will be using glued and screwed 3/4" ply
>> >for the subfloor on top of that. I haven calculated that deflection,
>> >but its got to be real small. Normally, the 3/4" hardwood floor would
>> >run perpendicular to the joists. However, to do that would require a
>> >framing direction that is much more expensive. Given that the floor is
>> >so stiff, can we run the flooring parallel to the joists - or is that a
>> > "never" rule?
>> >
>> >Len
>>
>
In article <[email protected]>,
ddinc <[email protected]> wrote:
>The builder is trying to save a joist every 8 ft.
>Cheap builder. Panel stiffness is the cube (power of 3)
>of the span. (19.2^3)/(18^3)= 1.21
With 'standard' spacig being 16", not 18", it's even worse
19.2^3 / 16^3 = 1.728
Ouch!
>21 % more deflection. Good for creaky floors.
>
>"Jim Behning" <[email protected]> wrote in message
>news:[email protected]...
>> Well that makes too much sense. Almost 7 years and I never thought
>> enough to figure that out.
>>
>> Thanks.
>>
>> "Tyke" <[email protected]> wrote:
>>
>>>I think the 19.2 inch centres is the whole number to allow increments of
>>>exactly 8 ft for the subfloor. 5 x 19.2 = 96 in = 8 ft but still have a
>>>wider spacing than 16in. I expect 24in spacing would result in the
>>>subfloor
>>>needing to be increased in thickness too much.
>>>
>>>Dave Paine
>>>
>>>"Jim Behning" <[email protected]> wrote in message
>>>news:[email protected]...
>>>> I am confused. I have seen hardwood flooring running 2 different
>>>> directions in a house depending on where the joist ran in a house. Is
>>>> there a reson why you want the flooring to run a certain direction?
>>>>
>>>> Plywood does all kinds of crazy bowing and dipping. When you nail into
>>>> those valleys it may not be pretty. The flooring that runs
>>>> perpendicular to the joists is usually spanning a joist or 2 or 3. Of
>>>> course that depends on the wood you install. My house has engineered
>>>> joists on 19.2 inch centers. How they came up with that number in
>>>> Atalnta Ga. I'll never know.
>>>>
>>>>
>>>> Leonard Lopez <[email protected]> wrote:
>>>>
>>>> >I am designing a new house. We will be using 12" engineered joists
>>>> >with relatively short spans. The deflections on these alone calculate
>>>> >to about 1/500 of the span. We will be using glued and screwed 3/4"
>>>> >ply
>>>> >for the subfloor on top of that. I haven calculated that deflection,
>>>> >but its got to be real small. Normally, the 3/4" hardwood floor would
>>>> >run perpendicular to the joists. However, to do that would require a
>>>> >framing direction that is much more expensive. Given that the floor is
>>>> >so stiff, can we run the flooring parallel to the joists - or is that a
>>>> > "never" rule?
>>>> >
>>>> >Len
>>>>
>>>
>>
>
>
On Wed, 22 Sep 2004 03:11:11 GMT, Jim Behning
<[email protected]> wrote:
>The floors do not creak. I have been living in the house for nearly
>seven years and the floors are silent. Just like the brand name on the
>14" joists.
Are those engineered joists? It sounds like they are.
Engineered and metal products can carry different usage specs as 2x
joists.
Barry
I am confused. I have seen hardwood flooring running 2 different
directions in a house depending on where the joist ran in a house. Is
there a reson why you want the flooring to run a certain direction?
Plywood does all kinds of crazy bowing and dipping. When you nail into
those valleys it may not be pretty. The flooring that runs
perpendicular to the joists is usually spanning a joist or 2 or 3. Of
course that depends on the wood you install. My house has engineered
joists on 19.2 inch centers. How they came up with that number in
Atalnta Ga. I'll never know.
Leonard Lopez <[email protected]> wrote:
>I am designing a new house. We will be using 12" engineered joists
>with relatively short spans. The deflections on these alone calculate
>to about 1/500 of the span. We will be using glued and screwed 3/4" ply
>for the subfloor on top of that. I haven calculated that deflection,
>but its got to be real small. Normally, the 3/4" hardwood floor would
>run perpendicular to the joists. However, to do that would require a
>framing direction that is much more expensive. Given that the floor is
>so stiff, can we run the flooring parallel to the joists - or is that a
> "never" rule?
>
>Len
The floors do not creak. I have been living in the house for nearly
seven years and the floors are silent. Just like the brand name on the
14" joists. The builder did not give a rats butt about cost. I wrote
all the checks for materials and labor. The floor joist size and
spacing was based on some computer program the joist vendor made. I
guess next time you come over for a visit you can stomp aroung the
house and tell me which areas have joists 19.2 on center and which has
joists 16" on center. ;-)
"ddinc" <[email protected]> wrote:
>The builder is trying to save a joist every 8 ft.
>Cheap builder. Panel stiffness is the cube (power of 3)
>of the span. (19.2^3)/(18^3)= 1.21
>
>21 % more deflection. Good for creaky floors.
>
>"Jim Behning" <[email protected]> wrote in message
>news:[email protected]...
>> Well that makes too much sense. Almost 7 years and I never thought
>> enough to figure that out.
>>
>> Thanks.
>>
>> "Tyke" <[email protected]> wrote:
>>
>>>I think the 19.2 inch centres is the whole number to allow increments of
>>>exactly 8 ft for the subfloor. 5 x 19.2 = 96 in = 8 ft but still have a
>>>wider spacing than 16in. I expect 24in spacing would result in the
>>>subfloor
>>>needing to be increased in thickness too much.
>>>
>>>Dave Paine
>>>
>>>"Jim Behning" <[email protected]> wrote in message
>>>news:[email protected]...
>>>> I am confused. I have seen hardwood flooring running 2 different
>>>> directions in a house depending on where the joist ran in a house. Is
>>>> there a reson why you want the flooring to run a certain direction?
>>>>
>>>> Plywood does all kinds of crazy bowing and dipping. When you nail into
>>>> those valleys it may not be pretty. The flooring that runs
>>>> perpendicular to the joists is usually spanning a joist or 2 or 3. Of
>>>> course that depends on the wood you install. My house has engineered
>>>> joists on 19.2 inch centers. How they came up with that number in
>>>> Atalnta Ga. I'll never know.
>>>>
>>>>
>>>> Leonard Lopez <[email protected]> wrote:
>>>>
>>>> >I am designing a new house. We will be using 12" engineered joists
>>>> >with relatively short spans. The deflections on these alone calculate
>>>> >to about 1/500 of the span. We will be using glued and screwed 3/4"
>>>> >ply
>>>> >for the subfloor on top of that. I haven calculated that deflection,
>>>> >but its got to be real small. Normally, the 3/4" hardwood floor would
>>>> >run perpendicular to the joists. However, to do that would require a
>>>> >framing direction that is much more expensive. Given that the floor is
>>>> >so stiff, can we run the flooring parallel to the joists - or is that a
>>>> > "never" rule?
>>>> >
>>>> >Len
>>>>
>>>
>>
>
Well yes. I would have screamed all kinds of stuff if they tried to
install 2x lumber in such an odd spacing.
Ba r r y <[email protected]> wrote:
>On Wed, 22 Sep 2004 03:11:11 GMT, Jim Behning
><[email protected]> wrote:
>
>>The floors do not creak. I have been living in the house for nearly
>>seven years and the floors are silent. Just like the brand name on the
>>14" joists.
>
>Are those engineered joists? It sounds like they are.
>
>Engineered and metal products can carry different usage specs as 2x
>joists.
>
>Barry