I am using adjustable jack posts to level some sagging in my house - a
21' x 26' Cape. The greatest amount of sagging is about 1 ¾" to 2".
The house sags in three distinct areas:

1) Toward the center, along the center beam (originally on three
lally columns)
2) Around the stairs (north side of the center beam [NCB])
3) Along the wall bisecting the house, roughly in half, and
providing (south of the center beam [SCB]) the entry to the kitchen

Gradual extension of the jack post screws (placed under the center
beam and additional plates along various strategic points, SCB, shows
good results with about 3/8" to ½" already regained. This is where the
inexcusable under-design (1947 construction) of the house becomes
evident. The wall which bisects the house north-south and provides the
entry into the kitchen does not rest on a joist. It is instead placed
right smack in the middle, between two joists (7" joists, placed 16"
OC). This wall happens to carry the load for the finished second floor
and is supported by ¾" subfloring only!!!

As the center beam and the joists are beginning to move back into
proper level, the boards under the kitchen entryway wall are beginning
to bow even more. I need to add that this particular area was already
sunk lower than the rest of the house, for obvious reasons. The house
contained a sag within the sag as the main floor came down due to the
settlement of the lally columns, and the kitchen entryway wall itself
then also sagged somewhat (1/2") below the floor level, more or less.

To fix this condition, I plan to add a span of a 5" x 7" beam running
between the joists and directly under the offending wall. Two jack
posts will be placed under the added beam, ensuring that I am raising
the wall in question, along with the rest of the structure.

Once the add-on beam is in place and the leveling is complete, I plan
on adding perpendicular 2"x10" plates securing the add-on beam to both
adjoining existing joists. The permanent supporting new lally columns,
on concrete footings, will go under the new perpendicular plates,
distributing the load along three members.

If you are still reading, here are my questions:

Can I fabricate the 5"x7" beam by combining ¾" plywood with 2x7"
boards? I've heard of this done and it seems to make sense, but I am
not sure if this is a better method than a solid beam. I can see both
sides of the argument: a solid beam can deform in unison due to
internal flaws, etc. OTOH it is a solid piece(!) while a composite
might offer more rigidity, if done correctly, but more components are
involved.

As far as composite beams go - what is the correct method of producing
them? Liquid nails, fasteners, wood glue, clamps?

Anyway, I would appreciate any comments and suggestions you can make.
I am not a professional builder, by trade - as you can tell - and my
methods and ideas might be completely off the mark with the above. If
you tell me I am nuts, I won't take it the wrong way. Thank you for
bearing with it [NPI]!


Michael

You can do any of those ways, but be sure your jacks have a good
foundation and you only turn them one turn a day or less, or your walls
will crack bad.. Take a few weeks to go up an inch

(MS) wrote in message ...
I am using adjustable jack posts to level some sagging in my house - a
21' x 26' Cape. The greatest amount of sagging is about 1 ¾" to 2".
The house sags in three distinct areas:

1) Toward the center, along the center beam (originally on three
lally columns)
2) Around the stairs (north side of the center beam [NCB])
3) Along the wall bisecting the house, roughly in half, and
providing (south of the center beam [SCB]) the entry to the kitchen

Gradual extension of the jack post screws (placed under the center
beam and additional plates along various strategic points, SCB, shows
good results with about 3/8" to ½" already regained. This is where the
inexcusable under-design (1947 construction) of the house becomes
evident. The wall which bisects the house north-south and provides the
entry into the kitchen does not rest on a joist. It is instead placed
right smack in the middle, between two joists (7" joists, placed 16"
OC). This wall happens to carry the load for the finished second floor
and is supported by ¾" subfloring only!!!

As the center beam and the joists are beginning to move back into
proper level, the boards under the kitchen entryway wall are beginning
to bow even more. I need to add that this particular area was already
sunk lower than the rest of the house, for obvious reasons. The house
contained a sag within the sag as the main floor came down due to the
settlement of the lally columns, and the kitchen entryway wall itself
then also sagged somewhat (1/2") below the floor level, more or less.

To fix this condition, I plan to add a span of a 5" x 7" beam running
between the joists and directly under the offending wall. Two jack
posts will be placed under the added beam, ensuring that I am raising
the wall in question, along with the rest of the structure.

Once the add-on beam is in place and the leveling is complete, I plan
on adding perpendicular 2"x10" plates securing the add-on beam to both
adjoining existing joists. The permanent supporting new lally columns,
on concrete footings, will go under the new perpendicular plates,
distributing the load along three members.

If you are still reading, here are my questions:

Can I fabricate the 5"x7" beam by combining ¾" plywood with 2x7"
boards? I've heard of this done and it seems to make sense, but I am
not sure if this is a better method than a solid beam. I can see both
sides of the argument: a solid beam can deform in unison due to
internal flaws, etc. OTOH it is a solid piece(!) while a composite
might offer more rigidity, if done correctly, but more components are
involved.

As far as composite beams go - what is the correct method of producing
them? Liquid nails, fasteners, wood glue, clamps?

Anyway, I would appreciate any comments and suggestions you can make.
I am not a professional builder, by trade - as you can tell - and my
methods and ideas might be completely off the mark with the above. If
you tell me I am nuts, I won't take it the wrong way. Thank you for
bearing with it [NPI]!


Michael


I pretty much followed you. Not sure on one point but it is a biggie.
Do not continue jacking on your existing set-up -until- you have
installed the new beam and brought that portion up to the same level
as the othe ones. You are dangerously close to having the center wall
punch right through the floor.

As to your question about the beam. A laminated beam 2x8 with ply
sandwiched between will be stronger than a 1 piece and far more likely
to be straight than one solid wood beam. My method is either
resorcinol glue or liquid nails. The glue probably gives a better
bond. Simple nailing is sufficient, you don't need to clamp it. When
assembling sight down the 2x and place the crowns opposite each other
then begin nailing from one end drawing the loose ends into line. The
closer you get to the end, the harder it will be to draw the ends in
line. This is where you might need clamps. If so, leavit it/them in
place until the glue dries. This results in a straight beam if the
bow in the 2x's are approximately equal. You will need to be careful
in that respect when selecting the lumber.

Harry K

(MS) wrote in message ...
I am using adjustable jack posts to level some sagging in my house - a
21' x 26' Cape. The greatest amount of sagging is about 1 ¾" to 2".
The house sags in three distinct areas:

1) Toward the center, along the center beam (originally on three
lally columns)
2) Around the stairs (north side of the center beam [NCB])
3) Along the wall bisecting the house, roughly in half, and
providing (south of the center beam [SCB]) the entry to the kitchen

If I understand you correctly, you are planning to raise a sagging
wall sitting between two parallel joists by jacking at two ends of a
short beam placed under the wall perpendicular to it the middle of the
wall span.

I'd jack the wall up at two locations, one third span. To do this you
need for jacks. On second thought, if you get four jacks, it is more
effective jacking the wall directly at four locations under the wall.

I am using adjustable jack posts to level some sagging in my house

Before you get into real trouble, lets review one of the basic laws of physics:
"For every action there is an equal and opposite reaction".
So what kind of footing do your jack posts bear against? Seems to me that the
first thing you do in any project like this is to prepare an adequate
foundation to carry the weight of the structure. If unsure, getting some xpert
help will ensure your success. Good luck.

Joe

Thank you for your comments everyone!

Harry, you are absolutely right, the wall that sits supported by the
subfloor (and aligned in parallel to the joists on either side) will
soon punch through the subfloor, if I continue jacking those joists
up. I've actually magnified the condition (at first) by placing two
screw jacks (pushing up against a 2x10 plate, mounted in perpendicular
to the joists) under that general area. These two screw jacks are in
addition to the four I placed under the main beam.

With pressure first applied to the center beam only, the center
portion of the house began to come up, but the offending wall area
stayed dipped (to the same degree as before), hence the additional two
jacks and the 2x10 under that wall.

Once the last two jacks began coming up, the subfloor sag became
pronounced and I stopped turning those jacks.

Today I've brought the center beam jacks up by one turn and the sag
under the offending wall subdued, but did not disappear. The reason
for it, as I understand it, is that the two auxiliary jacks (those
pushing up under the added 2x10) are extended further than those that
are under the center beam. Makes sense, since it was a lot easier to
extend the auxiliary jacks, acting on a limited set of joists (to the
left, right and under the offending wall) than it was to turn the
jacks under the main beam, supporting the center ends of all joists in
the house.

OK, now for the latest strategy: I have to remove the sheetrock and
the heating ducts that are in the way between the joists requiring an
additional beam. I am now wondering - with clear access to the work
area - whether or not it might be better to install a full length
composite joist (it will run directly under the unsupported wall),
instead of merely a section?

I can see clear access where the end of the new joist should rest on
the foundation side. The center beam side is a bit more involved as
the end of a joist from the other side of the house protrudes over the
center beam, by about 10" and is directly in line with where I want
the new additional joist to rest.

My idea to get around this constraint is to make a composite - three
layer - beam. Each layer will have to be a 2x7 (as are the existing
joists) with the full length, outside layers sitting on the center
beam and placed on either side of the joist extension from the other
side of the house. The middle layer of the new composite beam will
need to be shorter of course.

I know that this operation is akin to sistering of joists, except that
this particular exercise, if possible, in essence requires assembling
the composite joist exactly in its final position.

My final epiphany is that I should leave this particular part of the
project to a professional builder.

So, in summary, please dissuade me from wanting to install a full
length beam and I'll go with the free floating, jack post-supported
partial composite beam. In the alternative, I'll be asking for
recommendation on which Boston area builder to seek out.

Michael

On 19 Mar 2004 04:19:44 -0800, (Harry K)
wrote:


I pretty much followed you. Not sure on one point but it is a biggie.
Do not continue jacking on your existing set-up -until- you have
installed the new beam and brought that portion up to the same level
as the othe ones. You are dangerously close to having the center wall
punch right through the floor.

As to your question about the beam. A laminated beam 2x8 with ply
sandwiched between will be stronger than a 1 piece and far more likely
to be straight than one solid wood beam. My method is either
resorcinol glue or liquid nails. The glue probably gives a better
bond. Simple nailing is sufficient, you don't need to clamp it. When
assembling sight down the 2x and place the crowns opposite each other
then begin nailing from one end drawing the loose ends into line. The
closer you get to the end, the harder it will be to draw the ends in
line. This is where you might need clamps. If so, leavit it/them in
place until the glue dries. This results in a straight beam if the
bow in the 2x's are approximately equal. You will need to be careful
in that respect when selecting the lumber.

Harry K

get a pro out to advise you on your problem- situation before you Blow
it...

Thank you for the advice. I am looking for a contractor right now...



On Fri, 19 Mar 2004 22:18:35 -0600 (CST), (m
Ransley) wrote:

get a pro out to advise you on your problem- situation before you Blow
it...