I need to install a new header to enlarge a window (in a load bearing wall).
I was always under the impressing that kiln dried lumber, instead of green
was the only way to go when altering existing construction, to avoid the
As far as I can discover, only green lumber is available in New Jersey for
larger than 2 x 4's.
I am particularly concerned that the ceiling, which is supported by this
will crack over time, as the new header shrinks.
Am I worrying about this unnecessarily, or is there a technique of
that avoids the problems of shrinkage?
Window header stock (beams) doesn't come kiln dried. At least I've never
seen it come that way. Your option is to use 2x (insert width here) kiln
dried stock and nail them together using 1/2" plywood in between to fill the
width. Or buy the thick stock beam you need which is what I would do if I
was framing it.
SH - The "general contracting" woodworker
Around here (Pacific NW) I can get kiln dried up to 2x8's or so, but 2x6 is
about the largest size that's easy to find.
In any case, I used green 2x10's for our door and window headers and
haven't noticed any shrinkage problems (no drywall cracks).
That assumes a 2x4 wall. In our house (2x6 walls), I used two 2x10's, one
on the outside of the wall, and one on the inside of the wall. Then I
filled the space in between with fiberglass insulation. Our largest span
was 5' and only had the roof load above, so this worked very well. Of
course, the success depends on the span and the load it is carrying.
A solid beam weighs more, will probably shrink more, and doesn't provide
much insulating value. Also, since this sounds like a remodeling situation,
I would think it would be harder to get a solid beam in place than a couple
I never seem to have shrinkage problems with wood that reflects through
the sheetrock as a crack. I use off the rack 2X material, and build a
sandwich beam by laminating the 2xs on both sides of 1/2 inch plywood
and plenty of glue.
Most long term cracks I have seen (that weren't caused by movement)
when we pull out old walls are from 1) the header being sized to
minimum structural requirements instead of one size over, 2) the
headers didn't have the 2xs crowned properly, leading to the worst
offender, 3) headers were not assmebled properly so that they sat dead
flat in the framing causing them to move over time.
If you are worried about what size wood to use, your library or B&N
will have plenty of books with span tables in them detailing nominal
Use plenty of nails and glue, build your header correctly and you won't
have a problem with regular yellow pine. Unless specified differently,
that's all we use.
A couple of more thoughts.
Don't mistake "green lumber" for kiln dried. Some is, some isn't. If
you decide to go with this option, it will proudly reflect in the price
that it is kiln dried as well as be stamped accordingly.
On other thing, when assembling your beam, make sure your nails
penetrate both pieces of 2x completely. If you are using pneumatic
tools, use 10d or 12d. If you are hand nailing, use 12d or 16d and
bend over the points. Enough nails can keep the shear stress on the
beam down to almost nothing, and are an important integral part of this
live load component.
Thank you all for your replies. If it were longer, I would go the
wood route, but its only a couple of 2 x 6's.
I did not think of the plywood being a stabalizing factor, but of course it
And I did not think of gluing it all togeather.
Glue, plywood and long nails, clinched over. I feel much better about this
We must be spoiled on the West Coast of Canada... all I can see in our
lumber yards is kiln dried lumber.... miles and miles of it. Right up to
and including 2 x 12. Of course we have pressure treated too.... always
used where wood touches concrete (with a layer of closed cell insulation
added just to be sure.)
How can you build anything with green lumber without it twisting like crazy
when it dries out?
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