"hr(bob) " writes:

On Feb 6, 9:42Â*pm, blueman wrote:
One of the 12" wide treads on our main staircase has an ~18" longitudinal
crack in it. As per an earlier thread, the consensus seems to be that
these treads are 150 yr old heart pine.

Here is a link to a pic:
Â* Â* Â*http://96.252.37.8:8080/public/1stFlrTread.jpg

I am not concerned about the visual look of the crack (if anyting it
adds "character") but the area under the crack is not well supported and
gives a bit when you put weight on it -- in fact, the absence of such
support may be the proximate cause of the crack. The crack has probably
been there for many years.

Since replacing the tread is not easily feasible given the old wood, I
would like to repair the tread.

Now removing the tread would not be easy since 2 balustrades are
toenailed into the other side of the tread and removing the entire
bannister and balustrades *seems* to me to be a big job.

So, I was thinking it might be easier for me to access the underside of
the tread from the alcove underneath the stairway by cutting through the
plaster and lathe on the underside of the stairway. My idea would be to
expose enough area so that I could slip another board underneath the
tread to span the crack and add support.

To secure the support, my thought was to cover it with glue (either
polyurethane or epoxy). Assuming that I won't be able to get good
clamping pressure from below, I would run some temporary small gauge screws
through the face of the tread to temporarily clamp the tread and support
board together. Alternatively, I could try to expose more of the stair
underside at the risk of creating more mess and a bigger plaster repair
job.

Before, I go cutting into the plaster and lathe, I wanted to get advice
on whether this is a good approach along with any additional advice or
pointers. Of course, I am open to *any* other better suggestions.

Thanks

I would glue the repair plate to the bottom of the cracked tread as
you suggested, and also secure it with screws just long enough to go
into the cracked tread, but not so long as to come thru the tread, and
leave the screws in permanently.
I was assuming that I would not have enough access room to screw in the
screws from below so that instead I would need to secure the backer
board by driving screws through the face of the tread from above. In
order to preserve the cosmetics of the tread, I was hoping that once the
glue set, I could remove the screws and at most have to add a wee bit of
woodfill to the holes left after removing the screws. My thinking was
that even if the underside of the tread is not completely smooth or flat
that epoxy or maybe construction adhesive would hold the boards together
securely after fully curing.

If the tread crack is 18 - 20 inches long in a tread that is probably
30 - 44 inches wide, I would work in as big a piece of wood as
possible and not skimp on the screws. You may want to predrill the
holes in both the repair plate and the stair tread to prevent any
further cracking/ I think regular wood glue should be ok, it dries so
strong that a different part of the wood will crack before the glues
section will crack.
I was assuming that the underside of the tread may be rough so that a
more space-filling glue like epoxy or construction adhesive might be
better.