David Alexander wrote in
:

On Sat, 06 Mar 2004 21:57:27 GMT, "James Lee Johnson"
wrote:


"David Alexander" wrote:
I have some enclosed stairs 39" wide with only two stringers
...
I plan to glue and screw two layers of 3/4" plywood for the treads.
This will give me roughly the same height as the old 2x's. The
front edge of the tread will sit on top of the riser below for
support. Will that be sturdy enough considering the span and lack of
center stringer? I'm thinking that I need to support the back edge
of the treads as well and I've had a couple wild ideas for how to do
that.
...

I have been letting your question "stew" a little while before
answering.

Cut your risers and treads.

Laminate the treads and like you are planning to do. I would probably
use construction adhesive for the glue. Some screws up through the
bottom to pull it together while the glue dries.

For the risers use some of that 1 1/4 inch ply for flooring. You are
going to need some strength in the risers to because they are what is
going to support the weight on the stairs and transfer it to the
stringers.

I might think about re-inforcing the stringers too by running a 2x?
along the lower inside edge of the string. Glue and screw that baby on.

Then make up a jig to hold the riser and tread in the correct position.
What you want to do is firmly attach the back of the tread to the front
of the riser that is going above it. The week point is not going to be
the front of the tread. Like you said the front of the tread sits on
the riser and will provide support.

What I would do is build the tread and riser together then put it on the
stair. This way you can STRONGLY attach the tread to the riser behind
it. You can use biscuits if you want but use plenty of glue. What I
would do is from the back of the riser I would run 3 1/4x4" lag bolts
through the riser and into the back of the tread. Space them evenly
across the tread at about 12 inches from each side and then one in the
center. Pre drill all the holes and you could even put the stairs
together after they are on the stringers.

Use lots of construction adhesive. It doesn't expand or shrink. It
will fill gaps and it is pretty strong stuff.

Last year I built a set of stairs for a friend. Boy those suckers are
strong!