(I posted this in alt.home.repair but I thought I'd ask the folks in
here too since I know a lot of you do this kind of work.)

I am about to rebuild some stairs and I'd like some feedback on
whether my ideas for the treads are going to work or not.

I have some enclosed stairs 39" wide with only two stringers on the
outside edges. Adding a middle stringer would mean some major
construction due to the way things are laid out. Currently, the
treads are 2x lumber with carpet. Naturally, removing the carpet
reveals that the 2x's are not flat, or straight, or in any way
suitable for my new treads. I'd like to use plywood to make new
treads for stability and flatness.

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.

One idea is to have each riser drop below the back of the tread and
cut a dado in the riser that the tread can slip into at the back.

Another idea is to use a double row of biscuits to join the back of
the tread to the face of the riser.

I've also thought about modifying the dado idea and just gluing on a
ledge that the tread sits on rather than milling a dado. The face to
face glue up for the ledge should be very strong.

Then there's the idea of mounting "joists" across the stairwell just
below each tread.

The question is, do I really need to do this or will the 1-1/2" of
plywood be stiff enough over time given that the front edge will be
supported?


Here's a picture I threw together for the first section of stair that
I'm redoing.

http://www.pobox.com/~DaveA/treads.jpg

It's only a 16" stepdown with two treads. This one I could easily
rebuild with all the stringers I want but I'd like to use it as a
model for my main stairs so I'll have my process down when I get
there.

"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.
....

David, I agree that 30+ inches is a large span for a tread. Do the 2x
treads feel bouncy now? I suggest using a "lock joint" made by extending
the TOP tread layer about 1/4 inch or more into a 3/4" wide dado in the
riser. This avoids having to make the riser drop below the tread bottom and
provides lots of glue surface. After all the glue dries the 1 1/2 in tread
and lock joint will be strong and stiff. Another alternative is to cut back
the LOWER tread layer and glue and nail in a rail that is, say 3/4 by 3".
This is similar to your idea of adding a "joist" under each tread. This
second alternative has the advantage of not involving the riser in the
tread stiffening system. You could even layer the rail by face gluing a
second 3/4 by 2 1/4" piece to it, or by using a piece of lumber and cutting
a rabbet along the top edge. This would provide a double step lock joint
giving even more glue surface. In every design I am assuming your cuts will
be straight and smooth so you can use woodworker's glue to provide strong
bonds. I think your idea of using biscuits will work fine also, although I
believe a double row would be overkill.

In conclusion, I would avoid notching the two existing stringers to
accomodate extended risers or tread rails or tread joists unless those
stringers are MUCH beefier than normal. Such notches create a stress point.
If you extend the risers down, notch the risers so the extended part fits
BETWEEN the stringers. Like wise, any tread rails or joist supports should
fit between the stringers. It is my belief that your laminated 1 1/2"
treads will be plenty strong, but without any middle stringers, they will
have an annoying bounce and a disconcerting tendancy to bend under load. I
think your "wild" ideas are on the right track, er I mean the right-angle,
but are over engineered. The main goal is to stiffen the tread. You could
probably get by with just a butt joint between the tread and riser if it is
true and square and glued up well.

I like your picture. What did you use to create it? Here is a reference on
treads, risers, and nosings you should look at before you finalize your
design:
http://www.access-board.gov/adaag/html/adaag.htm#4.9

I hope these suggestions help. If any of it is unclear, request a better
description. Let me know how the project goes.

jj

On Sat, 06 Mar 2004 11:27:37 -0700, David Alexander
wrote:

(I posted this in alt.home.repair but I thought I'd ask the folks in
here too since I know a lot of you do this kind of work.)

I am about to rebuild some stairs and I'd like some feedback on
whether my ideas for the treads are going to work or not.

I have some enclosed stairs 39" wide with only two stringers on the
outside edges. Adding a middle stringer would mean some major
construction due to the way things are laid out. Currently, the
treads are 2x lumber with carpet. Naturally, removing the carpet
reveals that the 2x's are not flat, or straight, or in any way
suitable for my new treads. I'd like to use plywood to make new
treads for stability and flatness.

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.

One idea is to have each riser drop below the back of the tread and
cut a dado in the riser that the tread can slip into at the back.

Another idea is to use a double row of biscuits to join the back of
the tread to the face of the riser.

I've also thought about modifying the dado idea and just gluing on a
ledge that the tread sits on rather than milling a dado. The face to
face glue up for the ledge should be very strong.

Then there's the idea of mounting "joists" across the stairwell just
below each tread.

The question is, do I really need to do this or will the 1-1/2" of
plywood be stiff enough over time given that the front edge will be
supported?


Here's a picture I threw together for the first section of stair that
I'm redoing.

http://www.pobox.com/~DaveA/treads.jpg

It's only a 16" stepdown with two treads. This one I could easily
rebuild with all the stringers I want but I'd like to use it as a
model for my main stairs so I'll have my process down when I get
there.

if you decide not to suport the middle they will be weak. you realy
should add a middle stringer. a dado on the riser may work. 2 layers
of plywood would be strong enough but in all of these fixes you are
trying to eliminate movement when the steps are walked on. movement
under stress will produce squeeks.i would use standard stair tread
wheather it be oak or SYP is up to you.oak treads are sturdy but
rather expensive. subfloor adhesive or liquid nails should be used.
dont be affraid to put the glue in. the more the better..again the
best way would be to cut in a middle stringer. it isnt that difficult
to do. line each side with a 2x4 for added strength. skeez

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.
...
snippage

I hope these suggestions help. If any of it is unclear, request a better
description. Let me know how the project goes.


Thank you James and, um, "skeezics" for the feedback. Both were very
helpful. I'm building the smaller section of stairs tomorrow and will
probably go with biscuit joining the rear of the tread to the face of
the riser. FWIW, it's actually about a 35" span between the
stringers.

To answer a few questions... the current 2x treads are solid and don't
feel bouncy at all. Then again, they're covered in carpet which
disconnects the feeling of the stairs a little bit.

In all cases where I mentioned dropping the bottom of the riser below
the level of the tread I meant by notching the riser to fit between
the stringers.

I did think about doing the lock joint by only extending the top ply
of the tread into a dado in the riser. That would save a lot of setup
and milling time. However, it does seem like it might allow the two
plys to separate over time.

Believe it or not, that drawing is actually an Excel spreadsheet.
People look at me funny when I tell them, but I do most of my drawing
in Excel. 95% of my needs are just boxes, text, and horizontal and
vertical lines. Excel makes it so easy to add shading, colors, rotate
the text, change the fonts, etc. It works great for me. The trick is
to not start out by using a single cell for a box. Start by selecting
the entire spreadsheet and setting the column width to 2. That gives
a close approximation of square cells. Then use multiple cells to
start making boxes. It's just like using graph paper, I guess. In
this case, I only needed to draw down to 1/4" so I decided up front
that each cell would represent a 1/4" x 1/4" box. Then, to make it a
jpeg for the website I just fired up my favorite image viewer (PMView)
and told it to capture my Excel window. I cropped the image to remove
the Excel menus and voila.

David Alexander wrote in message . ..

Before you start I would recalculate the layout, i.e. the rize and
run. I find that many times old stairways off, new ones too.
Especially when changing finish. Ideally all the _finished_ riser
heights should be within 1/4". You will probably have to do some
shimming.

Mike

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!

"Mike" wrote:
Before you start I would recalculate the layout, i.e. the rize and
run.
[snip]

Excellent advice! I'm willing to bet that David already did that, however.
IMHO, a difference of 1/4" rise between two adjacent steps is too much. I'd
shoot for +-1/8".
jj

On 9 Mar 2004 08:06:34 -0800, (Mike) wrote:

David Alexander wrote in message . ..

Before you start I would recalculate the layout, i.e. the rize and
run. I find that many times old stairways off, new ones too.
Especially when changing finish. Ideally all the _finished_ riser
heights should be within 1/4". You will probably have to do some
shimming.

When I get to the main stairwell I'll have to measure everything up
again. I last pulled those steps up to look around a couple years
ago.

As for the small set of steps I'm doing first, you wouldn't believe
how uneven they were. I measured them up before demolition so I'd
have a record. When I pulled them up I found there weren't any actual
stringers. The first tread sat on top of a 2x4 frame sitting on edge.
The second step had a 2x4 on face sitting on the first frame and then
another 2x4 frame on top of that. The final step up is to the tile.
The runs were 11-1/2" and 12". The rises were 5", 4-3/4", and 6-1/2".
My new steps will all be consistent.

At least I know the main stairs have stringers and hopefully they're
more consistent.

On Tue, 09 Mar 2004 16:13:55 GMT, Joe Willmann
wrote:

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.

I have been strongly considering assembling each tread and rear riser
as a unit off the stair and then installing them. I can do that
easily for the small steps because I know the stringers I just made
are square and consistent. I'll have to wait until I pull up the main
stairs in about a week to see exactly what shape those stringers are
in.