Stair finish is going on soon, and here is the proposal. The stairs are made using 2×12 SPF carriages, three stringers across a 39″ stair width, and finished with 1″ oak treads and painted 3/4″ pine risers.
What is proposed here is that the treads be dadoed, and the risers rabbetted, and screws used to fasten each to the other, as shown in the included drawing. We have full access to the undersides of the carriages because we have not closed things up back there yet.
Glue, either construction adhesive or plain yellow, will be used to glue backs of treads and risers to the softwood carriages, and 12d finish nails will face-fasten the parts. Nails will be sunk and the recesses puttied.
Does this look right to you? Does it look impossible to assemble?
Not shown in the pic is a 3/8″ scotia molding that dresses the under-lip joint between each tread and riser.
Replies
I don't think it's impossible to assemble. Just remember to pocket screw the first riser to tread before the tread is installed.
Jon Blakemore
If you are talking about the first tread/riser joint as the one, at the bottom of the carriages, bearing on the landing, you are right, in that there is no access from below for a screwgun to drive pocket screws.
If you pre-paint the risers and prefinish the treads, screw from behind the riser up into the tread with pocket screws, and pre-assemble all the tread/riser sets, it may go faster. Only a few finish nails to putty where you nail to the stringers, or you could screw at an angle from the back from stringer into the tread.
I have never done this, but somehow posted to the wrong thread, sorry!.
Jake Gulick
[email protected]
CarriageHouse Design
Black Rock, CT
Edited 1/3/2004 12:13:32 PM ET by LATEAPEX911
Mr, Micro,
The only arguable reason to rebate the riser is to help conceal the joint should there be some movement between thread and riser. A good reason to forego the rebate is that you make the joint half as strong. People have a tendency to kick the riser as they go up stairs and reducing the connection to 3/8" might be a problem.
A screw holding a 3/4" section of wood would do a better job then the same screw holding a 3/8" section of wood. Butting the riser and thread with glue and screws would make a very strong joint. Plus it will take less time to make each riser.
Edited 1/3/2004 3:37:11 PM ET by Resurrected
Joe makes a good point. The bottom of the riser would lose some strength. An option might be to rabbet the tread. This would conserve the full thickness of the rise but still give you a non-butt joint. Of course, if either the riser or tread were to shrink, then you might get a vertical gap as opposed to a horizontal gap, which could conceivably collect debris.
Jon Blakemore
Don't dado the treads at the nosing!
That is where all the weight of your 300 lb. friend will come to bear as he goes down the stairs.
no place to remove material and strength.
Use glue blocks with lots of glue.
Use Contruction adhesive on the carraiges because they will have shrunk some.(even a small amount is to much gap for yeller glue)
Use an Oak scotia under the nosing.
screw the bottom of the risers to the treads with drywall screws NOT!
Get some GRK or Mcfeely's
How are you gonna fit to the skirt boards?
Have fun!!!!
Mr T
Do not try this at home!
I am an Experienced Professional!
Skirts are going on first. We will use the StairGauge tool to measure and fit each riser and tread. Tread/riser joints with the skirts are butts.
Congratulations on the nicely done 4kb sketch of the detail. I wish I knew how to do that.
I would be concerned about the strength of the tread nosings. People put their full weight right there, and I would not remove wood where it's needed. The pocket screws will probably fasten that joint adequately, although they will be hard to install on the bottom 2 or 3 steps, and in general I think pocket screws are pretty small as construction fasteners go.
I also don't think you need to rabbet the bottom edge of the risers. That only serves to change the orientation of the joint from vertical to horizontal, and I don't think it's worth it for the very slight visual advantage you'll get. You lose wood for the screwheads to grab, and you need that wood too. The downward force of the person using the stairs wants to break off the bottom edge of the riser as the treads deflect.
My solution for an exterior painted stair I'm doing now is to biscuit the top of the riser to the underside of the tread above, and screw & glue the riser to the back of the tread below without a rabbet.
Howzis? See attached. We'll butter the glue blocks with gorilla glue, and pin 'em in with air-drive finish nails. No more dados, no more rebates.
The little scotia mold (pine, primed and painted to match painted skirts, no oak available) is now shown.
Micro,
I would stick with our original plan. Your second diagram is inferior to the first design. I am not a stair builder, but have built a few stairs and as a carpenter I would never use butt joints on anything."One measurement is worth a thousand expert opinions"
"I would stick with our original plan. Your second diagram is inferior to the first design. I am not a stair builder, but have built a few stairs and as a carpenter I would never use butt joints on anything."
How do the rabbets in detail #1 add to the quality of the install?
If you have all the time in the world this is great, but I don't think it's necessary. What are you worried about? The stairs falling apart? Squeaking? If I was going to put the extra time into your stairs I would put it into your skirt boards. Cut them so the riser fits behind the skirt board, and the tread butts into it.
It's not that hard to do and the results are worth the time. This allows you to shim the riser out tight to the skirt, with at least 3/8" of the riser behind each skirt. Now, when you cut the treads a hair too snug, you aren't going to open up the joint between skirt and riser. In fact you can make them quite snug reducing the likelihood that a gap will ever develop between tread and skirt.
Are you trying to do this without any exposed nails in the treads? Is that the reason for the glue blocks? It appears that you are going to use a cove molding under the treads where it joins the riser. I would use a small bead of const. adhesive here to join the two. The small amount ot glue that may weep out can be trimmed off before it fully hardens and any remaining residue will be covered with the cove. I would use a liberal amount of const. adhesive behind risers and treads and place 2, 2-1/2" nails through the treads into each jack. (Nails from tread to riser are most likely to squeak and loosen with time, let the glue do it's job here, no nails.) Same for the risers, although I would place these nails at the top and bottom edges so that they are concealed by the tread at the bottom and the cove at the top
I don't think it's necessary to dado and rabbet anything and agree that it's a bad idea to dado the tread at the nose. I usually screw tread to riser from the back as you propose, works on all but the top tread.