[B.D.R.]

Thought I would post a head scratcher, (at least for me).
Forming a tightly curved railing , with poured concrete stairs.
The concrete is about 60 yrs old.
I'm worried about breaking the concrete if we try to drill into it for the forms.
Rises and runs are all different.
Any suggestions?

 

[B.D.R.]

Another angle.
Don't want to walk away, but I might have to.

 

[Aframe]

You say "drill into it for the forms". Are you pouring a kneewall for rail or just templating for a hand rail?

We did one similar and used "wacky wood" plywood on a framework along inside curve. Then measured up from treads and used blocks and strips to fabricate a template rail.

 

[B.D.R.]

We have steel uprights that we usually fasten to the treads.
Then we can pull the bending strips around the uprights to form the rail.
Needs to be solid.

 

[Eaglei]

I think I understand your concerns as far as fastening your steel uprights . These uprights are only going to be fastened temporarily so you can form your handrail or are they going to also be used as permanent spindles ? If they are temps couldn't you clamp them down with pipe clamps and cut some angled pieces of wood for the bottom side of the staircase so the clamps won't slide . If they're going to be permanent I would drill holes maybe half way through the treads. To keep the treads from cracking I would drill slightly bigger diameter holes for the uprights and then fill with a non hardening elastomeric polyurethane such as sonolastic sl-1 or similar . Then I would fasten them with Tapcons .

 

[Kowboy]

Screw a 4'x8' sheet of plywood to the floor at the inside radius and plumb down from each tread. Copy and cut the arc to another sheet of plywood to make a top plate. Build a temporary curved stud wall with the plywood as top and bottom plates. Your handrail will be dictated by the points created by front edge of each tread meeting the temporary wall. Your rail will fit perfectly and you haven't drilled the concrete at all.

 

[B.D.R.]

They are temporary.
Your suggestions are definitely helping.
Thank goodness they want paint grade and metal spindles

 

[B.D.R.]

Screw a 4'x8' sheet of plywood to the floor at the inside radius and plumb down from each tread. Copy and cut the arc to another sheet of plywood to make a top plate. Build a temporary curved stud wall with the plywood as top and bottom plates. Your handrail will be dictated by the points created by front edge of each tread meeting the temporary wall. Your rail will fit perfectly and you haven't drilled the concrete at all.

I have read this over and over again, ( guess I'm a little slow ).
It is finally making sense to me.
I was trying to figure the top plate on the curve, but now realize that it is just a wall.
Getting the twist in this will be fun.
I'm thinking that poplar might be the best wood for this.
Hemlock or fir might be too brittle.
I'm not sure but I think the owner used to be the drummer for the Powder Blues Band.
Thanks for the help with this.

 

[Railman]

Normally I'd do something to what KOWBOY suggested. The problem I see is that the curve is not even, neither is the radius.

I'd probably tapcon a full tread 2x6 along the nose of each tread, & do your bending form work on top of that. You might consider a bead of acrylic painters caulk to help with adhesion. The added length of the long 2x6's will lessen the load on the tapcons, hence reducing a chance of pops in conc.

Another way might be to bend a soft aluminum box tube (maybe 1" sq?) to the curve needed, & model a wall cylinder in your shop to fit curved aluminum template.

That is a tight radius, & even poplar will be a chore to get bent. I'd probably wet the stock before bending.
I'd stay away from finger jointed bending stock also.
At any rate, good luck!
Joe

 

[ScipioAfricanus]

Could think about fastening the up-rights to the sides of the treads instead of to the top of the treads.

Andy.

 

[B.D.R.]

The uprights that we have are L shaped one inch tubing.
Curved railings don't come around often enough to make another investment.
Thanks for the advise. I will think about accepting this job.
The wall method may my choice.
Have to see what the guy is willing to pay.
Will update this post next week

 

[Kowboy]

"The problem I see is that the curve is not even, neither is the radius."

How is this relevant? A plumb bob would even transfer an ellipse to the temporary plywood floor.

 

[Railman]

"The problem I see is that the curve is not even, neither is the radius."

How is this relevant? A plumb bob would even transfer an ellipse to the temporary plywood floor.

Your right.
Normally you just do a curve wall form at a given radius, but what you said will copy the uneven aspects to the plywood template. I didn't quite read all of you post (plumb bob) when I first answered, but I did catch it right after my post.

I still think it can be done simpler/cheaper in place, but your method is definitely a good, maybe better option. It will probably come down to $.

Joe

 

[B.D.R.]

I'm not sure how much he is willing to spend on this .
$4-5 grand.
He doesnt have much of an alternative, as there is no railing now.

 

[Railman]

Another option would be to do 2 2x4's in an L over the riser, & the tread. Fasten on 2 tapcons on the riser, & 1 on the tread. That way the clamping load would be on the riser, at right angles to the screws, & eliminate pullout.