Exterior Curved Handrails
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You would need a wreathed handrail for that. There are a few guys on the east coast who can make it but I don't know of anyone in GA. You may have to have it made and shipped to you.
From Contributor O:
When the rail curves while ascending/descending, it becomes helical or twister rail. It cannot be a flat curve as would be used with rail on a level plane. Contributor K is correct in that a wreathed rail would do the job (wreathed meaning solid pieces of wood joined at the ends to make the curves). Another way is to do it as bent laminations - several thinner pieces of wood bent on a form and glued and then shaped. Both methods have their pros and cons, but either will work. The difficult part is communicating the information on the stairs to the rail builder. Rise, run, radius, etc. all must be accurately described for the rail to work.
My concern about using bent lamination based on the picture would be the pitch change from straight to curved. There is not much room to ease the transition, the rail would have a good bit of twist and both top and bottom rail would need to be in plane. I'm sure it could be done but it's such an open profile I suspect solid rail might be a better choice.
From Contributor O:
A valid concern Contributor K. I have dealt with this in the past in two ways:
One, if I can I build the steps or at least design them so the run under the rail is always the same. The treads may 'belly' out for longer runs as they descend, with radius plan risers, but the run remains the same. This makes for the same pitch throughout, and a smooth bent rail is just the ticket.
The other way is to ignore the change in pitch in the stairs and set the rail at an average pitch. This makes the rail height vary from tread to tread, but in most cases it is hardly noticeable. This may violate whatever rules are in place, but the location dictates aesthetics above strict adherence, as a matter of opinion. Does code dictate in this location? Exactly what is the variance in run and the resulting difference in the rail height, and will that all work within code heights? When given the option of a kink in the rail (as one designer called it), the smoother, flowing rail was desired, and subsequently made. In fact, explaining the how pitch change (as a function of variable run lengths) is one of the biggest challenges to a railbuilder that is tasked with making rails for an existing stair that was laid out without that understanding, and where code applies.
As you know, the tread run needs to be consistent at the walk-line which requires the tread run to change at the handrail line which causes the pitch change. As described you could bend for the full run of the stair and ignore height changes, IRC is 34" to 38". You would need to mill all the laminations and sequence them. Then since it is an exterior rail it would need to be glued together with epoxy, allowed to cure, sand off all the excess epoxy and install the rail. I would prefer to make the rail, balusters, etc. in the shop and then install, but since I'm more than 3000 miles away it doesn't matter what I would do.
I can do or furnish whatever is required. Newel posts or balusters can also be supplied. All I would need is a plan in order to produce the handrail and matching sub-rail. After that any finish carpenter should be able to install the parts. As to the question of strip-laminating - the handrail or cutting it from solid timber? Either way is doable but I usually advocate solid rail especially in exterior application. (The sheer number of layered, bent strips of wood all being glued together and exposed to the elements is not something I'd comfortably recommend.)
From Contributor O:
I would do all the laminations with resorcinol glue rather than epoxy. It is better for long term, full exposure than epoxy. Epoxy has a weakness with UV exposure. As long as things paint, the purple glue line is not an issue. I would prefer to use Honduras Mahogany, but clear W R Cedar would be the next choice. I have some unpainted redwood post caps out in the weather for 30 years - the wood is eroded, but the glue line is still there, as far as anecdotal evidence. It is the glue developed for the Spruce Goose, if I recall correctly, and still specified for wood airplanes today.
To the original questioner: Southern Staircase Company in Atlanta could probably do this job complete although I'm not sure if they would want to.They stock and install standard stairs and parts for interior work.
To contributor O: One claim suggests that resorcinol glue was invented in England and used in the production of the De Havilland Mosquito bomber. That would date it to 1943 and prior to Spruce (birch) Goose. Before that plywood was made with soybean glue which fungus loved to eat. I concur with your material suggestions and observations. I built an exterior, white oak/resorcinol spiral stair, which is reported to be in good condition after 25 years.
From Contributor Z:
We can easily build this for you. We have a five axis router and can machine the rails from any wood you would like. You can contact me through our website www.deasmillwork.com. I can shop this to you for you to install. I can even recommend an install company in your area if you would like.
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