Hello phaux, unless there are some special considerations for your spiral staircase the kits are likely much more cost effective and easier to work with. If you become more familiar with the associated challenges for engineering, fabricating, and other details for these, then you would likely consider taking this on in a more custom fashion of your own. I'll see if I can find some of the photos that I have for examples of a couple of different types and include them here. As to the handrail, some outfits have rollers that can provide the correct diameter/pitch considerations for a spiral rail. Otherwise, there are some mathematical formulas that are used to provide the correct rolled diameter and then you need to "stretch" this diameter to attain the correct pitch. I am sure that others will chime in here and provide you with more options and great advice. Good luck and best regards, Allan

EDIT: the images and the document that I included with this post shows one spiral staircase that was a direct measure where the attachment of the stair treads was directly applied to the center post. The other examples showed a more common type where the treads are attached to sleeves so that they can be slipped down over the center post and easily indexed to the appropriate pitch. The word document that is in this post gives a mathematical formula for figuring flighting or flat bar style handrail, it can also be applied to pipe if you use the centerline dimension to determine OD and ID measurements and then apply those numbers to the formula. Hope this helps a bit or at least doesn't confuse the issue.

I have to agree with Allen. The kits are fairly inexpensive actually. I priced out custom building a spiral for a client and I could buy the kit for a lot less. You tell them the height, diameter and they can get you a price back before the end of the day. The spiral stair folks will sell steps to you. I priced them out at a machine shop and then contacted one of the companies online, think they were out of Texas. Anyhow, they were a heck of a lot cheaper than the machine shop. Actually, I think I priced out a railing from them plus treads and I was going to build the rest, powder coat, etc. It was still cheaper to just buy the kit from them!

I've priced out two spiral stairs so far. Kit and built from scratch. Both times clients said, "we're gonna have to think about it". I don't think they realize just how much spirals stairs can cost they just know they like them.

I think they are a great challenge to think ahead and really figure out details. On the other hand I think they are a sign of poor architecture and I wouldn't live in a structure that needs one. Realtors tell me the only people who buy them never had one.