Spiral Staircase Specifications,

Planning and Installation Tips
Spiral Staircase Prices
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Prices for all spiral stairs
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Decorative options

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What's in the Precision Pine Spiral Stair Kit

Spiral stair kits from Precision Pine provide everything you need for free-standing, decorative, all-wood staircases that can be installed by two people who have a general knowledge of carpentry techniques and tools.

Stair parts are manufactured from selected pieces of your choice of wood: Southern Yellow Pine, Red Oak or other species. Parts are sanded to 80-grit smoothness and where possible pre-drilled for fasteners. Fasteners are hidden with wood buttons, plugs and caps. Final staining and varnishing is done by the customer.

Kits can be ordered to suit any floor-to-floor height. Six standard diameters are available: 6'-0"*, 5’-7"*, 5’-1”*, 5’-0", 4’-6", and 4’-0". (The diameters marked with an asterisk meet national building codes.) Stairs with custom diameters are also manufactured.

All parts required for the spiral stair installation are supplied in the kits, including the top landing and its horizontal rails. While national codes are fairly uniform, some local codes may have special requirements. Precision Pine will supply any additional parts required to meet these requirements at no extra cost.

Kits typically consist of a base plate and a pre-built bottom tread that fastens the spiral to the lower floor. Partially assembled pre-drilled treads and stiffeners are glued together at the start of installation to suit whether the handrail will be on the right or left as you climb the stairs. Final finishing of the stair parts can be done before installation or afterwards. However, if finish is applied before installation care should be taken not to contaminate the wood surfaces to be glued.

The kit provides separate riser blocks that are stacked with the treads to form a central column and a top center post that rises to a comfortable handrail height above the top floor. Before installation is complete the treads, riser blocks and top center post are tightened firmly together to form one solid unit with the treads embedded in the center column. The top landing is level with the top floor and fastens the spiral to it. Horizontal handrails protect the landing sides that are open to the stair below.

All kits are supplied with at least three 1-1/4" x 1-1/4" square balusters per tread, enough to reduce the space between balusters to less than 4". The top and bottom spiral handrail (newel) posts are 2-3/4" x 2-3/4" square. Turned (decorative) balusters and newels are available on request.

Required hardware, graphic assembly instructions and expert technical assistance from the factory are included.

Four styles of spiral kits

Spirals can be ordered in four styles: The Traditional Spiral, the Contemporary,the Charleston, and the Orleans. In addition, the Smart Spiral lends itself to exterior applications for outside decks.

The Traditional Spiral

The Traditional Spiral kit is available in pine, Red Oak, or other wood species. It is supplied with a traditional solid wood spiral rail that is usually shipped in a single piece. The one-piece rail has a square cross-section about 1-5/8" thick and 1-3/4" high, to meet graspability requirements of national building codes.

The Traditional style comes with a square center column.

Balusters may be installed on the outside of the one-piece rail and outside the tread perimeters; or the same balusters may be cut and installed under the rail and on top of the treads.

The Contemporary Spiral

The Contemporary spiral stair features a wider one-piece handrail (1-5/8" thick by 4" high) and a round center column. This style is available in pine, red oak or other woods. You should consult your local building code to assure the wider rail will meet graspability requirements. Precision Pine has rail details for you to show your building inspector.

Smart Spiral Option

The Smart Spiral is made of Southern Yellow Pine and features the patented wood Smart Spiral Handrail assembly (U.S. Patent No.5,535,557) and square center column. This spiral rail is called "smart" because it "figures out" its own shape as it is being installed.  The Smart Spiral block style handrail provides an entirely new look and design for spiral stair handrails (a close-up photo of this rail is shown on the pricing page). It is priced less than traditional spiral rails and costs less to ship so the customer can save.

Balusters are attached to the outside of the Smart Spiral handrail and to the outside of the tread perimeter.

The Charleston

The Charleston comes with a one-piece rail and turned (decorative round) newel posts and balusters. The Charleston has a round center column and is usually ordered in red oak or other hardwoods.

The Orleans

The Orleans style combines the beauty of wood with the ornate strength of wrought iron. This exclusive style is manufactured in Red Oak or Southern Yellow Pine and features wrought iron balusters, turned wood newel posts, decorative bracket, a rectangular ( 1-5/8" x 1-3/4")one-piece spiral handrail and a round center column. Customers may choose which baluster styles they prefer.


Exterior Smart Spiral stairs are made of pressure treated yellow pine and use all stainless steel hardware. Exterior kits do not include the top landing deck or horizontal rails since these can be constructed with commercially available deck lumber.

Mix and Match Features

Some of the features of the four styles can be substituted with any one style as a custom order. For example, you can order the Smart or Traditional spirals with a round center column. You can order the Contemporary wide rail for the Traditional style. Or you can order turned balusters and newels for the Traditional style.

You can order a spiral with some features left out to reduce the price. For instance, you could order any style without the top landing rails or the top landing itself.

Custom Kits

Precision Pine offers wood spiral stairs that are built to the customer's specific orders. You can order a custom kit for any height or diameter as long as Precision Pine can assure it will fit in your floor plan. Custom spirals may turn less per tread. You can order large diameter spirals with lower rises between treads than standard kit spirals. Custom spirals may also include traditional turned (round, decorative) balusters and newel posts. Prices for custom kits are quoted on a case-by-case basis. Precision Pine can also design a spiral stair that flows into a straight stair.

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Spiral Stair Planning

Planning Assistance

Precision Pine works directly with each customer to assure the staircase ordered will suit his or her needs. We will help you with positioning your spiral, ascertaining proper floor-to-floor height, and ensuring adequate clearances.

When Precision Pine plans your spiral stair the diameter is usually based on code requirements, the space available, clearances to any nearby obstructions and anticipated amount of use. We recommend ordering as large a staircase as possible for additional comfort.

The floor-to-floor height determines the number of treads required and this sets the total amount the stair will rotate as you climb it (4'-0", 4'-6", 5'-0", 5’1” and 6'-0" spiral treads turn 30 degrees each; 5'7" spiral treads turn 28 degrees).  With the total rotation known we plan the position and orientation of the staircase for the best access to the top and bottom floors.  We check that there will be adequate headroom at all areas of the spiral.

Precision Pine will send a final version of the plan for the customer's confirmation before manufacturing.

Tools, Other Materials And Time Required

The installer will generally need the following tools and other materials:

Tools: A wood saw (an electric miter saw is ideal), hack saw, hammer, no. 2 square drive screwdriver or bit driver for an electric drill, wrenches (1/2" and 9/16" sockets; 1/4" and 3/4" closed end; either one 1-1/2" and a 1-3/8" open end wrench and a medium size or larger pipe wrench, or two pipe wrenches), locking pliers, electric drill (with bits of 1/8", 3/16", 1/4", 3/8", 9/16", 1/2" and 1" diameters), 24" bar clamp, two 6" C-clamps, and two 3" spring clamps. Additional clamps are always helpful.

You may need additional or fewer tools depending on your carpentry expertise, special installations, floor makeup and design, and/or future design improvements in the stair kits themselves.

Materials: 2x lumber for temporary bracing of stair top and 1x lumber for temporary handrail supports.

Assembly of these kits is straightforward, although a different process from building a straight stair. Stair installation takes about 8 hours for a skilled carpenter with prior experience with our stairs. Allow additional time for working around obstructions. Thos without experience with our system usually take two to three days. At least two people should be on hand to install the stairs.

Precision Pine will send out assembly instructions well ahead of delivery of your kit. We strongly recommend that you and/or your installer read and understand the instructions BEFORE attempting to install the stair. Installation will go much faster once the process is understood.

We encourage all customers with questions to call us before beginning assembly. Call 1-877-885-8902 toll free (weekdays 8: a.m. till 4:30 p.m. EST) for help and support from our staff. With pre-arrangement we could plan to contact you when our offices are closed.

Suggested Clearances For Spiral Stairs

Precision Pine recommends a clearance of two inches from any nearby obstructions to the stair perimeter. (For example a square opening in the top floor with FINISHED dimensions of 5’-4" by 5’-4" will comfortably accommodate a 5’-0" diameter stair.) Stairs have been installed in slightly tighter openings. The 5'-1" spiral has been specifically designed to fit in a 5'-4" by 5'-4" opening. However, if you order a Smart Spiral or Contemporary style, you should provide a finished opening of at least 5'-6" by 5'-6".

Headroom Considerations

Adequate headroom must be provided as you pass under the top landing edge, and under the ceiling above the landing. Precision Pine plans minimum clearances of 6'-6".


Final positioning of the spiral is determined by the final size of the top landing. The top landing parts are supplied a bit longer than necessary in case an obstruction is not apparent during planning.

The staircase should be positioned so that it doesn't interfere with walls, doorways, windows, interior trim materials, light switches, thermostats, receptacles etc. Remember the recommended clearance is 2" beyond all parts of the stair perimeter, or 4" overall. If you need to position the stairs closer to an obstruction let us make appropriate recommendations.

Floor-To-Floor Height

Floor-to-floor height is the vertical distance from the finished surface of the lower floor to the finished surface of the top floor. Each spiral staircase is set to match the customer’s floor-to-floor height, so an accurate measurement of this distance will be required when ordering. It is important to consider what finish flooring (hardwood, carpet, tile, etc.) might be added over the subfloor of either floor. The thickness of the finish flooring on either floor can increase or decrease the total floor-to-floor height.

Precision Pine will make the appropriate recommendations and adjustments to the floor-to-floor height after discussing these points with the customer. If you are estimating the approximate floor-to-floor height for a price quote, remember to add the thickness of the top floor system (often 10-1/2" or more) to the ceiling height over the lower floor.

Stair Orientation

Stair orientation involves which way the staircase will turn and the best direction to get on and off the stairs. Your floor-to-floor height will determine how many treads are required, therefore how much the stair will turn from top to bottom. As you climb a RIGHT HAND staircase the handrail will be on your right. A LEFT HAND staircase handrail will be on your left. Usually you want to step onto the stairs with a clear access from an open part of the room, and exit off them into an open area. When possible some customers orient the stairs to enhance the visual effect on the lower floor.

Tall and Stacked Spirals

Spiral stairs may be ordered to suit any floor-to-floor height, but particularly tall units (usually floor-to-floor dimensions above 12 feet) may require permanent side bracing. Precision Pine advises customers when this is necessary and supplies side bracing at no additional charge.

Stacked spirals may be ordered to climb between three or more floor systems. In these cases the upper staircase starts up from the lower staircase top landing.

Building Codes

Because of the geometry of a spiral staircase, all the model codes in the United States have basically the same requirements for spiral stairs. These rules are considerably different than those for straight stair systems.

Spiral code requirements are:

Maximum rise: 9-1/2" (this is higher than the maximum rise for a straight stair because you have to go down a spiral more steeply to gain sufficient headroom under the top landing).

Minimum headroom: 78".

Minimum horizontal width of tread: 7-1/2" at a point 12" out from the center column.

Minimum width of clear passageway: 26" from the inside of the handrail to the outside of the center column.

Baluster spacing: most codes require a space of no more than 4" between balusters.

Minimum opening between treads: some codes require no more than 4".

Before putting your package together at the plant, Precision Pine will need to know if local building codes will govern the installation of your spiral staircase. If so, we prefer to contact the local inspector either directly or through the customer to assure that the installation will meet local requirements. Regardless of the exact wording of building codes, the local inspector will be the final authority on the interpretation of code requirements and what or when allowances can be made. It is best to find out the exact requirements before installation begins.

Horizontal Top Rails

You can specify the type of top landing rail you prefer. Photos on the balcony rail page show the Standard and Slimline rail systems.

You can also order additional rail materials to block off open stairwell and balcony edges. Rails, posts, balusters and hardware are included to fit your floor plans.


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Precision Pine, Inc.,
7322 Hodges Ferry Road,

Knoxville,Tennessee 37920

Phone (865) 573-5322
Toll free (877) 885-8902

Fax (865) 573-0143

email: spiralstairs@earthlink.net