How to Build Stairs
The construction of a stairway using iron balusters or wood balusters is a matter of patience. Anyone who has mastered the basic tools for finish carpentry can install their own stairway and get fabulous results.
How to understand Stair Terms (Glossary)
How to Bend Handrail (PDF Instructions)
How to choose what to order (Ordering Guide)
How to Understand Stair Parts (Anatomy of a Stairway)
Here are few hints before you begin your stairway.
- Layout everything before you make the first cut. Plan your baluster line, prepare where your newels will be placed and plan the height of your handrail.
- Do not pre-cut all of your stair treads, stair risers, balusters or iron balusters. Each part should be cut to fit.
- If you are doing a bending handrail, you will want to bend the handrail first before installing treads or any other items. After the handrail is bent, begin to install starting steps, treads, risers, skirt boards, and newels.
- Most installers find it easier to install handrail first, then install balusters. Most balusters will slip into the handrail and down into the tread or landing tread.
- When installing treads be sure to scribe and cut each tread to fit the opening this will ensure a tight fit and eliminate the need for putty.
Layout
The blueprints of your home should include a layout for the stairs; however, many residential drawings give only rough guidelines for the stairway and the actual building of the stairs is left to interpretation by the framer and finish carpenter.
Start the layout of your stairs by determining the height from floor to floor. This needs to be a measurement from finished floor to finished floor. If you have hardwood flooring, tile or carpet these all need to be considered in the layout. This is what we will call the height of the stairs. The next measurement is the length of the stairs. Measure the distance from where the first riser will begin to the the face of the second floor where the stairs ends. These measurements will help to determine how many treads and risers are needed. A very comfortable stairs will have rise of 6 3/4″ from the top of the tread to the top of the next tread and a run of 10″ from the face of one riser to the face of the next riser.
Example: If your finished floor to finished floor height is 120 inches then divide 120″ by 6 3/4″ which equals 17.78. Rounding to the nearest number we determine that there will be 18 risers in this stairs. 120″ divided by 18 risers provides us with a rise of 6.67″. If we want the run (distance from front of riser to front of riser) to be 10″ then the stairway length will be 17 (one fewer than the number of risers) multiplied by 10″ equaling 170″. You will use 11 ½” treads for this stairway which will give an overhand of 1 ½” over the riser and standard risers which are 7 ½” inches can be cut down to 6.67″
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Stringer Construction
The stringers are constructed by marking with a framing square the rise and the run for each step and notching the waste pieces. On a framing square place a stop at the riser 6.67″ (from our example above) on one side of the square and a stop marking the run at 10″ on the other side of the square. Starting at the top of the stringer place the square on a 2″ x 12″ piece of framing lumber and draw lines indicating the rise and the run of each step. Move the square down one step and repeat the marking process. Stairways 48″ and narrower should have 3 stringers supporting them. Stairways wider than 48″ should have 4 stringers. Cut the notches out from the first stringer and mark it as pattern. Now is a good time to hold your first notched stringer in place to ensure that it was cut properly. If it is cut properly use the pattern to mark the other stringers. Notch all of the stringers. When notching the stringers us a circular saw to make the cut but do not over cut the lines since this will weaken the stringer. Use a handsaw or jig saw to complete the cut so that the maximum amount of uncut lumber is intact. If one of the stringers is to be attached to a wall install a 2 x 4 between the wall and the stringer this will provide enough space for drywall and a finished skirtboard to slide in the space between the stringer and the drywall. The stringers should be attached using common framing techniques and fasteners. Some people will install a 2×4 or 2×6 to the stringer on a long stairway as a “strong back” to give the stringers more strength and less flex. After the stringers are installed tack temporary treads made from 2x10s to provide construction steps. Install a temporary railing system from 2x4s as a safety railing for use during construction.
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Installation of Skirtboard and Risers
In the closed side of a stairway the skirtboard is to be slipped between the drywall and the stair stringers. The skirtboard should be notched at the top and the bottom to so that base trim will join to the skirtboard. There are several methods for joining the base trim to the skirtboard, but they are beyond the scope of this article. The skirtboard should be installed so that the top of it is 2 ½” above the finished tread.
In the open side of a stairway the skirtboard needs to be notched. The most professional and difficult method is to miter the vertical notch of the skirtboard and miter the end of the riser to match. Using the techniques explained above for stringer notching this can be done. A simpler solution is to notch the skirtboard and cut a dado in the back of the riser so that the riser covers the raw edge of the skirtboard and overhangs the skirtboard by ¼”. The easiest solution is to notch butt join the skirtboard and riser and use a piece of handrail fillet or other molding to cover the joint between the riser and skirtboard.
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Installation of Treads and Risers
Stair treads should extend past the face of a finished riser by 1 1/8″ to 1 ½”. Treads should be 1″ thick or thicker and should be attached directly to the stringers. Treads should be installed with construction adhesive or a good polyurethane glue and trim headed screws and finish nails. No less than two finish screws into every stringer to minimize the potential for a loose tread over time. Finish nails are not adequate as the only means for holding a tread to the stringer since they can work looks and allow the tread to squeak.
Before installation of treads and risers layout all of the treads and risers in the positions that they will be in at the completion of the installation. Move treads and risers around for the most appealing blending of colors and grains. Start your installation of treads with the first step. Remove the construction tread. Before installing the first tread, install the first riser (see below). If you have a closed tread system it is suggested that you install a riser then a tread and repeat. If you have an open system the risers should be installed with the skirtboard prior to the treads. Lay a tread flat across the stringers shim and shave the stringers as necessary so that the tread lies flat across the notches in the stringer. If the treads are single return or no return, then cut the end rough end of the tread and apply a small amount of polyurethane or other finish to the end grain. Treads are typically produced slightly oversized and are designed to be cut. If you are fitting up against a skirtboard you may need to scribe the fit so that the end of the tread is flush with the skirtboard. Since end grain is the most susceptible to gaining and losing moisture which is the cause of cracking, the application of a finish will slow and hopefully prevent this process. For best long term results a coat of finish applied to the back of the treads will lessen the chance of movement which causes cracks, and squeaks. When the tread is fit to the stringers remove the tread and apply an adhesive to the stringers and install screws and nails. Move to the next tread up the stairway.
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Bending Handrail
A bending handrail should not be intimidating or difficult, but it requires 4 hands, 2 clamps for every foot of handrail, special elbow brackets and proper planning.
Determine where the newel posts will be located and mark these locations. Construct very very strong 90 degree brackets and fasten 2 of them to each construction tread for an inside radius and 3 or even 4 brackets for an outside radius. The elbow brackets form the line to which the handrail will be bent. Lay the handrail against the elbow brackets and dry fit the procedure.
Bending handrail is comprised of 7-9 layers of handrail and two outside forms. Set the forms aside and apply a generous amount of glue between each of the layers of the bending handrail. If possible use a slow setting glue, if a slow setting glue is not possible then work fast. It is important to have 2 people working this process. The handrail should be assembled with glue between all of the layers and the forms on the outsides do not get glue on the forms and the handrail or it will be difficult to remove the form from the handrail. Wrap the entire assembly tightly in several places with stretch wrap to make it easier to handle. Place the handrail on the construction treads and against the the 90 degree brackets. Begin at the bottom of the stairs apply clamps to the handrail and the angle brackets. Be careful not to allow gaps or twists in the layers of the handrail. Wipe excess glue from the handrail. Do not use water or you may weaken the glue joint or cause sunken glue joints. Allow the handrail to be clamped and to dry for 24 hours. After removing the clamps remove the excess glue with chisels, scrapers, and a belt sander. Cut the ends of the handrail and install fittings so that the handrail can be attached to a newel post.
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Installation of newel posts
Newel posts are necessary every time that the handrail changes direction. A newel post is also necessary on balconies where the length of the handrail is 8 feet or more. Local building codes may require newel posts in other locations. Check with your building inspector for more information.
For installation of pin top newel posts determine the height of the newel post by calculating the height of the handrail at the point where the newel post is to be installed.
For installation of a post to post system calculate the center point of the block on the newel post and ensure that it aligns with the center of the handrail. For balcony handrails the minimum handrail height is 36″ some local codes require 42″ handrail height.
The use of a sure-tite newel fastener is recommended for installing newel posts since it is the strongest mechanical fastener available. When installing a newel post it is recommended that a a level is clamped to the sides of the newel and the newel is installed plumb.
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Attaching fittings to handrail
To attach a handrail to a fitting it is imperative that a clean, flat cut is achieved. Use clamps and blocks to hold the part being cut in the saw. It is impossible to hold a part in the saw with hand pressure only and achieve a quality cut. To calculate the angles for cutting upeasings measure the angle of the stairway with a protractor or set the fitting on a step and use a plumb bob to mark the angle for cutting the upeasing.
When a good dry fit is achieved for the handrail and the fitting use a rail bolt kit to attach the fittings. Find the center of the fitting and drill a hole in the fitting and insert the rail bolt into the fitting. Drill a hole in the center of the handrail and drill a hole in the bottom of the handrail as an access hole for tightening the bolt on the rail bolt kit.
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Baluster Spacing
Most installers prefer to install balusters after the handrail is installed. The general consensus is that it is easier to adjust baluster position to fit the handrail than it is to measure, cut, fit, and attach both the handrail and the balusters at the same time. Therefore, this document will explain the installation of balusters after the handrail is installed.
Most codes require the installation of balusters in a spacing so that a 4″ sphere cannot fit through the balusters at any point. Therefore for 1 1/4″ wood balusters plan on a spacing maximum of 4.25″ on center. For 1 3/4″ balusters plan on a maximum spacing of 4.5″ on center. For installation of balusters in a balcony measure the distance where the balusters will be installed and divide the distance by 4 round up to the nearest number and subtract one. This will give you the number of balusters needed for the given space. For instance If the distance is 49″. 49″ divided by 4 equals 12.25 Round to 13. Subtract 1 which equals 12. Therefore 12 balusters will be needed in this space. To find the on center baluster spacing: 49″ divided by 12 equals 4.08″.
Mark the baluster spacing on the landing tread where the balusters will be installed. It is suggested that masking tape be installed where the hole will be drilled to reduce tear-out. Install the masking tape first so that the marks do not need to be transferred. Using a laser or a plumb bob mark the position in the center of the handrail where the baluster will be installed an mark the position on the landing tread.
To find the baluster spacing on standard stair steps you will find that to meet the 4″ sphere rule you will need to have three balusters per tread. Measure from nose to nose of a tread to find the length of treads. Divide the length of tread by 3 to find the on center spacing. Start at the bottom of the stairs and move from the newel post the appropriate spacing adhering to the 4″ sphere rule. The first baluster from the newel will give you a reference point to measure your on center spacing. Make sure that the balusters fall at the same point on every tread.
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A compilation of requirements, tips and advice on installing stairway parts. Be sure to consult local building codes to be sure that you are in compliance before building a stairway.
Products should be inspected immediately upon receiving them and installed as quickly as possible. Stair parts should be finished on all sides (especially stair treads) to reduce the possibility of warping or cracking.
Buy the right tools for installation. Our specialty tools such as rail bolt wrenches, dowel screw driver, epoxy gun and sure-tite newel fasteners make a job much easier.
The right tool for the job of cutting iron balusters is a bandsaw, but a reciprocating (sawzall) saw, hacksaw or cut of saw with an abrasive blade will do the job.
Upside down balusters can save a lot of time in installation. Try plowing a half inch strip through the middle of your handrail and mounting your balusters upside down (with the round dowel end drilled into the tread). All epoxy isn’t created equal cure times and holding strength vary greatly. Our epoxy is designed to have the proper working time and the strength for a stairway application.
Do not precut all of the balusters before installation. Setting up a stop block at your saw is helpful to for as a guide, but each baluster should be measured before cutting, because handrail height may vary from tread to tread. Wrap tape around the the top of iron balusters so that any epoxy that runs out of the hole will run onto the tape. After the epoxy has cured, remove the tape and the excess epoxy will come with it.
Dowel screws for installing wood balusters will save lots of headaches in the future. Dowel screws firmly hold balusters in place for years where wood to wood installations tend to work loose over time. A laser plumb tool is an excellent for ensuring that iron balusters are installed straight. It is much more noticeable if iron balusters are not installed perfectly plumb than it is with wood balusters.