What Size Precut Stair Stringer Do I Need

How to Measure out for and Cut Custom Exterior Stair Stringers

Author: Matt Dunkin

Photos: Dreamstime

Illustration: Len Churchill

Published: August September 2019

stair stringers

With a logical approach, and a little know-how, creating custom stair stringers tin can be an efficient and enjoyable project.

Just because pre-cut stair stringers are sold in many building supply stores doesn't hateful they will be all-time for your outdoor project. Stairs are a connection between two unlike elevations and the best results are reached by creating a custom stringer built for the specific site atmospheric condition you volition come across. The result of using off-the-shelf stringers to construct a set of deck stairs volition nigh always lead to an inequality in riser tiptop at the top or bottom of the stairs, which can be unsafe for climbing. In the built surroundings your trunk makes assumptions that stairs will be consistent in height, and when they're not people can trip and fall.

I retrieve people often avert cutting their own stringers because they are intimidated to do so, and yet it's an easily attainable and rewarding skill to possess. I'll walk yous through how to measure for, mark and cut a pair of stair stringers for a deck that volition fit consistently every time so you tin can approach your adjacent stair-edifice project with confidence.

Checking Rise
Using either a long level, or a level attached to a long piece of textile, residuum one end on the upper deck surface, and adjust for level. Mensurate from the underside of the level or straight-edge to the point where the stairs volition sit to determine your overall rise.

Triangular Plywood Guide
One option to mark the cuts is to cutting a piece of plywood into a triangle, with ane border the rise and some other the run. Adhere a cleat to the hypotenuse and apply it to mark the stringer.

Carpenters' Square Guide
A carpenters' square, equipped with stair gauges, will allow you to mark the cuts needed.

Brand the Cuts
A circular saw is a mutual way to make most of the cuts. The remaining material on the underside of the stringer will have to be cut with a hand saw.

Identical Stringers
Rather than risk making stringers that aren't identical, after cut the first one, and ensuring it'south correct, lay the cutting stringer on top of the other, clamp it in identify, and mark all of the cuts.

Rise and run

Stair basics include understanding that each set of stairs has a total rising and full run, and an equal incremental ascension and run for every step of that stair. The individual run of a stair step is chosen its tread, typically a 2x piece of lumber that your feet will step on, and a 1x riser forms a bulwark to cease your toes from going through, and gives forcefulness to the tread'due south leading edge. Showtime you need to effigy out the total ascension and run of the ready of stairs, and to do then yous'll demand to determine what you'll be using for stair treads, how steep you want the stairs to be, and locate exactly where they will country.

Using 2 2×6 stair treads separated past a one/4″ gap for water drainage is standard, but yous could get with 1 2×6 abreast a 2×eight if you want a deeper tread and more gentle stair climbing feel. You'll next need to figure out if the risers volition be open, or if you will be adding a riser board. When you lot add up the width of the tread boards you'll exist using, plus the spacing gap between them, decrease the width of the riser lath and decrease the overhang you want and you volition be left with your stringer tread cutting length. For example, with a double 2×6 tread with riser it would exist 5-ane/2″ board + 1/4″gap + 5-1/2″ board – 3/four″ riser – 3/4″ overhang, equaling 9-three/4″. And so you know that for every step yous volition come out horizontally 9-iii/4″ from the edge of the deck'due south brim board.

Measuring ascension and run

If you're building a set of stairs from one level deck or platform to another the adjacent step is relatively easy, but if you lot're trying to figure out where the stairs volition country on sloping or uneven ground yous'll need to hone in somewhat through a process of estimating, and then refine your measurements when you figure out how many risers and treads there will be. The lesser of your stringers will ideally country on a flat surface that will non shift seasonally — such as a concrete pad with proficient drainage beneath it, or asphalt, limestone screenings, etc.

To start to measure for total rise place a level (or a level on a directly piece of lumber on border) on the top of the deck and cantilever it overtop of the lower area where you want the stairs to land. Y'all may need to enhance or lower it to get it level, so measure from the underside of your straight-edge to the footing. Allow's say your measurement is 47″. Take that measurement and divide it by a vii″ boilerplate riser height. Yous get 6.7 risers, and then you'll need to circular up to seven risers for your stairs. Dividing 47″ past 7 risers yous'll end up with seven risers at vi-11/xvi″ each. You'll need ane less tread than you volition number of risers if you step downwardly from your deck to your first stair tread. So, knowing that your tread depth is ix-three/4″ (or any you have decided from your earlier calculations) you lot will multiply that by your six treads and come with 58-1/two." Ensure your level or straight-edge projects out at that distance from the leading edge of the deck and check your full rise measurement. If the ground has sloped y'all will need to recalculate a more accurate riser acme. Let's say you lot re-measure out 47-three/4." That will exist your total ascent, which divided past seven risers volition give you a stringer riser cut height of six-xiii/sixteen″.

Mark

The side by side pace is to marker your private rise and run triangles onto a piece of lumber. What cloth should you utilise for your stringer? Pressure-treated or cedar 2×10 or 2×12 can be used depending on the depth of the cut-outs you'll be using. By lawmaking you will need a minimum of 3-one/2″ of fabric left on the stringer later on the cut-outs and that area should too be free of large knots which would weaken the stringer. Make certain y'all crown the lumber and have the bow of the lath facing up then it volition improve resist sagging over time.

Place your stair stringer board on top of a pair of sawhorses lying apartment. You can now use one of ii methods to mark out your stringer. I simple way to practise this is to take a slice of chip plywood which is square on ane corner and measure your riser acme on ane side and your tread side on the other. Draw a line between the 2 marks and cutting the line cleanly and accurately (inaccuracy at this stage will chemical compound later on). The hypotenuse, or the long side of the resulting correct-angled triangle, will travel up the leading border of the board always staying flush with it. You tin proceed the long edge of the triangle aligned with the border of the stringer past screwing a wood cleat to the edge of the triangle.

Alternately y'all can use a framing square and a fix of stair gauges, small spiral-on stops that will allow you to use your framing foursquare more consistently to slide up and down the lath referencing its edge. Identify your stair stringer board (two×ten or 2×12) across a pair of sawhorses and place the foursquare flat on top of it. Using the inside measurements on the square adjust the placement of the square and then that it aligns exactly with the edge of the board corresponding to your ascension and run (6-13/16″ of rise and ix-3/4″ run from the example above). Set your stair gauges so that they volition allow you to repeatedly mark that consistent triangle on the stringer board.

When laying out the stringer you will need to empathise that the first riser will not exist on your stringer — information technology is the distance betwixt the top of the deck and the top tread of the stairs. Starting at the superlative of the board yous will replicate a series of triangles, which will become your stride cut-outs. For the instance stairs above you volition depict on seven triangles with the tips of each triangle meeting at the edge of the board exactly, sliding your triangle guide or square along the board border.

Next you will make two marks, which will allow your stringer to meet the ground and the deck. The bottom riser you will have to cut shorter than all the others by one thickness of your decking, then draw a line parallel with the bottom tread cutting-out marker to a higher place it. That volition drib the entire stringer, but you will add that meridian dorsum to each pace as you place the bodily treads on and a consequent riser height will be maintained.

For example, if yous will be using 2×half dozen decking (that's one-1/2″ thick) you volition be cut the bottom riser brusk by 1-1/2″. At the top of the stairs you lot will have to mark a line down through the stringer perpendicular to the back of the top tread. This is where the stringer will butt into the rim joist or skirt board of the deck to which it is fastened. At this betoken double check that y'all accept the right number of risers and treads before proceeding to cutting.

Cut the stringer

With the stringer across two sawhorses take a circular saw and make cuts into the right-angled intersection betoken where the riser and tread see, raising the guard on the saw for starting the cuts where it volition otherwise demark. Accept a hand saw and finish both cuts making certain non to over-cutting and weaken the stringer. Yous will exist left with a saw-toothed stringer and a series of triangular cut-out scraps. At this indicate take a minute to clean up any of the cuts which might require information technology because you're going to utilize this stringer as a template to salve marking out other stringers from scratch.

Test the stringer out where the stairs volition become to brand sure it volition fit. Remember that the superlative riser will be the correct acme only when the treads get on. If it's right you tin so replicate the stringer by laying it on pinnacle of the next pieces of lumber and tracing it. When you lot cut out a series of stringers you tin line them up and ensure that they are all accurate before installing.

Code compliance

Before you plan your project take a look at your local building codes and brand sure yous comply or exceed minimum expectations. Here are some full general guidelines. Generally forest stringers can be spaced autonomously past code a maximum of ii′-eleven″ in single dwelling units, unless a riser supports the front end of the treads in which example it'southward 3′-11." Mostly 2x lumber treads with no riser (actual thickness of ane-1/2″) will allow for the spacing mentioned in a higher place, however if a five/4″ tread (bodily thickness of 1″) is used and the distance betwixt stringers is greater than two′ 5-1/2″ then a riser must exist used to increase the strength at the leading edge of the tread. Tread depth limits are between nine-1/4″ and 14″ and riser limits are between 4-7/8″ and 7-7/eight." The maximum depth of overhang on the leading edge of the stair tread is one″. Code limits allow yous to customize stairs for different situations that will ensure they remain safe and functional.

Footstep on up

While it may seem like a bit of a process with a number of decisions to make along the way, once you do this a couple of times information technology's actually quite elementary and very rewarding. To walk smoothly and safely from 1 level to another on a set up of stairs yous have created will feel not bad and volition heighten your connectedness to your entry or backyard immeasurably.