How to Build Redwood Spa Steps

How to Build Redwood Spa Steps

After our manufactured spa steps broke, I did a quick search on the Internet looking for a relatively simple design to build steps, accompanied by photos and a clear explanation. Although I found one later that I would have considered, I became impatient and decided to sketch out a simple design myself. Then I went to Lowes to get some pressure-treated lumber. Not finding the 8-inch width I wanted in the treated lumber, I ended up buying redwood. My wife and I are very pleased with the result, so I am glad they didn't have the 8-inch treated wood.

This article shows how I originally built these steps in May, 2013. Following that description, I have added a new section showing how I added a handrail to those original steps in March, 2017.

Following that is a short section showing the design extended to three steps using Google SketchUp, a 3D Modeling App.

New Design Variation

At the end of the article is a Lessons Learned section, which also has photos of a new, smaller (meaning not extra wide and not extra deep, as were the original) set of steps. The new steps were also built in March, 2017, using an improved design. More photos and details of this alternate design are available in a related article through a link following the Lessons Learned section.

As a general rule, it is best to measure everything and avoid assumptions. Even though you try to pick out the straightest boards when shopping, there are usually slight deviations even in a three-foot length. And across four boards, those slight deviations can add up and play havoc with theoretical calculations.

  1. First I laid all four board sections for the tops of the two steps side by side and measured the total width to be 28 ¾ inches.
  2. Then I cut the two bottom 2x4's to that length.
  3. All boards were cut to length and laid out to confirm fit prior to assembly. Width and height are about the same as the old steps, but each step is four inches deeper. This makes a much more stable platform from which to negotiate spa entry and exit, especially if someone has balance or leg problems.

This design is fairly simple and looks good (I think) with redwood. With pressure treated wood, it might not look as good. I was trying to make efficient use of the four boards, so there are some gaps in the sides. These gaps are actually an improvement over the old factory-made steps, because leaves and other things would blow underneath the steps and become trapped very easily. It was hard to get the stuff out even with a leaf blower without moving the steps. The new steps have passed the leaf blower test.

Materials List

I had some spar varnish left over from another project. A quart (Lowes Item #68797) will be more than enough and should cost about $15.00 including sales tax.

Lowes Part #DescriptionQtyUnit PriceTotal


2x8x8 top choice redwood





2x4x8 top choice redwood





9x2-1/2-in. red decking screws

1 lb.



Sales Tax




About Board Dimensions

Dimensional lumber is specified in three dimensions, in units of inches x inches x feet, where the standard inch values are nominal.

For the dimensions specified in inches, the actual dimension will usually be about one half inch less than the corresponding nominal value. The dimension specified in feet should be accurate.

Finished dimensions

Width of both steps

36 inches

Depth of both steps

14 1/4 inches

Height of lower step

7 inches

Height of upper step

13 3/4 inches

Table of cuts

Length (inches)Number of 2x8 piecesNumber of 2x4 pieces



9 1/4



2 3/4



28 3/4


14 3/8


I didn't want to drag my table saw out of the shed, so I did all my cuts with a circular saw. It would be easier to get uniform heights for each set of vertical boards by using a table saw with a fence set for each height, six cuts at 9 ¼ in. and six at 2 ¾ in.

Remember to take into account that a rotating power blade will tend to chip and tear on one side of the board. The circular saw affects the top side of the board, so you will want to mark the side of the board that will not be showing, which is generally the bottom side. Then you will cut the boards with the good side down.

Table saws are the opposite, because the blade is rotating up through the table. So you will want to mark the top sides of the boards (or the sides you are planning to show on the outside for the vertical boards) and cut them good side up. The other thing you can do with a table saw is drop the blade so only an eighth of an inch of the blade is above the table, score the bottom of the board, and then raise the blade back up to finish the cut. The angle between the saw teeth and the board during the shallow cut is much less likely to chip the board.

If you want your steps a bit higher, just increase these heights accordingly. For example, if you want your lower step to end up 7 ½ in. high instead of 7 in. even, then cut the vertical boards to have a height of 3 ¼ in. instead of 2 ¾. To obtain a final height of 15 inches for the upper step instead of 13 ¾, cut the vertical boards to be 10 ½ inch instead of 9 ¼.

Remember, safety first! Always use safety glasses or goggles. Whether you get texts, phone calls, or visitors, when a power blade is in use, do not lose focus on what you are doing. Finish your cut, and then give the person your undivided attention only when it is safe to do so.

  1. Assemble each riser by attaching short vertical boards to the long bottom 2x4.
  2. Then attach the top, 14 3/8 inch 2x4 for that (lower) step.
  3. Next attach one of the long vertical boards with a couple of screws to both the short vertical board and to the bottom 2x4.
  4. Finally attach the other two long vertical boards to the bottom 2x4 and attach the top 2x4 for the upper step.
  5. Repeat for the other riser.

When both risers are assembled, it is time to set them up, fit the four boards for the steps, square up the assembly, and fasten with deck screws. I took everything into our den and used the ceramic tile pattern to visually square everything up.

  1. First, I attached one screw in each corner, starting in the left rear and going clockwise to each successive corner of the whole assembly, rechecking everything before driving in the next screw.
  2. After all four corner screws were driven, five more screws were driven in on each side of each step. If I had it to do over, I would have lined up the screws better, so you might want to use a straightedge when starting these screws. I used a hammer to tap them into place before using the drill to drive them in.

Photos of the Assembly Process

The gloss spar varnish was left from another project and was applied to the steps using a 1-inch brush and a small roller, just two or three inches wide. If I had it to do over, I would have made all the cuts, then varnished all sides of all the board sections, and then assembled them. I varnished after assembly, and found that there are many joints and gaps to work the paint brush around.

After varnishing

Laying out, measuring, and marking the handrail boards for cutting

First, decide how much to angle the handrail by either measuring or calculating the angle at which the steps are rising.

I used the True Angle Tool to measure the angle. I used a straight length of board placed along the top-front of the steps to make the slope clear enough to measure with the tool.

This is the True Angle Tool I bought years ago to measure wall angles for installing baseboard.

Calculating the Slope

The way to get the angle of the slope without measurement is to do a little math. The slope is defined as the rise over the run, which is simply the step height divided by the step depth, front to back. For example, in my case, each step is about 7 inches high by 15 inches deep. So the slope is 7/15 = 0.46667.

This slope is also the tangent of the angle formed between the tops of the steps and the surface on which the steps are resting. The inverse of the tangent function is the arctangent, typically abbreviated “arctan”.

In the old days (I won't say how old), we would look for this value in a trigonometry table, or find it using one of the nicer slide rules. Nowadays, you can use a handheld calculator with trig functions, a trig calculator app on your smartphone, or even a search engine query.

Decide Your Handrail's Height

Next, decide how high you want the handrail. Imagine what height it would be most convenient to grab, and measure from there to the floor with a tape measure. Measure this height at the position where you plan to put the shorter post, so you can use the low end of this post as a starting point for measuring and marking your cuts.

Lay out the boards, measure, and mark your cuts

See the following photos for how to lay everything out to mark your cuts. During the project, I cut the posts so that the second post was 7 inches longer than the first. After attaching the first post to the handrail board, I slid the second post forward or back until it fit against the rail correctly with both posts resting on the floor.

But one of the design improvements I was already planning to make in my next set of steps was to overlap each riser by an inch or two. Overlapping by exactly 1 ½ inch would make it possible to saw out a notch in each step so that the outside surface of the post, after being placed within the notch, is flush with the edge of the step. But that would require a way to precisely determine where to put the two notches. The photos and captions below show how I conceived this procedure should look. The leftover boards I used in these photos are not the same size as the boards I actually used in the project.

I used a rectangular patio table for a little extra help keeping the two “post” boards square with the “floor”. But this was primarily accomplished by using the carpenter's square as shown. If the table were unavailable, I would have used the combination square to help square up the second post.

Layout How-To Photos

Layout Photo Comments

Use the rule along the bottom of the carpenter's square to create the exact gap you want between the posts. Write this distance down and note which edges of the boards you are measuring between.

The post spacing in these example photos is not intended to be copied. My posts ended up being about 19 1/2 inches, measured from the leading edge of the front post to the trailing edge of the back post. These steps are about 28 inches in total depth. If your steps are 22 inches in total, then you would probably be looking at around 13 or 14 inches.

I marked this board at 37 inches at the point that will be the posts' lowest edge. The rail will add another 1 ½ inches, for a total height of 38 ½ inches.

Making angle cuts on a table saw

The photo above shows a pencil line marked on the board. Close one eye and make sure you are looking straight into the saw blade with the pencil line positioned where the blade will obliterate it. I like to put the edge of the blade on the edge of the pencil line. The blade is wider than the pencil line, so you want the other edge of the blade on the side of the board that is being cut away from the piece you are working on. I make my pencil marks with this in mind, so that the one edge of the mark is bounding but not overlapping the measured length. If you are not careful, you will end up with pieces that are too short by half the width of the saw blade. Not a big deal when cutting posts for a handrail, but for other cuts, that error could be significant.

Prepare the Handrail

When doing the layout to mark the post cuts, measure the handrail board so that it is long enough to extend beyond each post by four or five inches. This will make it easy to get a handhold on either end of the rail without jamming one's fingers into the post.

If you have a mechanical cover lifter, be careful to not let the top end of the handrail extend out over the hot tub, where it will interfere with opening and closing the hot tub cover. If you do want the rail to extend over your hot tub, then be prepared to move the rail-attached side of the steps back and forth a few inches each time you open or close the lid. If your lid just slides out of the way onto a neighboring deck, then consider whether the handrail will interfere with that if positioned where you think you want it.

My handrail ended up being a little shorter than the total depth of the stairs. After cutting a 2x4 to the desired length, I decided to rip-cut it down to a width of 2 1/16 inches to make it easier to get a handhold.

Notice the push stick on the right side of the table saw. This one came with my Craftsman table saw. There are better, safer options available that you can either make yourself, or buy locally or online. These give you more control of your work piece and help prevent kickback, and, like the basic push stick, keep your hands away from the saw blade.

I used sandpaper to round off all the handrail's edges and corners. I started with coarse (60) paper, then medium (100 or 120), and finished with a fine grit (220). I also used a power sander on the handrail ends to get them as smooth as possible.

I used the same kind of deck screws for the handrail as for building the steps, but you might want to go up to 3 inch screws for attaching the posts to the side of the steps. The following photos show the screw locations.


If you are planning to build this design for use in direct sunlight, you may want to read the follow-up report linked below. The most important lesson I learned is that the steps will need to be re-varnished often, perhaps every six months, in order to prevent excessive fading. Re-varnishing too late will result in the steps being darker when the varnish is eventually applied. Of course, some people might prefer the darker finish anyway.

New Design Variation

The new design has two 30 inch wide steps that are each 11 inches deep and rise 7 inches. Most people do not need the extra width and depth of the original design. I also wanted to have a continuous board face showing on the front side of the risers. This looks better than the board ends, especially as the boards age. All cuts were made with a table saw or chop saw. No circular saw cuts.

Tread boards overlap risers by 1 ½ inch on each side. Holes for each screw in the steps were carefully measured to form straight lines and drilled before installing screws to prevent board splitting at the edges.

After a second reader asked me about a three tier design, I downloaded Google SketchUp, a 3D Modeling App, to see if I could use it to quickly extend the two step design to three steps. The first day using the app I was able to come up with a rough design.

After watching a few instructional videos and reading a couple of beginner articles, I was able to refine the crudely fitted joints in my original model and add the side-facing vertical boards that I had initially left out of the risers. For comparison, I used vertical 2x4's on the right hand riser, and 2x6's on the left. SketchUp allowed me to easily rotate the model, hide the riser on the opposite side, and print a 2D JPEG of each view.

I am including three views of the basic three step model, a fourth view showing the riser with vertical side-facing 2x4's added, and one last view showing the riser with vertical 2x6's added. Note that one of the vertical 2x4's from the basic model had to be removed from under the highest step to make room for the 2x6.

Basic design extended to three steps

Dimensions and Permitting Requirements

Each step is 30 inches wide and 11 inches deep. If you need steps wider than 30 inches, you should consider adding a third riser in the middle. If the project becomes too large, it stops being a set of portable steps and becomes a permanent structure. In this case, you should check local building codes and permitting requirements. With increasing height and weight I would expect an increasing need for cross-bracing or anchoring to some other structure.

The steps overlap the risers by 1 1/2 inch on each side. The distance from the ground to the top of the first step is 7 inches, the second is 14, and the third is 21. Figure the actual width of the boards to be 1 1/2 inch and subtract as needed to get the exact length of each board in the diagram. The lengths in inches I calculated to go into one riser are 30, 19 1/2, 18, 16 1/2 (two boards), 8, 5 1/2, and 2 1/2 (two boards). Same for the other riser, of course.

The 2x6's are actually 5 1/2 inches wide and cut to 30 inch lengths.

Watch the video: How to Build Steps or Stairs For A Tiny House Deck (May 2021).