Building Simple Deck Handrails
With 2x4 Treated Lumber
Bruce W. Maki,
This mid-1970's house has a walk-out basement with a deck above.
But the deck needed handrails. It's an eight-foot drop to the
concrete below the deck, which sounds a bit dangerous.
||Two views of the house without handrails.
I thought it looked kind of bare... like a face without a
||This corner support post was not positioned the
same as the other corner... the base of this post was moved
out flush with the face of the deck and secured with a block
I removed the block and hammered the post back into the
proper (and plumb) position.
|The deck steps looked newer than the deck. These
were built incorrectly... the treads (the boards you
walk on) are supposed to protrude about one inch beyond the riser
(the vertical boards your toes kick).
||The framing below the deck. The joists are
2x10's spaced about 24 inches on center.
I made a quick CAD drawing of this handrail design to help me
keep track of dimensions. Maybe this will be useful to some readers.
The blue lines represent the intermediate posts. I don't show all of
the spindles in the frontal view.
I began this project in my workshop. I made initial measurements
of the spacing between the deck posts, and then I pre-assembled
sections of handrail about a half-inch longer than the measured
Why make the sections longer? Experience tells me that 1) Nothing
Ever Goes As Planned, and 2) it's much easier to cut a board shorter
than to correct a board that is too short.
Besides, the deck posts were badly warped and twisted, rather
out-of-plumb, and just not very precise. The way I deal with such
lack of precision is to make the pre-assembled sections a little
extra long and trim them to length prior to installation.
Also, before starting I gave all pieces of wood a quick sanding
with a random orbital sander. The instructions on the stain I used
insist on removing the "mill scale" with a light sanding.
This took about half an hour.
|Installing the first section (near the top of
the picture) was easy because it was a simple run between the
corner post and the post nailed to the wall (not visible in
The other sections were more challenging because they had
to be connected to intermediate posts.
||This is one of two posts that I cut and primed
in my shop. The notch is easy to cut with a circular saw.
Cutting this notch in a similar post can be seen in this
|I inserted the post (red arrow) into the hole in
That diagonal piece of wood was necessary to straighten the
outer pair of joists, which had warped over the years. Without
straightening, the post would lean badly.
A Common Problem:
The diagonal block of wood is basically half of the
old-fashioned cross-bracing between joists. Cross bracing can
be a pain to cut because of the odd angles. It's more common
(and easier) to use solid wood blocking made from the same
material as the joists (2x10 in this case), but I didn't have
any large lumber with me, and it's too far into town to
justify driving to a lumberyard.
To force the double 2x10 outer joist into a plumb position,
I wedged a long 2x4 between the joist and the concrete slab
below, and hammered the base of the 2x4 until the post was
plumb. Ah... the joys of working with wood... nothing's ever
One cheap and quick solution is to shim the post where it
attaches to the joists, but this would not solve the problem
of the joists being too flexible, and the entire railing would
||I used a Quick Grip clamp as a "stop
block" to hold the section of railing in position. This
also kept the railing from falling off the deck.
|The first connection I made was between the
railing and the post.
At the top I pre-drilled a hole and drove a 3" deck
screw into the post.
||On the lower horizontal 2x4 I drove two deck
screws into the post.
At this point the left end of the railing is loosely
held to the corner post, and the white post is only
clamped to the joist.
Note how the railing is resting on blocks of wood (with a
shim to help make the section level).
Note that the face of the horizontal 2x4 is set back about
5/16" from the face of the post. This setback makes the railing
assembly centered relative to the post.
With the railing attached to the intermediate post, I attached
the other end to the corner post, using the same method as the above
two pictures. Of course, I made sure the railing was level and plumb
before I attached it.
|Holding the intermediate post plumb, I attached
it to the joists with 4½ inch Simpson Strong-Drive lag
screws. These require a heavy-duty drill with a 3/8" hex
driver bit. Ordinary lag screws would work fine, but they
require more time.
Note the big washers. I always use large washers to spread
the clamping force over a larger area. Without washers the
screw heads tend to sink in and crush the wood fibers, which
(I believe) causes the posts to loosen over time.
Also note the pieces of OSB behind the post. I needed these
because I made a mistake in measuring and cut the post notches too
deep. This is one drawback of working away from the job site... it's
harder to check your measurements.
To recap my railing installation approach:
- I measured the distance from the corner post to the end
of the first railing section.
- I marked the post location on the deck boards, by
tracing a scrap of 4x4.
- I cut the deck boards with a Sawzall, making the hole a
little bigger than the post.
- I inserted the pre-cut intermediate deck post and held
it loosely in place with Quick-Grip clamps.
- I placed the section of handrail on 3" support
blocks and secured the railing to the loosely-clamped intermediate
- I adjusted the railing to be level and plumb.
- I attached the other end of the railing to the corner
post (or to the previously installed intermediate post).
- Holding the new intermediate post plumb, I bolted it
securely with lag screws.
Keep in mind that there are many ways to install
handrails... this is just one method that works well with
pre-assembled sections of railing.
||I installed the third and fourth sections of
handrail in the same manner.
|The connection between the railings and the
intermediate posts. I also installed a screw in the underside
of these top horizontal boards.
||The lower connections are not my favorite
approach, because I'm not too crazy about visible fasteners,
but this railing is a more economical approach.
One alternative is to install metal angle clips to the
underside of the bottom rail, and screw these to the posts.
|After the handrail sections were installed I ran
the belt sander over the top to smooth out any protruding
spindles or other high spots. This tool (Sears Craftsman,
about $60) is worth it's weight in gold.
||I installed the top cap with 3" deck
screws. Since the total length of this front railing was
17'-5", I had to use two sections of top rail. I
bevel-cut the first section, which makes for a stronger and
|The second piece of top cap was also bevel-cut
to fit against the first piece. The junction is barely
Note in the picture above that there is a slight
"chamfer" or angled edge to the corners of the top cap. I
made this with the belt sander, and it took only a few minutes. This
reduces splinters and looks a bit nicer than the rounded edge that
comes with the lumber. Besides, the rounded corners are not always
the same radius on different boards, and this is a way to avoid that
||For no reason other than general laziness, I
chose to build the stair railing and the short flat railing at
The first step was to mark the location of the upper post
and cut the hole in the deck boards. The upper post was set to
its final height, but the lower post was left too long.
These deck posts did not need to be notched like the other
|To install the lower post, I removed part of a
I held the post in place with clamps and shimmed it plumb.
||I measured the "Nose Angle", or angle
that is formed by the edges of all the stair treads.
I laid a 4-foot level against the steps, then placed a
12-inch speed square on the angled level. Using a shorter
level (held perfectly horizontal) I read the angle on the
The nose angle was 34 degrees above horizontal.
Marking The Cut On The Lower Post:
I laid a long 2x4 on top of the upper post, and clamped it
to the lower post, guessing about the angle.
||Closer pictures of that.
|Using a speed square and a 2-foot level, I
measured the angle of the board. I moved the board until I got
the angle correct.
This is much easier to do with a helper holding and
adjusting the lower end of the board.
||When I had the board at the correct angle I
marked the line where the underside of the board
intersected the post.
This represents the top edge of the upper rail, and
the underside of the cap.
|I cut the top of the post on a miter saw and
then fastened the post to the stair stringers, using 4½ inch
||To measure the upper rail, I first screwed a
long 2x4 to the top of the lower post. This acts as a
temporary top cap, to help in measuring the rail beneath it.
Using a miter saw I cut the angle on the lower end of the
rail. In this case it was 34 degrees away from a
normal square cross-cut.
Then I placed the lower end of the rail against the lower
post and held the rail in place with a clamp.
|I marked the line where the face of the upper
post intersected the rail.
This cut was not exactly the 34 degree angle
I expected (of course)... because... it's wood... everything is warped and
||I cut the upper rail to length and installed it
with 3 inch deck screws.
One advantage of this technique is that it tends to make
the rail a tiny bit too long after the first cut. (If you
understand the geometry of triangles you'll understand
why...you are getting the hypotenuse of a long skinny right
triangle, when you want the long side)
But this just means that I have to make an extra cut to
make the rail to fit less tightly. I prefer it this
|I installed the top caps over the rails.
|I screwed the spindles into place.
I cut a pair of spacer blocks (red arrow) and held them in
place by just pushing on the spindle.
The spindles on the short horizontal railing had been pre-cut in
my shop. I intentionally left several spindles extra-long, knowing
that the sloping handrails would need longer spindles.
||For the sloping handrails, I first determined
the location of the upper-most spindle, then I cut the spindle
to length. This meant that the top had to be cut on an angle
on the miter saw. Again, this angled cut was 34 degrees from a
normal square cut.
Once the first spindle was cut and checked, I cut the
remaining spindles to the same length. To install the spindles
I held spacer blocks (one upper and one lower) in place with
clamps while driving in 2½ inch deck screws.
|The completed railing.
||I used the belt sander to chamfer the edges of
the top cap, and to clip off the protruding tip of the angled
Note: In some areas building
codes require a "graspable" railing on stairs, so
this 2x4 top cap may not be acceptable by itself. I have seen
projects where the builder had to install a narrower piece of wood
on top of a railing like this. Ask your local Building Department
for a list of suitable materials that meet this
After all the carpentry was completed I finished the railings in
the following manner:
- I spot-primed all the knots with Zinsser's BIN Sealer, which
helps prevent the sap from bleeding through the finish.
- I primed the wood with Zinsser's Cover Stain oil-based primer.
- I coated the wood with Rubbol DEK solid tone stain by Sikkens.
This is an excellent oil-based coating that appears to be the
same as paint, but has less tendency to peel. It is supposed to
wear away slowly without peeling. The primary benefit is that 5
to 10 years later when it's time to repaint, scraping loose
paint and re-priming won't be necessary. All it needs is a
power-washing and single recoating. This product isn't cheap
(about $40 a gallon) but it performs well. I used about half a
gallon on this railing.
|I think the house looks better with railings.
||The house has brown-stained rough-sawn T1-11
plywood siding, which gives it a rustic appearance that is
hard to capture in pictures.
|Railings add a small amount of privacy to a deck
or porch... plus a feeling of security!
||In these pictures the railing seems to have a sleek
contemporary appearance, but the small photos can be
|Much of the rough wood texture shows through the
solid-tone stain, although the pictures don't capture the
texture very well.
In some pieces of wood the grain is distinctly visible through
the coating, because the smooth-planed lumber shrank after milling,
leaving bands of high and low material.
The material costs for this railing, about 29 lineal feet, was
around $120, not including the paint. While this railing was built
with ordinary pressure-treated Southern Yellow Pine lumber, a
smoother appearance can be obtained with various types of cedar.
- Cordless Drill/Drivers
- Basic Carpentry Tools
- Quick-Grip Clamps
- Miter Saw
- Reciprocating Saw
- Belt Sander
- Random Orbital Sander
- Painting Tools
- Pressure Treated Lumber,
- Pressure Treated 4x4 Posts
- Deck Spindles
- 2½", 3" Deck
Do you like this article ?
Back To Top
Read our Disclaimer.