Looking for input: fence design

[Jeff Hallam]

I know this isn't exactly fine woodwork but I will soon be building a privacy fence on our sloped lot and I am trying to find the balance between good construction and cost. My question to you folks is do I need the middle rail in this design or can I save money and just have the top and bottom supports? As you can see, there would be about 5' of unsupported fence board if I omitted it. The difference is about $200 in the overall cost. I appreciate the input from your experiences.

Jeff

fence mockup on slope.jpg
fence perspective.jpg

[Angie Orfanedes]

Guess it depends what the fencing material is. I have done it both ways with rough sawn pine as well as treated lumber. Without the center support you risk the boards developing "innies" and "outies" as they cure in the weather. Then again those fences were not painted either.

[Sam Yerardi]

Angie is right. One thing that might help your decision is based on how much fence you are talking about (in terms of length). Consider your time & materials for repairing the fence later if you don't provide the middle support. Adding the extra $200 starts to look a bit more appealing.

[Sam Layton]

Hi Jeff,

I have done it both ways. Now, I only will use 3 rails. It really makes a difference.

Sam

[Walt Caza]

Hi Jeff,
Sorry for coming late to this thread, just saw it now.(at 2am!)
We often ask advice, when we already know the answer, but wish we didn't...
Yes, triple is better.
Might I suggest that rather than considering the cost of adding the middle rail,
instead you consider the cost of Not adding the middle rail? (twisty?)

I build my fence at least 7 years ago.(maybe 11?)
Not sure when, really.
But I am sure it is behaving itself nicely.

Like your proposed design, I went with 6 foot sections.
Took the best 6 feet out of each 8 foot rail, for the 4 rails per section.
Also uses more posts in total. Less efficient, to be sure, but better structure.

Wood is always moving. Moisture in and out.
Especially outdoors in the elements.

Ya, it's not exactly fine woodworking...
but I took pride in mine and built it as well as I could...
and it still looks good after all these years.
I used a level to mount every slat, and drove screws - no nails.

good luck with your project,
be sure to give us a peek,
be well,
Walt

ps The T'd pair of top rails prevents water for entering the top end of the slats.
I took the time to stain each slat on all six sides before installing.

Slow ya, but worked out good. This is still the original stain, taken May 2006 -2 yrs ago.
I am do for a re-stain I guess...

[Jeff Hallam]

Thanks for the replies everyone. You confirmed my hunch and I have elected to go with the three rails. The posts and top rail are in and i'm just waiting for a break in the weather to keep working outside (of course its beautiful all week and rainy on the weekends). To answer the question, I have about 290 feet of fencing to do.

I too am using screws vice nails and I will predrill the fence boards so that they don't split when driving the screws.

My next design questions will be to think about the two gates and what hardware will look and function properly. I can say that I was never bothered by having a sloped backyard until this fence project. It certainly slows the process as I will need to cut each fence board a different length as I proceed down the hill.

[Walt Caza]

Hi Jeff,
Depending how wet your treated lumber is...
you should be able to drive your screws without having to predrill.
That's alot of screws! And that should be a good time saver.

Certainly try a few, to see if you can get away with skipping a step.
You have plenty of work to do already!
I drove all of my screws without predrilling, and had no trouble at all.

Good luck with your slope,
Walt

[Jeff Hallam]

Hmmm, you're right that would save a lot of time. Perhaps I will only predrill the two that go in near the end of the board (screwed to the top rail). That means only 2 out of 6 screws are predrilled for each board.

Walt, is your fence cedar or just stained to look like it? Do you have any splitting after all these years at the top end of the fence boards?

[Walt Caza]

Hi Jeff,
I think you will find there is no need to predrill any of the screws.
Here is a pic I just took now...
of my screw pattern at the top of each slat into the rail.
fence-pattern.jpg

Since you are fastening to a full width of 2x4, there is enough room
to stay away from the slat end, and avoid inviting splits.
I just walked my fence, and saw no splits at those screws.
I bet you can skip the predrill time and tool changes.

Nope, not spendy cedar, just CCA pressure treated lumber.
I used Sico Canada Formula 77 treated wood protector, decks and fences - colour Redwood.
It has proven quite durable.
While it could certainly use a re-coat now...
it has held up much longer than I expected.

Something that is seldom talked about... is mill glaze.(search the net)
If you're gonna put anything on top of PT lumber,
do an absorption test first.
Put a few drops of water on your wood, and see if it absorbs.
Mill glaze can interfere with wood taking in any finish.
Some say to age new PT a while before putting anything on it, for that reason.

Also common is the belief that PT is ready to face the outdoors.
The old recipe PT used CCA - copper, chromium, arsenic, which is
now outlawed in Canada. (Jan 2004)

In CCA, the copper is the primary fungicide, the arsenic is a secondary fungicide and an insecticide, and
the chromium is a fixative which also provides some UV resistance.
CCA is applied to wood in a water solution and chemically reacts with the wood to form a virtually insoluble precipitate.

While it helps to have fungicide and insecticide on outdoor wood,
my research back then taught me that they offer little or no protection
against sun and water, which are also huge threats to the longevity of your outdoor project.
That is why I spent time, effort and money on that stain/protector. (hand brushed, many gallons)
Also, the colour was a pleasing alternative to the ubiquitous ugly PT green.

It was the first and only fence I have built... I made a spacer for my 2" slat gaps.
Pinch it between the last slat, and the next...
hold the level against the new next,
swing it to plumb and drive a screw. (pic is 1.75", but I used 2" spacer & gaps)
slat-spacer.jpg

Good luck with it,
it's a sore back project, to be sure.
Walt

ps Bonus tip: I see many yards with 4x4 posts standing too tall, that were never trimmed.
I tried two passes with circular saw and also sawzall to trim the posts.
Heavy, dangerous, and tricky to do a nice job of it overhead.
I found a 15" handsaw, with the triple edge tooth to cut them quick & true.

[Jeff Hallam]

I really appreciate you taking the time to post those details Walt. I'm happy to skip the predrilling after seeing your results. Also taking to heart your comment about trimming the posts. I was thinking reciprocating saw or circular saw but I concede that I don't look forward to wielding one from the top of a ladder.

You say you used a 2" spacer, I had planned on something a little wider, namely a 4" gap. I even made different sketchup models of the fence with different gaps to compare how much privacy they afforded when looking from the street view versus the extra cost, wind resistance, and weight of a smaller gap.

The tricky thing for me will be making a consistent gap (close to 4") as the spacing of every posts on each section is different (I'm not exaggerating!). I created an excel sheet that takes in the inside post-to-post measurement and the "desired" spacing and spits out the actual spacing that I would need to use in order to use a round number of fence boards. It is difficult to explain I think, but the end result should be the best compromise that I can think of. The other option would be to use a consistent spacer and end up ripping the last fence board to compensate.

If you're interested in taking a look at the spreadsheet I can post a link.

Cheers,

Jeff

[Walt Caza]

Good Show Jeff,
Sounds like you are doing your best to think everything through...

Friendly reminder, the 1x6 boards you buy, mine were 6 foot long,
will vary in width.
Mine averaged 5.25". Some were less, many were nearly 5.5 inch.
As you mount slats approaching your next 4x4 post,
you proceed minding your gaps and making adjustments to help it work out.
I layed the last few slats against a rail, to get a sneak preview of
the gaps needed for all of them to play nice.

In spots where that did not work, in a couple spots I added slim ripped slats against the 4x4 post.
Such as 1.5" wide x 5.25 x 6 foot high.
I filled the bare minimum that way, preferring full slats when possible.

Spreadsheet is cool, but it does not realize that your slat widths vary!
What width average width of slat did you plug in?

My 2" gaps minimized the diagonal viewing of a public sidewalk on my corner lot.
You raise a good point, when the wind roars, you want it to pass through...

I should think 4" gap will work fine, but another reminder...
not only must you monitor slat gaps on this side you are working,
but also on the other side so that they cooperate nicely.
Cumbersome to type, not a big deal to execute...
just another detail to stay mindful of as you mount slats.

Ya, section widths vary but you will dance around that just fine.

I had great luck with a 15" agressive tooth Stanley handsaw on the posts.
Surprised I tried it, and more surprised that it worked great!
The posts look daunting for handsaw, but cut quick and easy to a line.

eager to see your results down the road,
be well,
Walt

ps I was just blasted by all 9 of our Canadian Snowbird jets flying in tight formation,
leaving my city after our 'big' airshow. Startled me nicely and roared huge overhead! cool

[Jeff Hallam]

Well, i've been plugging away at the fence and I thought I would post some progress pics. I started trimming the fence posts yesterday. Ended up getting a sawzall as I found that although a handsaw worked well, it was uncomfortable and difficult to saw sideways and my arms would have fallen off before I finished cutting the 40 posts.