I need help w/ my fence

[happy hopping]

https://imgur.com/NAXKrrJ

at the middle of these fence board, I am about to install a 2x4 x 8ft at the very top (and at the bottom), and I highlight it in black at the photo. As I will be putting new fence boards just like the way it is at the left & right of the photo.

So that will create a gap BEHIND that 2x4 x 8 ft. I want to fill up that gap, level it, I need a space filler. Now supposedly, if I install a 2nd 2x4 x 8ft, that would somewhat do it, but w/ a 4 mm gap. I want the top totally fill up

What are the options? what can I do?

[prae]

rip something down on a tablesaw? I'm not sure I understand the question but at the end of the day it's a fence, not fine furniture. that shit is gonna move more than 4mm every freeze-thaw.

[The_Rural_Juror]

Guile flash kick > crappy table saw

[bookem]

Put the second 2x4 on top on the horizontal, instead of behind on the vertical.

[03ozwhip]

Suck it in from the top with screws....

[topmade]

Get 2x6x8 and rip it to the width you need. Or better yet get a 2x8 or 2x10 to get two boards out of one piece and it might be cheaper that way. When you are all done, take a circular saw and run it over the top of all to even it all out, that's just annoying to look at. But really, a 4mm gap on a fence nobody will notice what so ever.

[The_Rural_Juror]

I am going to be THAT guy and suggest that the awful staining job is much more noticeable than the 4mm gap.

[triplep]

How would you only get a 4mm gap if you lay a 2nd 2x4 on it? A 2x4 is 1.5" x 3.5", so if you put two together, you'd only get to 3", so you'd be .5" short? Was the plan to have the fence boards sunk in, or are you getting them flush?

Wouldn't it just be easier to put the 2x4 so the 3.5" side matches the fence post (I assume it is 3.5") as well. So lay it flat on the fat side, as opposed to laying it flat on the skinny side? That should get ride of any gap issues you have. If you are worried about supporting the span, you could always put another 2x4 vertically so you make an I shape support, and that should hold up.....

[rx7boi]

Ask a Honda dealership to help you.