Fence boards cup in or cup out

[Bill Dufour]

I am rebuilding my fence. I am putting a tongue and groove on each board. I am using four screws per board. two top two bottom. Should I put the cupped board cup in or cup out? I have been putting them cup down to the 2x4 since that is the way they referenced to the shaper table.
There was a original 4" picket fence that 15 years ago they nailed taller boards to. The 70 year old redwood is in better shape then the 15 year old second growth stuff.
The picket fence was a weird build they laid a 2x4 flat on the ground and nailed the pickets to that with a standard horizontal 2x4 almost at the top. 4x4 posts every eight feet like normal.
Bil lD

[Andy D Jones]

The same way you cut the T&G.

Depending on how tight the T&G fit is (it should not be very tight for a fence, I should think), you may want to take care not flattening out the cup too much when you screw them to the fence rails.

-- Andy - Arlington TX

[Mel Fulks]

With slab cut conifers I make the face side the "bark side" . The grain won't pop up into razor blade like layers.

[Erik Loza]

Thought: Even with that many fasteners, will you not induce bowing by having them fitted as tightly as T&G once the water/sun/etc. goes to work on them?

Erik

[Eric Schmid]

Erik makes a good point. Whenever I build T&G panels for exterior use they get captured in “dados” allowing for movement. Sometimes these dados are built up and sometimes they are cut in. Either way the fasteners don’t go into the fence board.

Screws would be my last choice for fence boards if attaching directly to stringers. Always stainless, sometimes staples other times siding nails. No matter how the boards are fastened, they are going to move even if that means they split to do it.

As for cup in or out, I usually pick the best side out. Best side includes looking for grain lifting as Mel describes.

[Philipp Jaindl]

For Fenceboards its probably less critical but usually you wana put the Hollow towards whatever you're screwing/Nailing them to. That way they wont try to push the Nails/Screws back out when they really start to warp and bow after years and potentially split the wood or snap the rusted screws off (if you dont use Stainless), though with T&G thats less of a concern. And yes Absolutely do yourself the favour and use Stainless Screws, it will save you a lot of hassle when you have to replace something and dont find every other screw snapping off.

[Bill Dufour]

I should,have said it is wedge tongue and groove with some gap so there is a little room to move. I did about 75 feet of fence 10 years ago and only two boards split. Yes stainless screws Via ebay from Hawaii. I did some 45 feet this way at a previous house 30 years ago. I will have to check it out but I think it looks could from the street at 5mph.
To save a lot of work I put tongues on half the boards and grooves on the other half.
Bil lD

[Erik Loza]

And yes Absolutely do yourself the favour and use Stainless Screws, it will save you a lot of hassle when you have to replace something and dont find every other screw snapping off.

I was doing an outdoor project not too long ago with a mix of local cedar and some hardwood. Started with stainless Spax screws. Snapped off about every third one on the way in (weird angles, couldn't really pre-drill). Finished the project with coated screws and no issues. Stainless is probably fine for thin boards into softwood posts but for anything else, I'm sticking with coated. Unless someone was inclined to pre-drill every hole. Just my experience.

Erik