Can you install decking boards with grooves up?

[Farleys]

Been meaning to post this for a while. A few weeks ago I was at a mates place and noticed his deck had decking boards with the grooves. I told him I thought they were supposed to face down. He said they were meant to be that way so you don't slip, which didn't sound right. Is it just preferance or are you definitely meant to install decking boards with the grooves on the underside facing down?

[Jackson]

@Farleys - you're both kinda right.

The grooves are non-slip. You'll see a lot of people use grooves if they have a ramp or steps off their deck. However, the grooves are actually there for air circulation underneath the boards and manufacturers recommend you install your boards groove-side down.

I'd just say go with whatever you think looks better.

[AHoy]

Nah, it should be grooves down. No debate. You might even void the manufacturer's warranty if you install them upside down. If you need a non-slip surface, then use an appropriate sealant or textured strips. The grooves should be face down as they are there for airflow and to stop moisture build up. If they are face up they will soon be full of grit and grime and algae etc and will become even more slippery. 

[Jackson]

Well @AHoy - Workshop is a discussion forum so I'd say debate is probably considered mandatory.

Just for some anecdotal evidence (the best kind), my brother-in-law (carpenter) has his ramp groove-side up and it isn't slippery at all. He has had no issues with rot or algae, and older relatives enjoy the extra grip. 

To your point about warranty, you probably void the warranty by not having it installed by a licensed carpenter too. You probably void the warranty by not using the recommended products to clean and oil it. You probably void the warranty by not cleaning it weekly and oiling it twice a year. I've never even heard of anyone using a manafacturers warranty on a deck to be honest. I'd consider that point pretty moot.

I'm sure you'll use some Google-fu to prove me wrong but I think you're just a bit too much of a by-the-book type of character, @AHoy. You sound like the type of bloke who goes to parties and makes sure that there are an adequate amount of fire exits. I stand by what I said, do what you think looks better and make sure you look after it. You'll be fine.

For what it's worth, I agree that smooth-side up looks better.

[AHoy]

Ha! I don't know about fire exits, but I do like following a good instruction manual! Sorry Jackson, I didn't mean to stifle discussion.  Your point about ramps is a good one, that's the only application grooves up should be considered. Water can't pool in the grooves obviously if there's a slope. 

[Kermit]

You are both wrong. Everyone knows you're supposed to lay the boards on their edge. Sure, you might use more timber but you get additional height. 

[Jackson]

That sounds like a great conversation starter, @Kermit!

[Andy_Mann]

You guys've need to get out more if you're getting niggly about debate etiquette, imagine being a NZer, & asking an Aussie Bunnings staff member about a deck extension.

[Jackson]

We're just having a nice, robust discussion, @Andy_Mann. I'm surprised you haven't weighed in with an opinion yet. It's not like you to sit on the fence 

[Andy_Mann]

@Jackson, just for you. 

I reckon the grooves are the dumbest idea ever, they're only there to get blokes fuss'n about it,

I propose that only grooveless decking be sold in future, & that all existing grooved stock be planed flat, before sale.

Preserve the planks with old sump oil, & sweep building sand over the top surface while the oil's still tacky for slip protection.

I hope this helps.