I just built a deck using 1x4 cambara decking. From what I learned in my research, you should provide good ventilation beneath the decking and also provide 3/16" spacing between the boards. Furthermore, I would highly recommend prefinishing the decking on all 4 sides, or buy pre-finished stock. Also seal the ends as you cut and install the decking. I used Cabot's Australian Timber Oil, and have heard that Messmers' UV is a good product as well. Call Coastal Forest Products, Bedford NH 800-932-9663 for more info. They were the distibutor of the cambara I bought and answered some of my questions.
Good luck.

Kai,
3/16" spacing is a bad idea. after that wood shrinks, you're gonna fall through the gaps. you don't see it now, but wait till the summer comes, and the sun is shining.

Prefinishing the top is another bad idea...oxymoronic. there's something wrong with a finish at the start.

steve

mig1,
In my experience, many carpenters who seem to be competent, can often times be negligent when it comes to designing things in a way that will stand up to the elements. This is something I find to be the rule rather than the exception, especially among deck builders.

In this case it is not problematic to prefinish the decking, as Steve seems to think, because the timber oil is a penetrating oil and leaves a durable surface that is forgiving of any abrasive treatment that might take place during installation (it would take a lot to screw it up). Of course the most important reason for doing this is to treat the underside before you put it down -- you could leave the top side unfinished until you have finished installing the decking, but it's not necessary, I assure you. (I would buy the prefinished cambara, it's worth it.)

As for the 3/16" spacing, I was reiterating what I had read in the literature put out by CECCO Trading, Inc. ( ironwoods.com, 414-455-8989 ), who put out this product ( They actually recommend 1/4" for 5/4x6). The reason for the larger than usual spacing is the need for ventilation which is vital for the longevity of this product. I should also add that it is really important to have air circulating under the deck, up through the gapping, so you really should not have the deck completely enclosed at the joist ends. Cambara is not highly rot resistant, so it does require proper installation and maintenance.

Kai

I have noticed that some people prove the old saying true>> Them that can Do,Them that cant teachUsing any material that is not highly rot resistant as decking is a total waste of time and money, a coat of finish on the bottom side is not going to change the nature of the wood, any more than using hemlock as decking and hoping a thin coat of anything is going to help it not to rot.

A person is looking for Cross Vintalation under the frame of a deck,not venting thru the gaps. The air moves under the frame in and out this moves moisture out and helps equal out the temp underneith and I assure you helps keep down the mold.

Pre finish all together is not a good idea for decking, construstion adhesive cant be used,it dosent allow the deck to breath underneith,it wont help the finish on the top last any longer,it wont help cupping or warping,it is problematic like Steve and I both think.

Kai, you take a sucker punch at me and my trade and my friends you are going to get it right back at ya. John

My apologies John and Steve. I have a great deal of respect for good carpenters. However, I do see a lot of new construction of supposed quality rotting away, everyday.

You are right about using the the right materials to begin with. I wouldn't choose cambara, if I were building a deck for myself. It's not a bad material, it just needs more care.

Kai,
I stand by what I said. Prefinishing the top of the deck is a bad idea. It's a jobsite, so you're gonna end up with scratches, footprints, and other blemishes that always occur during construction. I always sand down the deck when I'm done, before "finishing"...because it's necessary for a beautiful job.

As far as the 3/16" gap...you read about that in some literature put out by CECCO trading? they are a reseller of wood. what do they know about real life deck construction? John and I build decks everyday. we know. If you want to ventilate a deck, building it with huge gaps won't help. you need cross ventilation.

I've been building decks for many years, and i've explained alot of my techniques here for all to read. You can learn from my experience, or go and make your own mistakes...don't matter to me.

have a happy new year. i'm heading for Costa Rica on tuesday to have a much needed 3 month vacation in my funky beach shack.

steve

Peace bro, kaie I am thinking you really dident know what you were geting into. On the flip side > John is wondering how it is you see all the rotting decks every day????If your a code kinda person, in construston some how,, have a lot of exposure to decks in some way. Reason Im asking is the trade could use a lot of input right now. Its on a roll and has been for a few years and I agree with you. There is a lot of bad work being installed, these out door areas can be built to last 50 years or more. Do you have some input that will help?? Im for it.

Yo Steve,,You have a swim in that green/blue water for me!! and a little taste of the Rum as well. Go Get Em Bro!! J

John mon,

Happy New Year (feliz ano nuevo)

As I've offered in previous years...you have a standing invite to come visit. There's always a hammock for you.

I have to put a new roof on my house this trip (corrugated metal). I will probably have to rip out the old rafters too (termite damage). I'm gonna cut down one of my trees to get the wood for the rafters, etc. (I'll post photos). So come on down for my roof building party. I can't get Tecate, but CR has some really good beer, and great rum.

I have internet in the jungle now, so I'll be checking out the forum from my hammock.

vaya con Dios dude

steve

Steve,
If I hadn't just done it myself I would have thought the same as you. But the prefinished cambara stood up to the construction traffic well. So I will have to respectfully disagree.
Given your experience with decking on flat roofs, you must know quite a bit about ventilating where there is potential standing water, which is the situation that I was faced with. Given that situation, you don't think that a generous spacing would improve ventilation? Of course using the proper materials would also seem to be very important. It looks to me like ipe would be the best decking material in terms of all around durability. Is that your opinion?
Enjoy your vacation.

John,
I work with an older carpenter who knows quite a bit about good building practice. One of his sayings is, " A carpenter's job is keeping the water out of the house." As you said there's a lot of building these days that doesn't follow that tenet. Usually it seams to be a combination of bad design and bad practice, not to mention inferior or inappropriate materials. It's a very important subject that seems to have a lot to do with economics.

The only opinion that I will humbly offer is that routine maintenance is very important. If you don't have room in your budget to maintain your deck (or house), then you really can't afford to build it in the first place.

A healthy and prosperous New Year to both of you.

Kai

Kai,

I don't mind if you disagree. I build decks my way...not necessarily the way everyone else builds them.
You can read conflicting advice here by seasoned professionals. Is there a right or wrong way? That's up
to the reader to decide. My procedures are based on years of experience, but sometimes I change...I can learn
things here too.

There are a few reasons that I don't pre-finish my decking. I use Penofin as my finish. It's a penetrating
oil, but nothing can penetrate too deeply into Ipe. I really don't like handling boards covered in oil, as it'll get
on my hands...and it's nasty stuff. Then I countersink and plug my decks, so I have to sand down those plugs later
on, and the penofin would foul up my sandpaper, and you can't just spot sand anyway. Also, a deck is a job site,
and as such, it will get scratched, dirty, etc. The only benefit of pre-finishing is that you can coat the
bottom and the edges...which are difficult or impossible to finish afterwards.

None of the roofs I work on are flat. They all are pitched for drainage. One side could be 4" off the roof,
while the other could be 16". Ventilation isn't too much of an issue, as there is no standing water. Roof sites
are almost always sunny, and windy. My standard gap is 1/16" which will expand to 1/8" after shrinkage. I have
different sets of spacers (which I make). If I'm building in a shady backyard, I'll use 1/8" spacers...because
when the trees drop leaves, flowers and seeds, small gaps might get clogged, and the resulting standing water
can cause decking to expand, which can close the gaps even more.

Ipe is the best decking material, in my opinion. Down here in Costa Rica, we have other great hardwoods, but they just don't get exported to the U.S of A. Until I find a better decking material, I'll probably stick with Ipe, unless it's not in my client's budget. I'd like to try Siberian Larch, and I may try Garapa gold...only problem is, is that they aren't available in the Brooklyn area

This is not exactly a vacation, as I've been coming down here for 30 years...at least 3 months per...and with
a funky old house like mine, there are always projects. 2 acres of land also requires a lot of maintenance, or it'll be back to jungle in no time at all.

At least I have the time to write long replies like this one.

steve

Kai,

I don't mind if you disagree. I build decks my way...not necessarily the way everyone else builds them.
You can read conflicting advice here by seasoned professionals. Is there a right or wrong way? That's up
to the reader to decide. My procedures are based on years of experience, but sometimes I change...I can learn
things here too.

There are a few reasons that I don't pre-finish my decking. I use Penofin as my finish. It's a penetrating
oil, but nothing can penetrate too deeply into Ipe. I really don't like handling boards covered in oil, as it'll get
on my hands...and it's nasty stuff. Then I countersink and plug my decks, so I have to sand down those plugs later
on, and the penofin would foul up my sandpaper, and you can't just spot sand anyway. Also, a deck is a job site,
and as such, it will get scratched, dirty, etc. The only benefit of pre-finishing is that you can coat the
bottom and the edges...which are difficult or impossible to finish afterwards.

None of the roofs I work on are flat. They all are pitched for drainage. One side could be 4" off the roof,
while the other could be 16". Ventilation isn't too much of an issue, as there is no standing water. Roof sites
are almost always sunny, and windy. My standard gap is 1/16" which will expand to 1/8" after shrinkage. I have
different sets of spacers (which I make). If I'm building in a shady backyard, I'll use 1/8" spacers...because
when the trees drop leaves, flowers and seeds, small gaps might get clogged, and the resulting standing water
can cause decking to expand, which can close the gaps even more.

Ipe is the best decking material, in my opinion. Down here in Costa Rica, we have other great hardwoods, but they just don't get exported to the U.S of A. Until I find a better decking material, I'll probably stick with Ipe, unless it's not in my client's budget. I'd like to try Siberian Larch, and I may try Garapa gold...only problem is, is that they aren't available in the Brooklyn area

This is not exactly a vacation, as I've been coming down here for 30 years...at least 3 months per...and with
a funky old house like mine, there are always projects. 2 acres of land also requires a lot of maintenance, or it'll be back to jungle in no time at all.

At least I have the time to write long replies like this one.

steve

I'm one deck builder that thinks a 3/16" gap is ok on decking, but not for ventilation. The reason is I do a lot of re-construction of decks & see a lot of problems from deck guys putting the boards too close together. I've seen gaps so tight that when it rains the boards swell & don't allow for drainage. The biggest thing tho is the smaller gaps trap & hold dirt & leaves which promote decay. Appearencewise the tight gaps are nice, but not for the longevity of the decking.

For hardwoods like ipe that are very rot resistant & shrink less I like to use 1/8" gaps.

Al