Replies

1. 
   JDRHI | Sep 20, 2002 04:17pm | #1

   Heres a question certain to get a plethora of contradictions.

   I personally install decking with the growth rings turned down. I`ve built MANY decks and have yet to have a problem. Be sure to screw off decking tightly and completely. I use three screws per joist. I also believe that the spacing of the decking may have more to do with cupping than the direction of rings. If wet decking is not permitted to ventilate and dry out, its going to cup.

   J. D. Reynolds

   Home Improvements

   "DO IT RIGHT, DO IT ONCE"

1. 
   booch | Sep 20, 2002 04:40pm | #2

   I concur on the "cup down". As for the moisture, yes that makes sense for no ventilation, but even on the highrise decks (off the second floor) the cup can occur. My FIL had one in South Carolina that I thought I could belt sand out as it was a small deck. Nightmare on a stick. Besides the toxic dust, which I didn't believe in at the time, I was left with shards from separated growth rings. Despite the sanding the shards kept coming back. They weren't very friendly with bare feet. I unnailed, then flipped them was the only cure. There was a place for Trex or equal.

   BTW what does everyone think about the plastic wood decking?

1. 
   scotcrpntr | Sep 22, 2002 10:25am | #24

   I used that stuff(Trex I believe) on docks on fresh water lakes. The guy I worked for loved it, but that may have had something to do with the mark up for all I know. I was only there for a year so I can't say anything about longevity tough I think I may go check it out for curiosity's sake now that  5 or 6 years have gone by. I can say that the stuff was a dream  to work with;routers like butter, weathers to the same consistent color and shade even when pieces are added at different times, no splitting or cupping, long lengths, and beautiful seams. All of these jobs were high end and most of these people really loved the consistency and conformity of the product. I thought it looked surprisingly cool and its recycled materials on top of it all. That said, for my own house(I live on a mud puddle) I prefer wood because i like the irregularities you find on even the finest work;diferent shades and colors, texture and grain,aging, yada,yada,yada,               scott

2. 
   Qtrmeg | Sep 20, 2002 10:19pm | #7

   Three screws per joist? Why?

1. 
   booch | Sep 20, 2002 11:25pm | #8

   He sells screws?

2. 
   JDRHI | Sep 21, 2002 06:31am | #10

   `Cause I just got the Makita cordless impact driver!!!!!!

   Like many here who believe boards can warp with cup up or down, three screws makes it that much less likely.J. D. Reynolds

   Home Improvements

   "DO IT RIGHT, DO IT ONCE"

1. 
   bill_1010 | Sep 21, 2002 07:45am | #11

   warp happens because of moisture. yes the growth rings will have some impact, but the reality is if the under side of your deck hosts a mold and mildew party weekly and the top side hosts one of those dehydrated tupperware parties. Cupping will occur because of that situation most likely. Not the growth ring factor as much.

   There is my two cents worth. I tend to follow best face theory. 

1. 
   JeffBuck | Sep 21, 2002 08:20am | #12

   best side up. Jeff.......Sometimes on the toll road of life.....a handful of change is good.......

2. 
   luvmuskoka | Sep 21, 2002 04:59pm | #14

   Jeff,

   Just throw down some sheets of 3/4" p.t. and say hell to cupping boards.Ditch

3. 
   BossHog | Sep 22, 2002 02:34am | #20

   "Just throw down some sheets of 3/4" p.t. and say hell to cupping boards."

   Great idea! Then he could add some green outdoor carpeting for the ultimate in luxury.............

   Then there was the old politician who went to see his doctor. He complained he was having to dodge issues he used to sidestep easily.

4. 
   booch | Sep 22, 2002 02:53am | #21

   Don't forget to drill a 4" hole for the cup. (good place to throw empties too.)

5. 
   luvmuskoka | Sep 22, 2002 05:31am | #23

   ...and find an old couch.....and pit bull.....Ditch

6. 
   JeffBuck | Sep 22, 2002 05:04am | #22

   I prefer T-111 'cause the grooves give it that "real deck board" look.

   Jeff.......Sometimes on the toll road of life.....a handful of change is good.......

7. 
   ANDYSZ2 | Sep 21, 2002 06:27pm | #16

    I use 5/4  treated board all the time and what gets me is over a third have the cup

   reversed  from one end to the other. Someone explain this to me? I use nail guns on most if they want screws I charge extra. I like to use stainless steel trim screws that have a self boring tip and a chamfer cutter under the head of the  screw. I want to try some underneath mounts to see if that reduces splitting.

                                                   ANDYSZ2

8. 
   bill_1010 | Sep 21, 2002 06:44pm | #18

    

    I use 5/4  treated board all the time and what gets me is over a third have the cup

   That happens at the mill, Tapered trees & poor milling practice.  Imagine a line through the very center of the tree. Its Z axis.  the mill starts on one side the Z axis and crosses it somewhere where the cut end up on the opposite side of the cut.  That will get you cupping different directions on the same board.

2. 
   BossHog | Sep 20, 2002 04:46pm | #3

   My thought is to put the best looking side up and ignore the growth rings. The boards may cup no matter which way you put them.

   My palm reader says tarrot cards are a crock

1. 
   noone51 | Sep 20, 2002 07:23pm | #4

   I'm with you Boss, Its not so much if the crown is up or down its more of how well you maintain the deck. Three screws per joist on 24" centers will adequately secure the deck boards and keep them flat if they are properly protected and that protection is maintained. A good power wash and a coat of Penafin every 18 months will do more for keeping a deck looking good and cup free than anything else.

3. 
   Piffin | Sep 20, 2002 07:51pm | #5

   Of course, everybody elsse is wrong [grin]! Use clear vertical grain fir and select the best side.

   There are good arguaments for either way.

   Select your corners men and come out slugging.

   :-)

   Excellence is its own reward!
4. 
   RobP22 | Sep 20, 2002 09:04pm | #6

   I guess if you are really concerned about it and not sure what to do, why not alternate every other piece, i.e. rings up, rings down, rings up, and so on. This idea would be similar to glueing up a solid wood panel. My personal opinion is that if the pieces are secured well to the framing you won't have a problem, so put the best looking face up as others have said.

5. 
   vasalesman | Sep 21, 2002 05:47am | #9

   I'm in an area where treated SYP is used on nearly all decks.   A fairly common technique that has drastically reduced warping & cupping is to run two kerfs lengthwise down the back of decking boards.  The depth is about half the board and the cuts are spaced to divide the face into thirds.  Sometimes it's done in the field but variations of it have been commercially available for years.  The commercial versions usually have widths from about 3/16" up to about 1/2".  The success rate is very high.  As far as using screws for flooring, I don't like them.  The reason is SYP, without a strict maintenance program, soaks up rain pretty quickly and in our climate dries back out quickly also.  SYP  reacts to moisture contact with large changes in width, around 8% from saturation to oven dry if I'm not mistaken.  These width changes occur regardless of what fastener gets used.  Now if you've got a fastener that doesn't have enough "give" to it, something else will.  Nearly always, the screwed down board will develop more splitting than one that's nailed with either ring or spiral shanks.  Nails have just enough give against the force of the board shrinking down as it dries to noticeably reduce splitting.  Screws simply lock the board too tightly into place and it can't move.  Now does this mean over a deck's lifetime that pieces may need to be renailed because they've worked loose?  Yes.  But would you rather have to renail a fairly decent board here & there or replace one that split all to pieces?   Something I've seen over the years also is that decks built in the fall or winter always age better, with less splitting, checks, etc. showing up.  I believe part of the reason is dried after treatment material is rare here, so jobs often start with soaking wet wood.  In the fall & winter the wood can dry out much more slowly than summertime.  Summer decks can start out looking great but begin showing heat and moisture damage often before the job is even finished because it dried in just a matter of days.

   Al

6. 
   goldhiller | Sep 21, 2002 04:52pm | #13

   Most decks in our area are built using treated SYP also, although clear cedar is becoming more popular because the price difference is now negligible.

   Our supplier sells only clear premium grade that’s been kiln dried the second time after treating, so we must allow for the expansion that’s inevitable when the boards absorb moisture on the deck. We always place the best side of the board up, although on our stock from this supplier, there isn’t an iota’s worth of difference. Some cupping is inevitable in a plain sawn deck board no matter which side is presented to the weather. Minimize the tendency with your water repellent.

   But if we’re using exposed screw fastening on a deck, we do something that I haven’t heard mentioned here yet…………we drill slightly oversized shank holes for each and every screw in the deck boards. This allows for movement of the boards without any splitting as the screws can now tip off vertical. Following this practice, we don’t have any boards that split. We use two 2 ½” screws per 5 /4” x 5 ½” deck board. We usually have 8 – 10 deckboards spaced, aligned, and clamped in position at a crack. One guy goes out in front and drills the shank holes while the other follows behind with the screws.

   Knowledge is power, but only if applied in a timely fashion.
1. 
   vasalesman | Sep 21, 2002 05:17pm | #15

   Nice idea!

   Al

1. 
   xMikeSmith | Sep 21, 2002 06:35pm | #17

   best side up never hurts... however... wood shrinks on the sap or bark side so if you put it bark side down it will tend to hump.. if you put it bark side up it will tend to cup....

   good discussion in Fred Hodgson's book "Light & Heavy Timber Framing " ... 1909..

   & Bob Syvanen "Tips of the Trade "  1980..

   but if you really want to know .. I'd ask Stan Niemec over in Knots...

   but hey, whadda i no ?Mike Smith   Rhode Island : Design / Build / Repair / Restore

1. 
   sawone | Sep 21, 2002 07:57pm | #19

   thanks for the info.  Turns out I had the answer all along.  I have Bob Syvanen's "more tricks of the trade"  1982  and it's been a big help to me in the past.  It's a little late for half of the deck ramp which is down bark side down but I will put the rest of it on the other way.  It's a handicap ramp so I'm not to concerned.  thank you for your time,    Sam