# Fasten deck board from under deck



## resonator (Sep 14, 2010)

I want to fasten my 2"x6" PT deck boards to 2" PT joists from under the deck for aesthetics, but WITHOUT hidden fasteners. ie. using screws on an angle from the joist up into the 2" deck board from underneath.

Its a pool deck (salt water to boot) so lots of water, salt, etc, and i dont want to pay for stainless steel hidden fastener tracks and i don't like the other fasteners. It looks like i can get a good 1" of screw in both the joist and deck board if on the proper angle.

Has any one screwed up from under the deck like this (without fastener tracks, etc) ? 

Or, what about using 1" zinc L brackets at the joist and deck board (under the deck, 1 screw into the joist, the other screw into the deck). 2 brackets at each joist, same spacing as if was being screwed from the top, but screwed from under the deck, thats all. 

Or what other DIY contraptions work for undermounting the deck boards? Much appreciated...


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## Scuba_Dave (Jan 16, 2009)

I used the small simpson L brackets at my last house
Not sure what exactly I used for screws into the deck board -PT
It was a small deck bordering my hot tub
Less then 40" wide & about 8' along the tub
When I told the Inspector the size & inquired about a permit he said it didn't qualify as a deck :laughing:

Not sure what is required by code for attachment

I did the hidden fasteners on my deck here
Both methods were a PIA,...lots of labor


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## unlvrebel (Jul 20, 2010)

Kreg makes a jig just for this. You could probably get by without the jig, but I think the $100 would be well spent...

http://www.lowes.com/pd_177429-39450-KJDECKSYS_0__?productId=3186191&Ntt=kreg&pl=1&currentURL=%2Fpl__0__s%3FNtt%3Dkreg#prod-tabs


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## Michael Thomas (Jan 27, 2008)

These are also several systems that secure the deck boards to the joists using plastic or metal cleats set into slots cut with a biscuit jointer.


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## COLDIRON (Mar 15, 2009)

Might look good when done but consider the strained neck and arms and time. I would definitely find something from above that's hidden.


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## kwikfishron (Mar 11, 2010)

PT decking warps, cups, twist, and checks. Your “toe screw” idea would be a big fail. Your PT decking needs to be solidly secured.

If you live in a salt environment all of your hardware and fasteners need to be Stainless Steel. 

Your zinc L brackets will be zinc rust dust in 2 years.


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## cocobolo (Dec 16, 2008)

kwikfishron said:


> PT decking warps, cups, twist, and checks. Your “toe screw” idea would be a big fail. Your PT decking needs to be solidly secured.
> 
> If you live in a salt environment all of your hardware and fasteners need to be Stainless Steel.
> 
> Your zinc L brackets will be zinc rust dust in 2 years.


Whether or not the PT lumber will do all of the above is dependent on how it is treated after it leaves the vat.

Unfortunately, in most cases, the lumber is pulled from the vat - let drain for a day at the most - and then is put on a truck for delivery to a lumber yard, where it is left out in the sun.

Under those circumstances, the wood is almost guaranteed to destroy itself.

Once lumber is pulled from the vat it is supposed to be left to drain for 4 days. Rarely is this done unfortunately.

If you can find a lumber yard which keeps the wood wet on sunny days by the use of a sprinkler, you may have better luck. Then you need to take it home, store it under cover and air dry it properly in order for it to stand a chance of staying flat. Nailing it, or indeed fastening it in any way to the deck absolutely will not guarantee that the wood will not do everything that ron says. 

You really do need to dry it flat yourself.

A nicer option is western red cedar.

As for the S/S fasteners, that's nice if you have the funds. But here on the west coast, in a totally salt environment, we have used hot dipped galvanized nails for decades with success.

In fact, I use only galvanized nails outside _or_ inside. As even indoors in this environment, ordinary steel nails will eventually rust.

S/S screws do cost far more than any nails, but if you only need two or three hundred, you might get a decent price at your marine store. I think we pay around 20 cents each for 2" S/S screws here as long as we buy them by the 100.

Have you considered using the screws from the top, countersinking about 3/8" and plugging? It's not that difficult and works well. Plus doing the work from above is far easier on the body. The plugs will all but disappear after sanding and perhaps staining.


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## mrgins (Jan 19, 2009)

surely with the new treatment of treated lumber, you need SS fasteners anyway.


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## cocobolo (Dec 16, 2008)

mrgins said:


> surely with the new treatment of treated lumber, you need SS fasteners anyway.


That's quite possible. 

Are you speaking of Cu HDO, or ACQ? The earlier CCA was OK with galvanized nails.


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## mrgins (Jan 19, 2009)

CCA was outlawed some time ago. The newer stuff will eat anything that is not SS


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## Gary in WA (Mar 11, 2009)

“Fasteners and connectors exposed to, and located within 300’ of a saltwater shoreline shall be stainless steel grade 304 or 316.” IRC 2006 Deck Code, page 2: http://www.lancova.com/deckinfo.pdf

I wouldn’t drill holes every 1-1/2” apart in the top (tension) edge of the wood joist to weaken it. 

Gary


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## cocobolo (Dec 16, 2008)

mrgins said:


> CCA was outlawed some time ago. The newer stuff will eat anything that is not SS


I understand that the manufacturers of CCA products actually bowed to public pressure and voluntarily ceased to use this in about 2003.

Hot dipped galvanized nails are still OK with the newer stuff. Stainless steel is likely a bit better.


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## cocobolo (Dec 16, 2008)

GBR in WA said:


> “Fasteners and connectors exposed to, and located within 300’ of a saltwater shoreline shall be stainless steel grade 304 or 316.” IRC 2006 Deck Code, page 2: http://www.lancova.com/deckinfo.pdf
> 
> I wouldn’t drill holes every 1-1/2” apart in the top (tension) edge of the wood joist to weaken it.
> 
> Gary


Thanks for that info Gary.

I had not heard of the 300' rule before. We have always used H.D. galvanized nails up here, regardless of the type of wood we use. Currently, our place is 13 years old and no problem with any of the nails.

Since I am much closer than 300' to the ocean, I guess I will really have to bend my tape measure all over the place to get it to read 300'. 

I wonder what happens between 299' and 301'?


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## kwikfishron (Mar 11, 2010)

300’ doesn’t hardly seem far enough. 3 mi. inland and we still have significant corrosion issues that you don’t see at the 7 mi. mark. Although the difference in corrosion rate is noticeable from a front row house and one that’s just a block inland.

There is no doubt that hot dipped galvanized (not electrostatic) will work in a salt environment. My lumber rack is galvanized with no issues. Most of my deck hardware, beam hangers, post base and the like I have made locally and sent to the galvanizer. I’ve never seen any of that fail yet.

The problem I have with galvanized nails at the coast is that 1 in few hundred will fail. That doesn’t sound like much but when after a year or two from the time I installed that beautiful cedar lap on your house you’re calling me back to point out the four or five rust streaks running down the walls.  That’s just not acceptable.
The same thing with decks and fences , I frame with galvanized if the nails are hidden but any nail that can be seen is SS.

SS is expensive without a doubt, $10-12 a pound vs. $2 but for me the extra $300 on that $18,000 siding job is well worth the piece of mind.


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## cocobolo (Dec 16, 2008)

I think I pretty much agree with every word you say Ron.

You may know that I live on a small island which is completely swept by salt winds 12 months a year.

I can't say that I have any rust streaks from galvanized nails on my place - yet - but that doesn't mean it won't happen. Our island - with 199 lots on it - is only 1 1/2 miles long and .4 mile wide, but it is substantially covered with evergreen trees.

Maybe all this evergreen protection makes a difference, I really don't know.

The next time I go to one of the "inside" properties, which in many cases would be barely over 300' from the ocean, I will have a good look to see how the nails are surviving.

One thing I might mention from experience is that when driving H.D. galvanized nails, occasionally the galvanizing will physically break off the head of the nail. In that case it is necessary to pull the nail and replace it.

If you have driven more than a few boxes of these, I'm fairly sure you will have had the same experience.


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