# Deck Board Gap?



## cibula11 (Jan 6, 2007)

I will soon be constructiing a new deck and will be using PT 5/4 x 6 boards for my deck planking. I have heard conflicting views on whether to gap the boards when laying the decking. Some say you need to gap 1/8" or so and others say to butt the boards tightly to one another. Which is correct?


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## AtlanticWBConst. (May 12, 2006)

cibula11 said:


> I will soon be constructiing a new deck and will be using PT 5/4 x 6 boards for my deck planking. I have heard conflicting views on whether to gap the boards when laying the decking. Some say you need to gap 1/8" or so and others say to butt the boards tightly to one another. Which is correct?


PT deck boards: NO GAP. 

Place the deck boards side by side. 
(Check for alignment every 6 boards out, or so - If it's a long length deck board arrangment. You could also pre-snap reference lines over the joists prior to the start of the decking work).

Pressure treated deck boards, as is the case with all PT lumber, shrinks considerably after it is installed and slowly dries out. 

Deck boards placed side by side will give you 1/8" to 3/8" gaps between the boards when it is fully seasoned (3-6 months)


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## boman47k (Aug 25, 2006)

Just read an article about some pt being predried now. In that case, shouldn't a gap be left beyween the boards? Like maybe a nail used as a spacer?


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## AtlanticWBConst. (May 12, 2006)

boman47k said:


> Just read an article about some pt being predried now. In that case, shouldn't a gap be left beyween the boards? Like maybe a nail used as a spacer?


Pre-dried, yes.


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## cibula11 (Jan 6, 2007)

Most PT is not pre dried, correct? So I should NOT leave a gap? That's what I thought, but some were saying that it would be a drainage problem if no gap was left.


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## KUIPORNG (Jan 11, 2006)

I am more worry that small animals find a comfort home and decide to stay there if there is no gap... but then a no gap deck must be very comfy...


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## AtlanticWBConst. (May 12, 2006)

cibula11 said:


> Most PT is not pre dried, correct? So I should NOT leave a gap? That's what I thought, but some were saying that it would be a drainage problem if no gap was left.


Regular PT, that is not sold specifically as "Pre-dried" = place side by side.

Specific "Pre-dried" PT, talk to the supplier to ascertain exactly what that labeling means in terms of the decking they are calling "pre-dried"...Their definition of this....


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## RYANINMICHIGAN (Jan 20, 2006)

I get PT decking as tight together as I can.


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## cibula11 (Jan 6, 2007)

Thanks everyone!


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## crecore (Nov 2, 2005)

I doubt you will find predried, depending where you are. You can tell the difference by weight too!


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## cibula11 (Jan 6, 2007)

If I don't gap the boards, when they expand, will the boards cup and warp since there is no gap?


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## KUIPORNG (Jan 11, 2006)

I remember reading from the web that nowaday, they don't gap, and they don't expand no more... gap is for old days installation...etc... forget where reading those though...


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## AtlanticWBConst. (May 12, 2006)

cibula11 said:


> If I don't gap the boards, when they expand, will the boards cup and warp since there is no gap?


Cib,

They Don't expand, they *shrink* as they dry.


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## Mike Swearingen (Mar 15, 2005)

IF you have p-t wood that is stamped KDAT (for Kiln-Dried After Treatment), then you can leave a nail size gap, otherwise butt the deck boards tightly together and they will leave a nice drainage gap when they dry out.
Most p-t wood is allowed to "drip dry" on a concrete pad (that drains the excess chemical back into a recycling pit) at the manufacturing plant, and the moisture content stays pretty high for a long time. Most manufacturers recommend - for best results - allowing up to 6 months for the p-t wood to dry out in place before staining or painting. 
Mike


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## boman47k (Aug 25, 2006)

Brings up another question, but I wll make seperate post for it.


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## The professional (Jun 14, 2007)

*Spacing, or staining*

All pt lumber dries at a different pace. One sure way to find out if it is dry or not (for spacing or for staining purposes) is to try the water test. If you place a drop of water on the pt and it soaks in quickly then it is dry. It could of been sitting at the retailer for months who knows.


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## AtlanticWBConst. (May 12, 2006)

If you are really concerned about the moisture content of your PT lumber to be used....you could always, just get on Amazon and order yourself a ''moisture meter''. We have one that we use alot for moisture damage work.....


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## boman47k (Aug 25, 2006)

> All pt lumber dries at a different pace


Difference in moisture content seems to be evident when loading and unloading pt lumber. Significant difference in the weight of same sized lumber.


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## cibula11 (Jan 6, 2007)

So, what are the consequences should the deck boards be dry and I butt them together anyway? It is tough to tell on these boards. I got them from a big box store, so there is a good chance they sat around for awhile. I'm just not sure if they sat there long enough to dry out. 

I even thought to be on the safe side, I could use a trim nail as a spacer just in case.


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## cibula11 (Jan 6, 2007)

Anyone with any last opinions??


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## AtlanticWBConst. (May 12, 2006)

cibula11 said:


> Anyone with any last opinions??


Yes, Please stop obsessing and over-analyzing this. It's actually been answered already; Side by side, no gap.

Really now: It's a pressure treated deck for goodness sake, it's not a piece of museum art. The only thing that's going to get close to the deck = is people's feet - while they are walking on it.
Once it's all done, seriously, NO-ONE is going to notice whether the boards are 1/8" spaced or 3/8" spaced, while they're eating their hamburgers & hotdogs, listening to music and watching fireworks....


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## The professional (Jun 14, 2007)

Good Answer Atlantic


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## cibula11 (Jan 6, 2007)

sorry. 
thanks for the reminder


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