I'm putting down deck boards, and I'm worried about shrinkage. How should I space them to account for that? Or should I dry them first? About 1/2 the deck is dried. Most of it had to be re-spaced and quite a few boards replaced because of how much some of it shrank. I'm using 2x6s for deck boards. Trying to figure out how I can avoid more issues.

I'd talk to someone at McCoy's or a building supply store (BMC) etc NOT Lowe's or HD.

I don't know what normal board shrinkage is but quality is gonna be better from one of those places versus the box stores

I believe they should be dried first. There's moisture meters that can be used to determine when it's good to install.

If you can find a place that sells kiln-dried lumber, go there.

Ya, I've been getting it from McCoy's cause they load it for you. Makes life easier. But I'll see what they know.

I think installing dried boards would be the best way. I built a deck a few months ago and the variance of shrinkage from one board to another was crazy.

I used the Camo screw system and it had a 1/16" gap jig. Most gaps now are about a 3/8" but some are more like a 1/2".

It was also frustrating how much difference there was in actual width of some of the boards from the start. Some were off by almost a 1/4". That's ridiculous. Material was from Lowe's so hopefully McCoys is better quality.

I highly recommend a BoWrench board straightener.

Ya, I think I'll have to figure out a way to dry them. Maybe sticker them and strap them down on the trailer, keep a fan on them for a week or two.

Sounds like you had a very similar experience. I have the Camo straightener which works okay, but I'm gonna pickup the one you recommended. Seems like a better option, more leverage.

Replacing 80s 2x6 deck boards has been quite a revelation in quality (not).
I agree with all above, so only can share that
between Lowes & HD, the latter wins hands down.
During COVID, HD cherry picked - better than I - then loaded curbside a primo day's work of replacment deck boards. I just had another Lowes board pop up out of .... deck Screws!

B/c we are so 70s about protecting the planet, NOW legislated as never before, in order to find a treated equal to the old, exisiting, only ground-contact deck boards are purchased.

I differ from spacing concerns in that I prefer them .... Wider.
The 4 kids are now grown but bring smaller versions at times that also need their refuse disappear between the deck cracks. In-the-day, the SOP spacing was a galv. ringshank nail ... which turned into 1/2-5/8" or better in the 6-12 months it took for central Texas sun, wind, storms to dry them out.

Beertime fun is tossing beer caps, goal is that they disappear on one throw ... becoming someday akin to the bottecap alley next to The Dixie Chicken.

Hope you're doing this at dawn or better - November if in Texas.

That was a great read. I don't mind the wider gaps as long as they're consistent. Im shooting for 1/8".

Unfortunately I've drug this one out, and the client isn't thrilled, so I'm dealing with it in this heat. I call it in about noon, because the heat is unbearable.

When building decks I do not leave any gaps. PT wood at minimum will shrink at least 1/8 inch per board so 2 together gets you roughly a 1/4 inch gap.

Home depot PT wood seems to shrink less than lowes and mcCoy's pt.

You put it down wet? Another problem I had was half the deck is against the house foundation. Some boards came off like 1/2-3/4". Looked really bad.

OnlyForNow said:

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I'd talk to someone at McCoy's or a building supply store (BMC) etc NOT Lowe's or HD.

I don't know what normal board shrinkage is but quality is gonna be better from one of those places versus the box stores

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Haha. As someone who buys huge lumber packages from mccoys, i can guarantee you their quality of lumber isn't much different from the big box stores.

My framer routinely rejects 50-60% of a drop from mccoys.

If you're in/around Austin or B/CS, I've got a Bowrench I used when I did my ipe deck a while back. Will make a deal on it.

And +1 on no gap. If you need a gap to help align, use a 6d nail or similar (around 1/8" dia).

JP76 said:

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When building decks I do not leave any gaps. PT wood at minimum will shrink at least 1/8 inch per board so 2 together gets you roughly a 1/4 inch gap.

Home depot PT wood seems to shrink less than lowes and mcCoy's pt.

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This. Most wood you get from anywhere has a little moisture. Certainly more than it's going to have and get sitting in 100 degrees at 10% humidity for 18 days. I butt my new wood up tight.

And the lumber from McCoy's isn't better than a box store. It's all the same. The support, loading, and caliber of employee is what's different and that's why I go to McCoy's.

I built a deck for a client a few months ago. The boards were soaking wet coming out of the bundle. I sucked them as tight as possible to one another anticipating shrinkage. I haven't been back to see how much the boards shrank but haven't gotten a call either.

I just stacked and stickered and threw ratchet straps on. I may put a fan on them and throw a few more heavier duty straps. I'll be gone a week, so we will see how things go. Basically a $1000 bet that they'll dry okay.

You're probably right. The more reading I've done, the more I'm thinking it'll be fine Just putting it down as is, leaving no gap. This stuff wasn't nearly as wet as the last load, so that's promising as well.

One thing to keep in mind is that everyone in this market is getting all of their treated lumber from a handful of options. Yellawood comes from Columbus. Prowood comes from New Waverly. There are a few small treaters in the greater Houston area. 95% of what you will ever buy locally (B/CS) is going to come from one of these places. Now there could possibly be differences in lumber quality from treater to treater because of the particular mills they buy from, but then again in most cases they buy from the same mills.

As far as how wet the lumber is, most of these treaters are turning over their entire inventory every 5-10 days. The lumber is dried on a "drip pad" but that's the extent of it. The retail stores are receiving this product within a few days of treatment MAX. The moral of the story is that ultimately there won't be a ton of difference from place to place, and as long as you are dealing with treated lumber you will have the same shrinking issues (KDAT excluded obviously).