Deck screws how many per board per joist

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Forum topic by MHW posted 05-09-2017 04:33 PM 12786 views 0 times favorited 10 replies Add to Favorites Watch
View MHW's profile


8 posts in 1050 days

05-09-2017 04:33 PM

Topic tags/keywords: deck screws

Do I really need 2 screws per joist on my deck boards rather than doing 2 screws for one joist and then one on the next joist? 10 ft p/t boards on 16” joists.

10 replies so far

View crank49's profile


4032 posts in 3614 days

#1 posted 05-09-2017 04:52 PM

Two screws to prevent cupping of deck boards.

View dday's profile


173 posts in 2072 days

#2 posted 05-09-2017 05:07 PM

Two screws to prevent cupping of deck boards.

- crank49


View JCamp's profile


1050 posts in 1193 days

#3 posted 05-09-2017 05:13 PM

2 is fine as long as its a 6inch wide board. I have, and have known ppl, that swear by using 3 screws in a 6in wide board. Slightly over kill but they will not move

-- Whatsoever thy hand findeth to do, do it with all thy might

View johnstoneb's profile


3131 posts in 2815 days

#4 posted 05-09-2017 05:55 PM

You don’t say how wide. 4” 1 screw alternating side would work. 6” you need 2 per joist.

-- Bruce, Boise, ID

View LiveEdge's profile


600 posts in 2263 days

#5 posted 05-09-2017 06:05 PM

If you are going to go through the work of doing your own deck, pay the extra $10 in screws and do the extra time to put the additional screws in. It’s not the place to try to cut corners.

View DrDirt's profile


4600 posts in 4385 days

#6 posted 05-09-2017 07:06 PM

Depends – There are also hidden fastners which is what I did with my decking… where there is a biscuit made out of plastic with a built in spacer, so that you would hold the board by its edges

Then I use two screws per board on the joist at each end.

For direct screw down… the screws hold the board in place, and prevent cupping, thus 2 is standard.

-- “The two most important days in your life are the day you are born and the day you find out why.” Mark Twain

View OldCoach's profile


51 posts in 1517 days

#7 posted 05-10-2017 02:11 AM

Not to change the subject, but I built a deck 16 years ago using deck screws, the green ones. Never have I been so disappointed in a product. I cannot tell you how many screws failed due to rust and decay. I used two per joist on 6” wide boards by the way.

Last fall I removed this deck and replaced it with concrete. I would estimate that 90% of these deck screws were decayed to the point where they were no longer doing the job they were designed for. Plus the fact that now I have all this deck wood that I have to spend so much time just trying to get pieces of screws out in order to reuse for planter boxes or any other projects I want to use it for. I used 35 pounds of screws to build this deck. After demo, I have less than 5 lbs of screws that are not decayed that I can reuse on these other projects.

If I had to do it all over, I would use nails. Just my experience.

-- Play cowboy on weekends and make sawdust in between when not watching football

View Matt Hegedus's profile

Matt Hegedus

147 posts in 1436 days

#8 posted 05-10-2017 04:19 AM

Built about 20 decks start to finish with a crew, and we always used 2 screws on wood decks, (torx head outdoor screws, predrilled with an 1/8” pilot hole) UNLESS we were using composite decking boards with hidden fasteners. Hidden fasteners required 1 screw per joist, but these boards were not prone to cupping.

-- From Pittsburgh, PA

View Robert's profile


3643 posts in 2123 days

#9 posted 05-10-2017 01:45 PM

Countersink/predrilling make for a professional job. This is especially critical on butt ends.

And don’t over screw the screws even counter sinking this can result in splitting.

I think sanding and using a stain/sealer really makes it a good job, even with PT wood.

I’ve built quite a few decks and I really think 12D stainless steel ring shank nails are worth considering.

-- Everything is a prototype thats why its one of a kind!!

View ArtMann's profile


1467 posts in 1459 days

#10 posted 05-10-2017 04:33 PM

All I want to say is that I have built several decks and I agree 100% with rwe2156. Ring shank nails are great but I would shoot them with a pneumatic nail gun. I am too lazy to hammer them in.

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