Screw to edge spacing

[gdcookuk]

I sure this has been answered before but I can't find it anywhere.

I am using 90x19mm Merbau

90x45mm Treated pine joists

10g Stainless Steel Screws.

Questions are:

1) how far are screws to be from egde of decking

2) How far are screws to be from end of decking (when butting decking boards against each other) and therefore how far from the edge of pine joist.

3) what angle cut back is needed when butting the decking boards together

See image below

88375

[Steffen595]

for Z you work out how much gap you want and how wide your boards are.
Say 90mm boards, 3mm gap
93 mm. Then you want 93/2=46.5 mm spacings between screws so it looks neat. From the edge then its 46.5/2-3/2=21.75 to be precise. Normally 2 screws a board will do.
For joints, if you want expansion joins you find another 2mm. In order for your boards not do split you should go 15mm in. Maybe you can do 10mm on merbau? Now you are in trouble because 15+2+15 is 32 already on a 45mm joist. Lucky me, only built a small deck, no joints.
Angles 90°

[Godzilla73]

G'day,

I built a 10x5m deck and didn't angle the butt joins and have had no issues with peaking/movement. Timber doesn't move in that direction, my screws are 15mm in both ways with the butt join screws angled slightly into the joist.

[stevoh741]

a 1-2 degree angle on the butt joins over joist is fine. Just dont square cut them. Just cause godzilla got away with it (for now) doesnt mean you will

[Godzilla73]

Just dont square cut them. Just cause godzilla got away with it (for now) doesnt mean you will

Mate, i've built a few with friends first while getting the low down to do mine, and never seen or heard of this, asked around today and got squat... You reckon i'll get a skate ramp effect going out there?

I'll take my chances and enjoy another beer. :2tsup:

[Steffen595]

what is the angle for? Could see the point if it was vertical, so you get some sort of a nose so water drips off?

[ringtail]

1 degree back cut is industry standard to ensure a tight join

[Godzilla73]

Must be just the cabinet maker in me then, making sure all is square and tight which the butt joins are even with a 90 degree cut.

Stevoh implies if you don't back them off a tad you'll get??? Be interested to know for future reference, but can't see an issue.

One of the decks i helped out on with my builder mates was 20 metres long, i've seen it 4-5 times in the 3 years since it was built and it still looks mint with 1/2 undercover and the other exposed.

Obviously can see the benefits of what Ringtail says and if that's what it's about then great, if i wasn't doing it myself then i'd appreciate a tradie puting in the time to do it, but i spent hours getting it right, from the stumps out of the ground to the final screw in the decking boards so not concerned just curious as to what "for now" means...

[stevoh741]

Must be just the cabinet maker in me then, making sure all is square and tight which the butt joins are even with a 90 degree cut.

Stevoh implies if you don't back them off a tad you'll get??? Be interested to know for future reference, but can't see an issue.

One of the decks i helped out on with my builder mates was 20 metres long, i've seen it 4-5 times in the 3 years since it was built and it still looks mint with 1/2 undercover and the other exposed.

Obviously can see the benefits of what Ringtail says and if that's what it's about then great, if i wasn't doing it myself then i'd appreciate a tradie puting in the time to do it, but i spent hours getting it right, from the stumps out of the ground to the final screw in the decking boards so not concerned just curious as to what "for now" means...

No need to get all upset about it godzilla. You are getting free trade advice so maybe try using a different tack than ignorance - sounds rediculous that just because you havent heard of it then it musnt be true??? Ok, so for further explaination on my previous post then here it is. 1. It ensures a tight join, 2. Is industry standard as Ringtail pointed out, and 3. slightly lessons the likelyhood of water being trapped in there - although I assume you did seal your ends?

You are right, timber will have minimal movement along the grain as most of it will be across the grain. However, to include the undercut (for reasons mentioned above) will only be the difference in time of you getting the cap off your beer. You say you have been a cabinet maker for 20+ years then surely you of all people could work out it is as simple as holding the decking board up a few mm's when cutting or even easier, just placing a packer under the board alongside the cut to give the slight angle. Square and tight is great for indoor but allowances need to be made when working outdoors. Also this is a simple way for a DIY'er to get professional results.

I am happy to give detailed explanations when asked, however dont make an ass of yourself just because you might not understand how it is done. If I were building a kitchen and you provided advice on an aspect I'd enquired about then I would explore an explanation ect with you not just post back that I'd never heard of it and everyone else is an idiot. Like I said earlier, yours may have turned out great but not everyone here has had 20+ years experience on the tools like you. :2tsup:

[Bedford]

:spyme:

[Godzilla73]

Who me? Nah never...:U

[shauck]

It's the same as when you make a box for cabinets to sit on, or a bulkhead and the mitre joins are cut at 46 degrees instead of 45. It ensures a tight join.

[Godzilla73]

Ahhh one day I'll learn how to type what I actually want to get across. 'till then you'll have to put up with my stupid questions...

[intertd6]

When using good quality & sharp power tools there is no need to ever undercut end cuts of decking & its not industry standard practice or even ever an archictects spec, some fanatic tradesman may insist on doing it to get a fantastic tight joint.

regards inter