What threaded rod for a pier

[Spookyer]

Hi all, getting close to concreting the threaded rod in for the piers.

With the rod should I buy galvanised or stainless?
Is 12mm diamter rod sufficient or should I go say 16mm?

I will have payloads of up to 30kgs on the piers plus counterweight plus weight of mount etc.

[leon]

Hi Brett, 12mm Gal would be sufficient, no need for stainless steel, that stuff is pretty expensive.
I do presume you mean you are placing these rods into the top of the pier when the cement is still soft.

Leon

[glend]

Bunnings sells formwork lag bolts that work just fine. They are 12mm galvanised and have an L bend in the end you put in the concrete. Couple of different lengths I used the longest ones.

[Spookyer]

Yes Leon, I will set the rod into the concrete during the pour so later I can bolt my steel pier down to it via holes I will have in the base plate of the pier.

Glen I will check out the lag bolts, can't find them on their website but will ask in store.

Brett

[pmrid]

Brett, I've done 3 piers and all different. In one, I decided to have adjustment for true level on top of the pier and on another, I went for adjustments at the base and - wait for it - you guessed it, in the third, I went for both. In the one I had the adjusters at the base, I wanted to be sure the bolts wouldn't rust out in the concrete so I went SS. In the others, I went for plain gal. In each case, 12mm was more than enough. 3 or 4 of those and the pier is not going anywhere.

Peter

[jenchris]

Pop some masking tape over the exposed thread. Concrete is hard to remove from gal.

[leon]

Yes that is a good point Jennifer,

leon

[muletopia]

Hello Brett
Yep, tape those bolts. I did not like the idea of adjustment plates,rat cages or shims to achieve level. In obs section, beginners pier complete thread, I describe how I cast 16 mm galvanised threaded rod in the concrete. The absolutely rigid top plate is easily level enough for my HEQ5 pro mount.
Certainly keeps me happy.
Cheers
Chris