Securing joist hanger to steel

[marsaday]

My speedy joist hangers are just bent over and sitting on top of my steel at the moment.

I thought about having them welded to the tops, but wondered if there was a screw i could use to secure them to the steel. I could easily drill a 2-3mm hole through and then put a screw in.

I know you can shot fire into steel, but i will prefer welding as he has to come out and do some welding for me anyway.

 

[r896neo]

Just in case you don't get screws etc sorted as far as i know you can't weld galvanised steel to normal steel unless you grind/ remove the coating off every one of them.

 

[marsaday]

Well i bought these from screwfix today
http://www.screwfix.com/prods/62491...s/Self-Drilling-Screws-4-8-x-16mm-Pack-of-100

i drilled a 3mm hole, but i couldnt get it to screw in.

Thought i would come back and ask anyone here for more ideas/products.

I will really try and screw the hangers down so still persuing this line of thought at mo.

 

[JamesBeasley]

How thick is the steel you are drilling into?

I would recommend screwing rather than shot firing or welding as.... you could split the jiffy hanger (speedy hanger) and render it useless and as r896neo says welding galv to mild steel is a tricky business and a very specialist one at that.

I have drilled tek screws through 20mm steel before with pre-drilling see link - http://www.evolutionfasteners.co.uk...201004301139527356EvolutionHeavyTeksGuide.pdf

If you phone them they are very helpful and can deliver next day. I had been dubious about a tek screw for 20mm steel but theirs do work.

 

[noseall]

You would normally ask for pre-drilled holes in the web say m12's staggered at 600mm c/c. You would then bolt a timber joist into the flange allowing you to fix the jiffys into the timber with screws/nails.

 

[marsaday]

the steel and floor is in place. i have a joist bolted into the flange of the steel. so all joists have been nailed to this joist. however the tops of the hangers are just bend over on to the top of the steel. i now want to secure the hangers into the of the steel.

i have beentold i dont need to bother with this, but if i can do it easily i would prefer to.

the steel thickness is about 8mm i think. i drilled a 3mm hole for the screwfix screws, but i couldnt get them to bite

 

[Deluks]

So if if the hangers are screwed/nailed into both the joist, and the 'flange joist' then you don't need to do any more, these will be redundant.
The screws you have are for fixing light gauge steel, not structural sections, no wonder they won't go in.
Try re-drilling out the holes in .5mm increments until they go it without too much fuss. I'd try the 3.5 but up it to a 4mm if it's hard work putting the screw in.

 

[marsaday]

ok, thanks i will try the 3.5/4mm method and see what happens, but you are saying this is not necessary any way ?

Yes the joists are face nailed to the steel/joist in it, but they are designed to wrap over the top (so i thought). this is why i am wanting to screw into the steel. These are not masonary hangers, but the timber to timber ones and so a bit weaker in construction.