Torx concrete screws: are they the same as framing screws?

[ToughButterCup]

I suspect not, because simple framing screws (i.e screws not intended for use in concrete) don't have groove in the thread do they?

Like this

 

These are the ones for concrete aren't they?

(apologies for the blatant copyright rip off)

 

Yet there are plenty of adverts for screws to go into concrete that don't have the grooved thread.

These for example are advertised as

'... High quality Concrete Anchor External Screws that cuts its own thread directly into pre-drilled 6mm pilot hole, no anchor or plug is needed. Masonry screws are an excellent way to fasten any material to masonry...'

 

I need some hefty Torx concrete screws (M10, 120mm) to fix my wallplate (for the first floor) to the wall. 

Please would you help Confused of Lancaster?

[PeterW]

Yup they will do it. 

[joe90]

I used these to fix my stairs to the wall,  never used them before and was well impressed, nearly hurt my wrist with the torque.

[Declan52]

I used them for my door frames.  Really easy to drive in and out to get the frame perfect. 

[MikeSharp01]

My Experience with these screws is that the pilot hole is critical, don't use a worn out SDS drill, get a new one as factions of a mm make one hell of a difference to the torque you need to apply. Also once you start driving it in keep going until its fully in, stopping is also a problem I found, I did the last bit using a spanner rather than the impact driver. Good thing is they usually unscrew if required. 

 

[joe90]

And make sure the hole is deep enough, nothing worse than bottoming out thinking the fixing is tight.

[bassanclan]

If there are sheer forces then a thunder bolt might be better, if it's simply bedded on top of a block wall and to keep it from lifting then these will be fine and cheap enough from toolstation etc

[Russell griffiths]

Are you sure these are strong enough to take the load of a floor

i think I would be checking a few things. 

My first choice would be a sleeve anchor or old fashioned raw bolt. 

 

I have just put 200 of those concrete screws in my place and found it was a hit n miss affair if they took well, I would not want to use them in a critical location. 

[Russell griffiths]

like these. 

[Nickfromwales]

1 hour ago, bassanclan said:

If there are sheer forces then a thunder bolt might be better

This is the roof, so shear is deffo a concern. +1 to thunderbolt, chalk n cheese. 

 

12 minutes ago, Russell griffiths said:

Are you sure these are strong enough to take the load of a floor

i think I would be checking a few things. 

My first choice would be a sleeve anchor or old fashioned raw bolt. 

 

I have just put 200 of those concrete screws in my place and found it was a hit n miss affair if they took well, I would not want to use them in a critical location. 

Roof, but still significant shear. 

Agree that the concrete screws are hit and miss, but that’s more to do with what they’re being driven into than the fixing itself.   

@recoveringacademic Ian, is there anything between the timber and the concrete that you’re relying on for purchase? 

[Russell griffiths]

In Ian’s post @Nickfromwales he says they are for fixing his first floor. 

[MikeSharp01]

21 minutes ago, Russell griffiths said:

Are you sure these are strong enough to take the load of a floor

If, as I suspect, these are going to be mainly in shear, IE holding the plate on the wall, then a few M10 screws, provided they don't split the blocks, will have significant supporting capability. Typically in the order of 10Kn (appox 1000Kg) each.

Edited November 15, 2018 by MikeSharp01

[Nickfromwales]

1 minute ago, Russell griffiths said:

In Ian’s post @Nickfromwales he says they are for fixing his first floor. 

Cheers. ?. Sorry, last spoke with him re fixing the same but for his roof structure ?. 

My bad, scan reading strikes again. 

Point made though, as now even more critical.  

 

[MarkyP]

If we're talking abut fixing a ledger beam I would go for something beefier than concrete screws. I used M10 thunderbolts to fix a ledger beam to a blockwork wall. It supports floor joists in a stairwell, the thunderbolts work really well, rock solid and easy to use. Pilot hole in both beam and blocks, and then drive them in with a socket. I used washers to stop the head being driven into the beam.

[mvincentd]

+1 to thunderbolts, by default my structural engineer specced Hilti which were £6 each versus unbranded at the merchants for circa £1.  SE said smiling that they always spec those but never know what builders actually use.  Further research showed the Hilti were approx twice as strong (cant recall by what measure now).  Follow the instructions for pilot hole size versus thunderbolt size and be prepared to use a few sds bits rather than soldier on with a blunted one.

If you screw in using a pozidrive and things get tough try a spanner to get through the tight spot.....approx one in 8 of mine ran tight to rebar making things harder but i think i only actually had to give up totally on maybe 4 holes out of 130.

Framing screws do work ok in concrete, but i'd not feel safe using them for a wall plate.

[Onoff]

Resin anchored studding won't split the blocks...just fit to miss rafters / joists.

[MarkyP]

Thunderbolts apply very little or no expansion pressure as driven in, the thread is really very slight, only marginally bigger than the pilot hole. I think they'd be OK even with aerated blocks (though I would pause for thought with those as you only have to look at them a bit funny and they crack which is why I used lightweight aggregate blocks)

Edited November 16, 2018 by MarkyP

[MarkyP]

as an aside, I find that a can of compressed air is super handy for blowing the drilling dust out of pilot holes for concrete screws and thunderbolts. Saves having to over drill to account for the dust compacting at the bottom of the hole as you drive the fixing home. In fact they are handy for clearing dust and swarf form hard to reach places, I've used a few during my project.

 

Edited November 16, 2018 by MarkyP