Para bolts pulling through

[James94]

I have a stud buttress wall that has to be fixed to the block work as stated in the plans, only problem is when i tighten them up they pull back through. 

https://www.screwfix.com/p/fischer-fxa-throughbolts-m12-x-146mm-20-pack/49007?tc=IT7&ds_kid=92700048793290424&ds_rl=1249413&gclid=EAIaIQobChMIop_Q1Zfo8wIV5YFQBh16OgdFEAQYAyABEgL7ivD_BwE&gclsrc=aw.ds these are the bolts in question.

I've tried a smaller masonry bit but still happens, does anyone have any suggestions?

Regards  James

[dpmiller]

says they're specifically for solid concrete, *not* blocks?

[James Newport]

I think @dpmiller is on to something. The Q&A section on screwfix says

Quote

Thanks for you enquiry, Only concrete means only poured or cast
concrete, the FXA is not suitable for concrete blocks or masonry.
I would use a resin anchor in to concrete block.

 

Edited October 26, 2021 by James Newport

[James94]

A lesson learnt, waste of £15. Can anyone recommend any certain ones.

regards. James

[Conor]

Thunderbolts.

 

https://www.wburton.co.uk/product/m12-x-100mm-thunderbolts/

 

You'll need a half decent impact wrench or driver.

[markc]

Thunderbolts are good as long as they are not close to the edge of the blocks, chemical anchors are better because they effectively stabilise the block and hold it together as opposed to trying to bust the block open

[Mr Punter]

Frame fixings

 

https://www.screwfix.com/c/screws-nails-fixings/frame-hammer-fixings/cat840010#category=cat840068&productdiameter=10_mm&page_size=100

[James94]

Thanks for all the suggestions and advice, think were going to go with the chemical anchors.

Regards  James

[wozza]

The first fixing you tried are for solid concrete / brick - the metal collar is an interference fit / tight fit when inserting - then when tightening the conical end forces it to spread in the hole.

 

I have recently used some chemical fixings and will reach for them most times now.

[Andehh]

Resin fix a threaded bar into it! Just make sure you get it right the first time....once bonded in they aint never coming out

 

https://www.screwfix.com/p/rawlplug-r-kem11-175-kit-styrene-free-polyester-resin-175ml/4100R?tc=VA6&ds_kid=92700048793290424&ds_rl=1249413&gclid=EAIaIQobChMI1KfD2vr28wIVFaWyCh2zsQn_EAQYASABEgIW-vD_BwE&gclsrc=aw.ds

Edited November 1, 2021 by Andehh