Solid fixings of timber support into rendered concrete block.

[machtucker]

I’m going to bolt some 50x50mm section timber to the rendered concrete blocks to support the oak boards (see Pic). I’m going to need some secure fixings and screws/bolts that will be long enough to go through the 50mm timber and then into the fixing. Any recommendations? Only really used normal rawl plugs and screws. 
 

Many thanks,

 

Ed

[Conor]

120mm concrete screws... If you have an impact driver. If not, similarly long frame fixings.

[machtucker]

Yes I do have an impact driver. I did see Atlas screws on a review on the skill builder YouTube channel. Something like that?

 

[Mr Punter]

I like concrete screws but they can be more fussy than rawlplugs.  Concrete screws are quite dependant on substrate you are fixing to and drill diameter.  They are good if you are doing lots of the same - like battens etc.

[machtucker]

Well I’ll be fixing a wooden batten to the blocks fixing in 3 or 4 places. On top of the battens will be be 7 oak boards. Which are pretty heavy hence needing some secure fixings. 

Edited September 9, 2024 by machtucker

[machtucker]

1 hour ago, Mr Punter said:

I like concrete screws but they can be more fussy than rawlplugs.  Concrete screws are quite dependant on substrate you are fixing to and drill diameter.  They are good if you are doing lots of the same - like battens etc.

What do you mean when you say “fussy”?

[Mr Punter]

10 hours ago, machtucker said:

What do you mean when you say “fussy”?

 

If the hole is too large or small the screw can seize up or not tighten.  Also if you need to remove and reinsert the screw it does not behave as well as first time.

[machtucker]

On 10/09/2024 at 09:09, Mr Punter said:

 

If the hole is too large or small the screw can seize up or not tighten.  Also if you need to remove and reinsert the screw it does not behave as well as first time.

I see. I like the idea of just being able to screw in to the blocks.

[joe90]

Yes I used concrete screws to fix timber to concrete blocks as shuttering fir a garage base, just used a socket set but the hole has to be accurate diameter and clean.

[machtucker]

OK I will give them a go. Any recommendations on brand? I will need some 100mm long.

 

Something like these?

https://www.screwfix.com/p/turbo-tx-tx-double-countersunk-self-drilling-multipurpose-screws-6mm-x-100mm-100-pack/586vv

 

Edited September 11, 2024 by machtucker

[Conor]

 

OK I will give them a go. Any recommendations on brand? I will need some 100mm long.

 

Something like these?

https://www.screwfix.com/p/turbo-tx-tx-double-countersunk-self-drilling-multipurpose-screws-6mm-x-100mm-100-pack/586vv

 

Jeepers no. Something like this

 

https://www.screwfix.com/p/easydrive-tx-countersunk-concrete-screws-7-5mm-x-120mm-100-pack/9008h?ref=SFAppShare

 

Obviously you don't need 100... Might get cheaper options.

[joe90]

https://www.toolstation.com/masonry-torx-frame-fixing-screw/p60986

[FuerteStu]

Just a thought here, if you haven't built it yet. 

 

Every about putting a step in the blockwork? 

The bottom two courses could be wider blocks. Eliminating the need for screws completely. 

[machtucker]

17 hours ago, FuerteStu said:

Just a thought here, if you haven't built it yet. 

 

Every about putting a step in the blockwork? 

The bottom two courses could be wider blocks. Eliminating the need for screws completely. 

And in hindsight this would have been a good way of doing it, unfortunately the blocks are in and rendered....well, rendered badly!

Edited September 12, 2024 by machtucker

[machtucker]

21 hours ago, Conor said:

Jeepers no. Something like this

 

https://www.screwfix.com/p/easydrive-tx-countersunk-concrete-screws-7-5mm-x-120mm-100-pack/9008h?ref=SFAppShare

 

Obviously you don't need 100... Might get cheaper options.

Hmm, I selected masonry screws in the filter and the one I linked to came up. I guess that's not the right one then? I see yours specifically says concrete screw. Thanks for that.

[machtucker]

Going to go for these - amazingly they're significantly cheaper at B&Q

 

https://www.diy.com/departments/hardware/screws/DIY580655.cat?Length+(mm)=120&Suitable+for=Concrete

 

[joe90]

21 hours ago, joe90 said:

https://www.toolstation.com/masonry-torx-frame-fixing-screw/p60986

Why not these (as you don’t need 100)

[Super_Paulie]

just used those screws last night for a radiator batten into block work and they are my go-to for most medium to heavy jobs to be fair. Drill hole, clean it out, drive it in. Works every time.

[machtucker]

4 minutes ago, joe90 said:

Why not these (as you don’t need 100)

Ahh I misread. I thought that price was for 1! Doh! That is good value. I think I will go for the 122mm versions as the batten is 50mm thick and render about 10mm thick so that will leave 62mm into the concrete. Or do you think the 102mm will be fine?

 

Cheers.

 

[joe90]

33 minutes ago, machtucker said:

I think I will go for the 122mm versions

Why not.

[Conor]

 

Ahh I misread. I thought that price was for 1! Doh! That is good value. I think I will go for the 122mm versions as the batten is 50mm thick and render about 10mm thick so that will leave 62mm into the concrete. Or do you think the 102mm will be fine?

 

Cheers.

 

You need 120mm. The concrete screws need a bit more depth compared to other anchors. I've used 100s of the things over the course of our build. 

 

Or, if you want to make life easier... Forget the 50mm batten and just fix each board on with something like this with a 5x50mm pan head screw.

 

https://www.screwfix.com/p/simpson-strong-tie-reinforced-angle-brackets-galvanised-30mm-x-55mm-25-pack/652tj?ref=SFAppShare

 

 

 

[Gus Potter]

Hi all.

 

There is lots of talk about concrete screws. But it is apparent to me as an SE that you have no idea of the loads that you may be supporting and the different behavoir of the substrate you are fixing into.

 

Unless you are aware of this and the compressive loads from above, masonry bonding and the fact that a lot of concrete screws off the self are not stucturally rated then you need to shut the (expletive deleted) up as your comments are dangerous.. and stop giving advice that could miss lead the novice to Build HUb.

 

if you want to suggest other fixings then I'm ears..

 

[joe90]

@Gus Potter In this particular case we are talking about a shelf in a pizza oven, hardly structural.

[Gus Potter]

Aye ok.. true but what gets my goat is there are loads of folk advising on structural fixings and it is clear to me that they have no clue about the implications. 

 

 

 

 

[saveasteading]

I used to use and dpecify concrete screws but don't now.

The hole has to be exactly right to a fraction of a mm or the thread won't bite properly.

So the exact bit, without hitting obstructions.

I'd much rather use a quality plug and my own choice of screw.

 

It's only a wooden shelf.  Hence such a long discussion.