Suitable Fixings for Screwing Into Paving/Cement?

[Doug99]

Hi All,

I've just had some new paving laid to which I am seeking to secure a wooden arbour. I've spoken with the paver to ensure that there is a full bed of cement underneath the paving stones to take the fixings.

But what fixings would be suitable for the job?

Paver suggested 'Thunderbolts' - Do I insert these bolts so that they screw into both the paving and cement base, or just the cement? How long should I leave the cement to harden before drilling it?

The paving slabs seem sturdy enough - Castcrete Autumn Gold - so assume they wouldn't split if drilled/screwed.

Any advice would be appreciated.

Thanks

 

[Newboy]

Thunderbolts or resin fixings will do - don't use anything like expanding anchors or the slab is likely to split.

Go easy drilling the slabs and stay clear of drilling near the edges

 

[noseall]

Success will largely depend upon luck, particularly if you have more than one hole and they are close together and close to the edge of the slab. The chances of the slab splitting are high.

Concrete screws (thunderbolts) are probably the best bet. They will take a bit of screwing in though.

 

[cjard]

Cordless impact driver will be your friend if you have any number of them to do..

I'd do it after the mortar cures (grey, hard, been down a few weeks) because the vibrations from hammer drilling the slab might separate the slab from the mortar or to a lesser extent, weaken the curing mortar by disturbing he crystalline structure hat is forming to cure it

 

[WabbitPoo]

Doomed to fail. Yes the slabs might be on mortar but that's not enough to take any lifting or shear stresses.

 

[Doug99]

Thanks all, so the plan is:
1. Position the arbor so that the footings are clear from the slab edges.
2. Wait a couple of weeks for the cement to cure fully.
3. Drill slabs and cement.
4. Screw thunderbolts to both the slab and the cement.
5. Avoid impact drivers.

Cheers

 

[WabbitPoo]

See my post above. Or ignore, as you seem to have so done.