The Brew Cabin

Posted: **Thu Aug 13, 2015 9:27 pm**

Help needed:

I have Laid blue limestone flags 900x600mm x30-45mm thick, on a semi dry paving sand/cement bed, 50-80mm deep. With granite cobbles 100x100mm between, and along the side of the flags. I did not apply a bond bridge.

The semi dry bedding has set, but some of the flags have come loose, (or sound loose) would applying a bond bridge (SBR & cement) fix the problem permanently ? (Lift each flag carefully, apply bond bridge, and reposition) Or should I rebel the flags, in wet sand /cement mix?

All advise welcome...

Posted: **Fri Aug 14, 2015 7:57 am**

If you are confident of the bed structure then yes a bond should work. You need to place the paving back in exactly the same orientation and position as they came out.

You may find that the bond bridge will make the relaid slabs slightly proud so getting the mix is essential, single maybe double cream consistency.
Try gently lifting a slab immediately after laying you'll know straight away if you've got it right.

There is always though, that possibilty of more slabs coming loose over time but hopefully as you've used large heavy slabs it may not be an issue.

Posted: **Tue Aug 18, 2015 11:47 am**

Blue limestone is one of those types of flag that is virtually impermeable (it's not really, but it seems that way when laying it!) so a bond bridge is to be highly recommended to ensure adhesion to the bed.

Lifting the loose flags and then priming before re-laying *might* work, but far too often the flag never quite settles properly on the original bed, so it's often worth the effort of breaking out the old bed and putting in new. That way, you can be sure of getting the flag to the correct level, firmly bedded and properly held in place.

The Brew Cabin

Paving flags - bond bridge - Applying a bond bridge for loose flags ?