Frost lifted newly laid patio!

[Evilweasel]

Hello Chaps

First post, and it's a tale of woe that I hope with your advice will have a happy ending...

Earlier this year I lifted my shoddy builders 5 dab per slab laid patio, and relaid it on a compacted sub base, on a bed of 4:1 mortar. Really nice job I thought, nice runoff, mixed size slabs, and much more stable than before. This was October. I can't remember the exact timing, but I decided that due to the poor weather not to point the concrete riven slabs until the new year. Of course over the last few weeks we've had a very cold snap, and this morning, looking out through my patio doors, I saw some broken looking mortar in between the slabs. I went out and had a check, and at least 60% of my slabs are now loose - caused by frost.

I'm not going to do anything about it this year, but in the spring, I don't want to have lift all my slabs and break up 10x5m of mortar bed to have to relay them over again.

I've had an idea where I can lift the slabs alone, and relay them on a slurry of cement, water, and PVA - essentially 'gluing' the slabs back on to the mortar bed, and in turn, not lifting the level of the slabs.

Would this work, and if not, any other suggestions involving the least effort for the best result? Oh - and I promise next time to point the slabs in straight away.....

Many thanks

John

[seanandruby]

Welcome john. Because of the exceptional harsh cold spell last year and now this year, paving etc is being tested to the limit. It seems you are'nt alone with frost heave. I'm afraid a slurry bedding will be no good at all. You will need to lift flags, take out the bedding and replace it. Obviously it will be a waste of time doing it before the spring.

[Evilweasel]

Thanks Sean

Not the answer I was hoping for really. All that has happened is that the slabs have come adrift from the bedding - the bedding itself is sound, but the flags have sort of 'come unstuck' from the mortar.

If I really do have to lift all the flags, and bed, and start again it'll be a depressing winter looking at my - on the face of it - lovely patio, knowing that it will have to come up.

Is there really no way to 'stick' them back to the mortar? No sort of 'glue' that could be used to bond the slabs back down? We've put a man on the moon damn it!

Many thanks anyway....

[Bob_A]

The profeesionals on here work to very high standards, you won't see them recommending fixes that might not work.
Have a read of this, it might work. If it not Sean's fix will definitely work
http://ext.pavingexpert.com/cgi-bin....U]

[Evilweasel]

Hi Bob

Yes - I know that the best way will be to lift it all up again, and is most likely the option I'll be forced to take when I give the thing a close inspection in spring...

However you've offered a chink of hope in your suggestion, so it may give me a bit of comfort over the coming months.

Sorry to see I'm not alone in this. So I guess the best option is not to lay any sort of patio in the Autumn as there's a risk that this will happen?

[haggistini]

a large section of tar lifted outside my mothers house which has been down for years , i am currently relaying a really botched patio and there was a layer of white frost about 200mm down its been very cold and a freeze thaw action can break ,split or lift anything wait till spring and get stuck in

[Tony McC]

Slurry fixes are OK for one or two loose flags, but for larger areas, they just don't work as the slurry will move to low points or voids and leave everything uneven.

And slurries don't use PVA. Check other threads about SBR Slurries.

[simeonronacrete]

Hi

If you prep the surface, back to a solid substrate, you can then lay a minimum thickness 6mm Ronafix mortar and bed the slabs onto this.

Feel free to give us a call or see Ronafix Site Batched Bedding Mortar.