Sandstone laying - not bonding

Patio flagstones (slabs), concrete flags, stone flags including yorkstone and imported flagstones.
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liquidsmoke
Posts: 6
Joined: Wed May 25, 2011 4:02 pm
Location: cambs

Post: # 64870Post liquidsmoke

Hi,
I have just layed my first patio with indian sandstone from 'Stonemarket'. I used a wet mortar bed with SBR in the mix, and also coated the backs of each slab with SBR/cement slurry just before laying. However I've found a few slabs that are not bonded properly; and I can lift them up. They don't rock, and the bed underneath is solid; so I guess they would probably be OK if I just pointed now with Rompox Easy.

However being a bit of a perfectionist I would prefer to bond them down again. My question is whats the best adhesive to use? Needs to be strong, water and frost proof! I'm thinking Gorilla Glue ot No More Nails Ultra...?

Quick response appreciated, as I'd like to get this done and jointed this week :)

Cheers!

DNgroundworks
Posts: 1951
Joined: Sat Dec 06, 2008 10:28 pm
Location: Preston, Lancashire

Post: # 64873Post DNgroundworks

to do it properly, you would have to dig up the bedding mortar again, using adhesives wont work, or you could use a neat cement slurry poured on to the existing bedding layer and put the flag back on to that, but thats just a temporary fix.

In reality the flags dont need to bond if they are not at free edges, as long as they are fully supported and not rocking then all is good, and why may i ask did you lift them up?

lutonlagerlout
Site Admin
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Joined: Fri Aug 04, 2006 12:20 am
Location: bedfordshire

Post: # 64878Post lutonlagerlout

curiousity killed the cat I'm afraid
dan is 100% correct
any you have lifted now ned to have a new bedding layer under them

LLL
"what,you want paying today??"

YOUR TEXT GOES HERE

DNgroundworks
Posts: 1951
Joined: Sat Dec 06, 2008 10:28 pm
Location: Preston, Lancashire

Post: # 64935Post DNgroundworks

On a recent job we lifted and relaid about 40m of indian stone, and the bloke whose house it was had stuck a few back down with fixing foam lol, and man where they stuck!

After reading how cookie does his work, we have just laid an indian stone patio on a semi dry bed, doused down last thing with a house pipe, anyway we are easi pointing today and the flags as presumed sound unstuck, Question for cookie - is this deemed ok? Is that the norm?

I usually use a wetish mix to aid adhesion but i thought id try cookies methods as he seems to know what hes on about :)

liquidsmoke
Posts: 6
Joined: Wed May 25, 2011 4:02 pm
Location: cambs

Post: # 64938Post liquidsmoke

Thanks for the responses. It didn't take any effort to lift the ones that are not bonded down properly. KNowing how thin some of these slabs are; 15mm-30mm, It didn't seem to a great idea to leave them unbonded, so I wanted to know which were bonded and which weren't...most are fine, but some werent bonded.

I'm not quite sure on your logic here; your telling me they can be stuck down temporarily with a cement slurry. But also telling me they don't need to be stuck down at all as long as they're not rocking?

So I should just leave them unbonded then your saying...or?

liquidsmoke
Posts: 6
Joined: Wed May 25, 2011 4:02 pm
Location: cambs

Post: # 64939Post liquidsmoke

PS: I tried Gorilla Glue on a couple of slabs the other night; they seem now very solid.

EDIT: i just actually tried with all my (puny) strength to lift one of the slabs up that I had glued down 2 days ago. it doesn't budge.
i have 10 in total that I've found to be loose. They seem random. Although it rained heavily after I layed a few and they were all loose. maybe that says something...

I've Gorilla glued the other 8 or so that were loose down. So I'll post back in a few weeks when I find out if they're still solid :)

lutonlagerlout
Site Admin
Posts: 15184
Joined: Fri Aug 04, 2006 12:20 am
Location: bedfordshire

Post: # 64943Post lutonlagerlout

the time to look for rockers is after they have been pointed
most flags/slabs will come up with little force if pulled
but the idea is that they take downward loading,not upward
LLL
"what,you want paying today??"

YOUR TEXT GOES HERE

haggistini
Posts: 1405
Joined: Thu Sep 27, 2007 10:29 am
Location: South Wales
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Post: # 64957Post haggistini

I finished a job today ( two more to go by Sunday....) and yesterday the customer had only tried to rock them with his feet the evening after I laid them !!! I only needed to relay 2 thank feck. I just didn't need that shite first thing this morning!
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DNgroundworks
Posts: 1951
Joined: Sat Dec 06, 2008 10:28 pm
Location: Preston, Lancashire

Post: # 64980Post DNgroundworks

i was just saying that if your that bothered you could pour a cement slurry to help bond it, cookie mentioned it once on here.

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