A long way to the top if your gonna rock and roll! - Rocking flags on a rock solid bed

[Baron Greenback]

Hi there, trying not to go nuts about this one, I have dug to a 350mm depth (dug a bit deep), have about 200mm of compressed (whackered) hardcore, and 100mm or thereabouts of mortar mixed 6:1 Sharp sand and Cement. Went for the damp method, got it all down, made the dumb mistake of walking on it too soon "it felt solid enough...Doh!" and now I have some parts of the patio that are rockin! The bed is Rock solid though and I was considering using a strong builders mortar 3:1 and simply re-laying the rockers on a combed layer of mortar, with a bit extra under the corners that rock similar to how you would if you were to tile a wall. The jointing mortar is going to be - Rompox Easy - and I am sealing the indian limestone slabs prior to the Rompox stage with - Smart Seal Ultra-Sealer Dry Finish - want to do it before the jointing as I want the Rompox to remain porous and allow drainage. Do you guys tink that I will be OK stabilising the stones in this way? I really cannot see the base moving and surely it is more a case of eliminating voids at this stage? Thanks for your feedback! BG.

[Pablo]

If you don't have the heart to cut the bed below the rockers out then you can make up a very wet mix and float the flag level with them or better still use SBR and cement adhesive to set them in. DO NOT USE Rompox Easy it's crap and by crap I mean totally sh#te and it's impossible for 100mm of bedding to be porous enough anyway. The Rompox D1 2 part system is very good and not much more money but I'd rarely use anything other than good old sand and cement although plenty on here rate easipoint very highly. Make sure the sealant is applied to absolutely bone dry flags on a warm day otherwise they'll go white.

[lutonlagerlout]

easipoint is sand and cement pablo
just finely graded and evenly batched
I would either dig out and relay the rockers completely
or try a small amount of very wet grout (cement and water mixed neat) in the joint adjacent to the rocker if its only slight
good luck
LLL
ps lovin that nickname :;):

[Pablo]

easipoint is sand and cement pablo

no shit Sherlock

[seanandruby]

Was your 'hardcore' small enough and plenty of fines, or dtp1? If there were voids and you walked on it you displace some of the mortar into the deeper voids causing rocking. Always best to use dtp1. It depends how severe the rocking, as to how you do the snagging.

[Bob_A]

easipoint is sand and cement pablo
just finely graded and evenly batched

So why is it so expensive.

[Bob_A]

Not exactly rocking but I could detect the smallest of movement on some of my flags if I stamped on them.

I mixed cement and sbr together approximately 1:1 by volume.
Carefully pour it into the joints and clean up any spillage immediately (this is sooooo important)
Give it a while and let it settle then top up again. Keep topping up but obviously leave some room for the pointing.
This was my DIY method and it worked for me but it may not in all cases.

As regards Rompox Easy that's what I used and found it to be rubbish.
I reckon being porous is its downfall.
First of all some of it shrank so the Rompox rep called Ray gave me some more.
Now I just have suffer it being continously dirty and eroding away when washed.
I reckon this product is on par with Geofix. Do a search to find out what others think of that!

[Baron Greenback]

SBR? what is that then?

[Bob_A]

SBR Bond is a white liquid which has numerous uses as an admixture primer bonding agent and sealer. Polymer Emulsions of this type have been used extensively over the last 20 years by the building industry as an admixture for cement and concrete applications including repair and renovation surfacing of floors and bonding generally. It contains anti-foam to control the density of cementitous mixes. Greatly improved adhesion to a wide range of substrates including dense concrete steel tiles etc. Mixes may be applied in much thinner sections Excellent resistance to water and water vapour A high level of resistance to salt permeation Much improved toughness and flexibility Reduced surface dusting of concrete Greatly improved resistance to many chemicals- ideal for use in dairy parlours etc. Reduced water: cement ratio for equivalent workability Improved frost resistance -SBR Bond is also freeze thaw stable.

Bet that impressed you.
You can get it from Screwfix, Toolstation and Builders merchants
If no one local then Toolstation will defiver it for free http://www.toolstation.com/shop....8

[Baron Greenback]

Yes Bob that has impressed me a great deal, sounds like the stuff I am looking for, how far does it go?

[Bob_A]

Difficult to say how far it goes.
Why not buy 5L from Toolstation for £17.56 delivered and see how you get on.
If it doesn't work then you've only wasted less than £18 and at least you'll know that you'll have to lift the flags and rebed.
If it does work then you can guage how much more you'll need.
That's the beauty of free delivery.

[stehurt@hotmail.com]

Not exactly rocking but I could detect the smallest of movement on some of my flags if I stamped on them.

I mixed cement and sbr together approximately 1:1 by volume.
Carefully pour it into the joints and clean up any spillage immediately (this is sooooo important)
Give it a while and let it settle then top up again. Keep topping up but obviously leave some room for the pointing.
This was my DIY method and it worked for me but it may not in all cases.

As regards Rompox Easy that's what I used and found it to be rubbish.
I reckon being porous is its downfall.
First of all some of it shrank so the Rompox rep called Ray gave me some more.
Now I just have suffer it being continously dirty and eroding away when washed.
I reckon this product is on par with Geofix. Do a search to find out what others think of that!

Hi,

Would you use SBR for the screed bed you lay the slabs on as well?

Thanks Steve

[Tony McC]

If it's just a patio, and you're using a bond bridge primer slurry, there's no great need for SBR to be added to the bedding mortar.