Slab laying methods

[Jwoodgardenmaintenance]

Hi all

 

Just out of curiosity how do you lay your slabs? I always lay mine on a dry 4-1 mix  but a lot of people use spots as well what are the advantages / disadvantages?

 

Jack

[Ratman]

Always lay on a full bed, spots can cause staining then you end up with a patio looking like a dice once weathered. I personally mix 3 - 1 ((each to their own though) and use plasticiser so they key. Pointing up is again your choice, standard mortar or alot use the modern sweep in stuff or resin based pointing now.

 

Example of spot staining below

 

[Jwoodgardenmaintenance]

7 minutes ago, Ratman said:

Always lay on a full bed, spots can cause staining then you end up with a patio looking like a dice once weathered. I personally mix 3 - 1 ((each to their own though) and use plasticiser so they key. Pointing up is again your choice, standard mortar or alot use the modern sweep in stuff or resin based pointing now.

 

Example of spot staining below

 

I didn’t know about that staining thank you showing me I use dry mix just for the simple fact I can screed a good size area then lay then keep going like that I used to brush dry mix 2-1 for the pointing but I bought a tub of pave-tuff £30 all in and it just looks so much fresher plus the empty tubs are really handy for storing bits so haven’t bothered going back to dry mix

 

Jack 

[Ratman]

I’m not a fan of laying on a dry bed as i’ve known it ti wash out sometimes underneath and cause the flags to rock in time, but thats just me personally. Plenty have done it with no issues of course, guess a lot depends on your prep work before finally laying.

[Jwoodgardenmaintenance]

4 minutes ago, Ratman said:

I’m not a fan of laying on a dry bed as i’ve known it ti wash out sometimes underneath and cause the flags to rock in time, but thats just me personally. Plenty have done it with no issues of course, guess a lot depends on your prep work before finally laying.

It’s the way I was tought by my grandfather when i was younger (he was a stone mason) so it has always worked for me i always dig out for a 6” base of type 1” - 1 1/2” of dry mix then whatever the slab is but once I’ve dug out I’ll compact the soil put weed control in then 2 x 3” layers of type1 compacted never had it wash out yet but it could happen as you say 

 

Jack 

[william127]

Full wet bed for me, 5 soft, 5 sharp, 1/2 bag of cement.

Up to this autumn I've preferred wet mix 2, 2 1 soft, sharp cement pointing but the new brush in regardless of the weather jointing mixes are what I'm using now, as I dont loose time if its raining,  and they do make a nice crisp finish, especially on single colour paving??

[Ratman]

One part of my outside area i did last year, 40 to dust whackered, then full bed of mortar, flags laid, then pointed up with sika dark grey brush in.

 

 

[kevinjohnsonmbe]

Nobody mentioned a bonding bridge yet!

 

Cement mixed with adhesive to form a wet slurry (consistency of pancake batter) brushed onto back of slab before laying. 
 

Its esp relevant for porous slab - granite as a case in point - it improves adhesion and reduces the potential for staining to draw through from underside to top side. 
 

My local quarry did this vid which shows the potential issues with spot staining. 
 

 

 

[Ratman]

Nobody mentioned a bonding bridge yet!
 
Cement mixed with adhesive to form a wet slurry (consistency of pancake batter) brushed onto back of slab before laying. 
 
Its esp relevant for porous slab - granite as a case in point - it improves adhesion and reduces the potential for staining to draw through from underside to top side. 
 
My local quarry did this vid which shows the potential issues with spot staining. 
 
 
 

I use SBR in my mixes for everything, flagging, block work etc, apart from pointing up as its adhesion is so good that if you get it on the face of your flags or faced brickwork its a twunt to get off if it gets chance to dry [emoji35]

[kevinjohnsonmbe]

4 minutes ago, Ratman said:

I use SBR in my mixes for everything, flagging, block work etc, apart from pointing up as its adhesion is so good that if you get it on the face of your flags or faced brickwork its a twunt to get off if it gets chance to dry

That’s the monkey! 
 

SBR & cement powder mixed to a wet slurry & painted onto underside just before they go down.  
 

Are you saying you put SBR in the bedding mix?