Cracked slabs

[Launchbury]

Untitled

• Launchbury
• 23 Oct 2010
• 1

I layed these few slabs to stand the BBQ on - Marshalls Richmond.

The day after I layed them I could see a line running across 3 slabs, I have looked really closely but there is no sign of a crack in the slabs surface. However, I did hit them hard with the rubber hammer so I'm pretty sure the lines are indicating cracks.

As they are held in place very well (on a flat mortar bed and solid pointing), will they be alright. Or is it only a matter of time until they fail? Should I swap them out whilst I'm still in the mood or leave them?

Many thanks.

 

[Alastairreid]

Looks like you have fractured them! i would change them while you are in the mood as they look unsightly and will only get worse when the frost arrives.

 

[tomhat]

I agree with alastairreid.

I always go by the motto: "if a jobs worth doing, its worth doing well"

 

[imamartian]

for a different perspective (i'm not a pro), think of them as smaller, less uniform slabs.. and if they're bedded soundly, i think you'll be fine. However, they do look unsightly.... i'd probably re-lay them myself!!

 

[r896neo]

I'm not trying to imply your an idiot because some flags are very difficult to tell and others are obvious but are you sure those few are the right way up? It's common to get lines like those that are casting marks and look like cracks but are not, however as implied by my question these are almost solely found on the underside.

 

[Launchbury]

Definately laid the correct way up, they were very obvious top and bottom.

 

[WabbitPoo]

Yes, those Richmonds are the lowest of the lows in terms of quality - quite good for BBQ or bin areas, though. And yes, you've cracked 'em. The frost will make it worse, so take the plunge now and replace them. If you are having to hit your slabs hard, then the mix you used is too stiff or you had too much under the slabs in the first place.

 

[imamartian]

The frost will make it worse, so take the plunge now and replace them.

can i just play devil's advocate and question why the frost will make a cracked slab worse? Some slabs are laid with a mortar pointing, and others closely butted... surely, a cracked slab justs reflects a closely butted slab. And as long as they're bedded correctly with no gaps under, or no movement when walked on, the frost will not affect them (unless of course they are on an open edge to a patio)?

 

[studips]

well, water could get into the crack and under the slab easier which might blow them in heavy frost i guess, but you're right, it won't damage the slabs any further.

it's still got to me replaced as it will collect dirt and look 'orrible

next time buy a rubber mallet

Richmond might be the Marshalls' budget slab, but the still aren't cheap (or is it just me getting old?)

 

[imamartian]

i think frost will blow the face off of a porous brick, but it doesn't affect slabs really.... i think.

but i agree, base too stiff if you're needing to belt 'em enought o break!!

 

[Launchbury]

The slabs were £2.20 incl of VAT - the cheapest slab Jewsons had, they are 450 x 450.

I used a rubber mallet but as Wabbitpoo pointed out; too much mix under the slab and mix was probably a bit too stiff - and I did hit them hard.

However, they were laid on a solid bed and I pushed and pressed the pointing in place, ratio 3:1.

There is no sign of any cracking on the face of the slab so I thought although the slab has been fractured, in effect it is just like to 2 seperate slabs butted up hard together. If frost would get in the crack why wouldn't frost get into any of the joins between the whole slabs?