# Forum Home Renovation Brickwork  Mortar mix for Besser blocks

## fdip

I built a water trough/pond with besser blocks recently using 5:1:1 mortar mix. All good, but the top capping seem a little fragile. I have been building a deck, benches around the water feature. I just tapped the top capping at one end and a crack appeared along the mortar/brick and can now lift the block out of position.  
See pic 
Should I use a stonger mortar with a higher cement ratio for the capping or a high strength brick glue/compound?

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## fdip

Any brickies home relaxing with a beer after today's heat?  
Your input would be mostly appreciated. 
Cheers

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## Blocklayer

Being solids, the joints will crack easily. 
I'd use some bondcrete http://www.bondall.com/_webapp_5362/BONDCRETE (or similar product)
And a bit more cement. 
I did a big (block) house years ago for a bloke who insisted a full (40kg) bag of cement went in every batch. It was like toothpaste, but 18 years later and it hasn't cracked at all. Probably not a good idea for (clay) bricks though
.

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## fdip

Thanks Blocklayer, would you suggest I remove all the capping, clean up the blocks and start fresh using Bondcrete?

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## Blocklayer

Is this thing supposed to hold water? 
If it is, I'd pull all the blocks down, clean up the mess, throw the blocks away and use H blocks with concrete core fill and steel reo. 
But yes, if it's just a wall with no pressure against it, clean the old mortar completely off first and re-lay with bondcrete. 
You'll also find it takes a while for the mortar to really cure. Wetting the blocks each day for a few days can help speed this up.
In the wet season here, the mortar cures faster because of the frequent rain. This can make it safer to core fill, so in the dry season I often used to give the walls a good soaking when finished, so the core fill wouldn't crack or break the mortar joints.
.

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## fdip

It is going to hold water as a reservoir for ther water feature. It will be fibreglass sealed for 100% waterproofing. These are H blocks, with the centre filled with mortar. Only the capping are solid blocks. It is a lot stronger than a blueboard structure widely used by the professional industry. Got the seal of approval by local pond specialists. 
I will remove the top capping and use mortar with Bondcrete. Should be ok. 
Thanks for your help.

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