Cracked Pointing on top of wall above expansion joint

[self builder 123]

Morning

I have a concrete block on flat ( 215mm thick ) wall which is finished on top with pre cast concrete coping stones. The wall has expansion joints every 6m.

Near one particular expansion the pointing keeps cracking right the way across from front to back - has been pointed twice now with sand and cement.

I am assume that it is connected to the location of the expansion joint, but it is hard to imagine that the wall would ever actually move !! The foundation is continuous right the way through.

Is there another product I could use rather than just sand and cement, so as to give the 12mm wide pointing some flexilbility ?

Cheers.

 

[Static]

The movement joint should continue through the capping stones, so just replace the mortar joint over the movement joint with a flexible joint.

 

[self builder 123]

Hi

I am looking to replace the cracked pointing with a flexible material.

The original pointing was a cement : sand mortar which simply cracked - see the attached picture.

Untitled

• self builder 123
• 18 Jul 2010
• 1

I was thinking about re-pointing with a weaker mortar ( 6:1 mix ) or either a lime mortar ?

Would lime mortar offer the necessary flexibility ?

I look forward to your replies.

 

[freddiemercurystwin]

No, Mastic.

 

[self builder 123]

Hi

Was thinking about inserting some fibreboard that I have to take up most of the void and then seal over with polysulphide sealant / mastic.

Sounds like we have a plan !

Many thanks.