Two part jointing compound on cast stone steps

[lesley2]

Hi,
Please can you advise me on the best jointing compound to use for repointing some cast stone steps (haddonstone). I would like to use a two part compound like Romex D1 but would like to use it like a traditional mortar rather than sweeping it in (as this wouldn’t be possible on steps). I would also be concerned about how the cast stone would react to Romex being swept in.

Would Romex D1 be suitable to mix up like a mortar and apply into the cleared out joints using two trowels before being struck? Or is there another two part compound (or anything else) that would be more suitable?

Thanks.

[Tony McC]

It *can* be used as a trowelled mortar, but it's not easy and you have to tape-up any vertical joints to keep the compound in place for the initial cure.

The substrate needs to be soaking wet, too, which further complicates the job.

It would be worth having a word with the tech advisors at Romex or at NCC StreetScape to see if they have a "tweak" for jointing steps.

[lesley2]

Hi Tony - thanks for your reply.

I contacted NCC StreetScape who advised against using any of their products. The cast stone steps have joints of c.6-7mm. I guess the only remaining method will be to point with sand and cement (silver sand and snowcrete) with SBR added.

The previous pointing hasn't lasted well so I was hoping to use something a bit more resilient. Would exterior tile grout be an option?

Thanks

[Tony McC]

Yes: you could use an exterior tile grout, but again, check with the manufacturer first.

I *do* like it when a supplier advises NOT to use their product. Far too many retailers will sell you anything just to hear the till ring, but it's always the sign of a reliable and trustworthy trader when they advise you to seek some alternative rather than just grab your money.