Purbeck stone grouting

[Wolfie9878]

Hi all

I’m currently on a project using 20mm purbeck stone the field tiles are 435x435 with a 3mm joint.
the architect Has specified a lime mortar grout.
I have used a nhl-5 and sand mix to grout before as the floor was breathable the tiles had 6mm joints though.
This floor isn’t a lime screed so doesn’t need to be breathable.
I would much rather use a modern cement based grout so I’m going to try and convince the architect it’s the route to take.!

most architects I have come across live by their specifications so I’m guessing he will stick to his guns.
Has anyone else had success with a 3mm joint in lime mortar?

I’m really after as much info as possible - to either support my case for a modern grout or to reassure me his spec will be fine

Cheers

 

[hmtiling]

Hi all

I’m currently on a project using 20mm purbeck stone the field tiles are 435x435 with a 3mm joint.
the architect Has specified a lime mortar grout.
I have used a nhl-5 and sand mix to grout before as the floor was breathable the tiles had 6mm joints though.
This floor isn’t a lime screed so doesn’t need to be breathable.
I would much rather use a modern cement based grout so I’m going to try and convince the architect it’s the route to take.!

most architects I have come across live by their specifications so I’m guessing he will stick to his guns.
Has anyone else had success with a 3mm joint in lime mortar?

I’m really after as much info as possible - to either support my case for a modern grout or to reassure me his spec will be fine

Cheers

Is it a solid floor without ufh?

 

[Wolfie9878]

Yes approx 30mm of latex over an old concrete floor then ditra.
100m2approx - no ufh

 

[hmtiling]

Yes approx 30mm of latex over an old concrete floor then ditra.
100m2approx - no ufh

I'd much prefer to use a cement based grout but imagine the lime/sand mix will be fine.

 

[Wolfie9878]

It’s the 3mm that worries me
I guess before modern grouts were available then this was the norm.

Would you suggest a kiln dried sand as it’s very fine?

 

[hmtiling]

It’s the 3mm that worries me
I guess before modern grouts were available then this was the norm.

Would you suggest a kiln dried sand as it’s very fine?

One for the elders here. @timeless john @Albert

 

[Albert]

One for the elders here. @timeless john @Albert

I must bow to my elders on this one, never used lime mortar just sand and cement, grout was mainly pure portland cement with the odd handfull of sand thrown in. Over to you John, maybe

 

[Time's Ran Out]

Would love to advise but out of my field of knowledge I’am afraid.

 

[Albert]

Maybe one of the stone men I think I remember Johnnyc grouting
with something similar

 

[Boggs]

I’m not sure if they can help in this situation but I spoke to a company called Stone Tech from Middlesbrough when I repointed a section of my house with lime mortar, they were very helpful.