Lime pointing question

[Burdekin]

I’m touching up the lime pointing at the front of our cottage and a mate has recommended 2.5:1 mix and it’s too white. What’s the standard mix and would 3.5:1 be okay and make it more yellow?

 

[gaz1]

it depends on what your mixing and the materials that your using

with lime it depends on the grade of lime that you have

then depends on which sand your using

then you have to decide on how fine of a mix you want that comes with the choice of sand that your using

most wont know the mix reference you have said

so 2 lime, 5 sand and 1 cement 2.5:1 ratio mix
3 lime will make it more whiter

 

[arther dailey]

it depends on what your mixing and the materials that your using

with lime it depends on the grade of lime that you have

then depends on which sand your using

then you have to decide on how fine of a mix you want that comes with the choice of sand that your using

most wont know the mix reference you have said

so 2 lime, 5 sand and 1 cement 2.5:1 ratio mix
3 lime will make it more whiter

interesting , can I ask why do you add cement to a lime mix ? I thought lime was supposed to give more flex/breathability without cement , thanks

 

[AVI_8]

I just repointed my wall a few weeks ago, used 1 part NHL 5 lime, one part sharp sand and 2 parts builders sand, worked out well.
I’ll take a picture so you can see the colour as long as you don’t slag my inexperienced pointing skills!

 

[AVI_8]

The wall I did myself, the other picture is of the Ashlar sandstone on the front of my house which as you can see was done by a sandstone restoration company who knows what they were doing, they added a colouring agent to make it appear a bit more yellow in colour.

 

[Burdekin]

I just repointed my wall a few weeks ago, used 1 part NHL 5 lime, one part sharp sand and 2 parts builders sand, worked out well.
I’ll take a picture so you can see the colour as long as you don’t slag my inexperienced pointing skills!

Thanks, will try 3:1 tomorrow.

 

[AVI_8]

Just to add that I wouldn’t add any Portland cement into it if it’s sandstone, my house had previously been repointed incorrectly with cement, it actually damaged it in some places, if driving rain gets behind it and freezes in winter it will expand and crack the sandstone, this happened on my house, it cost several thousands of pounds to get it all out and repointed in a traditional manner with lime mortar, luckily the company I got were able to replace the bits that had cracked off with a repair patch which when coloured is now barely noticeable. Cement is good on a new build not on a house built a hundred years ago.

 

[Gareth J]

Which lime are you using? NHL? 3.5?

I think NHL5 is reserved for very harsh environments, maybe that's you but otherwise a 3.5 might be sufficient...

I had a load of stonework done by a local company that does a lot of traditional building work. They used NHL3.5, which is much more brown than the grey/white of cement/hydrated lime. And a very yellowy aggregate. The result was a nice tone without the grey of cement or much white limeyness. Will take a photo tomorrow if it helps.

 

[Burdekin]

Which lime are you using? NHL? 3.5?

I think NHL5 is reserved for very harsh environments, maybe that's you but otherwise a 3.5 might be sufficient...

I had a load of stonework done by a local company that does a lot of traditional building work. They used NHL3.5, which is much more brown than the grey/white of cement/hydrated lime. And a very yellowy aggregate. The result was a nice tone without the grey of cement or much white limeyness. Will take a photo tomorrow if it helps.

It’s 5. Cottage is right on the North Sea in north east Scotland.

 

[Burdekin]

Just to add that I wouldn’t add any Portland cement into it if it’s sandstone, my house had previously been repointed incorrectly with cement, it actually damaged it in some places, if driving rain gets behind it and freezes in winter it will expand and crack the sandstone, this happened on my house, it cost several thousands of pounds to get it all out and repointed in a traditional manner with lime mortar, luckily the company I got were able to replace the bits that had cracked off with a repair patch which when coloured is now barely noticeable. Cement is good on a new build not on a house built a hundred years ago.

Thanks. Not adding any cement. I’m just patching up the pointing that was done 5 years ago, maintenance rather than redoing it. It’s some sort of granite and was built from the stone on the sea front in front of the cottage. Cottage is older than 250 years old.

 

[AVI_8]

Thanks. Not adding any cement. I’m just patching up the pointing that was done 5 years ago, maintenance rather than redoing it. It’s some sort of granite and was built from the stone on the sea front in front of the cottage. Cottage is older than 250 years old.

View attachment 456683

Lovely character cottage!
And yes as Gareth questioned and as I was advised by the supplier I'm on the exposed west coast of Scotland 5 would be best, it’s dried in really solid.

 

[gaz1]

interesting , can I ask why do you add cement to a lime mix ? I thought lime was supposed to give more flex/breathability without cement , thanks

with period propertys you dont add cement to it what so ever

 

[julianf]

Without looking it up, nhl 3.5 at a 3:1 would seem normal, although a harsh environment is mentioned.

I guess if you are using nhl5, and want to colour match, get the right colour sand, and add the lime to suit?

re: lime to cement - its a different type of lime, added as a platiciser

 

[AVI_8]

I’m no expert, just have an old property which I did a ridiculous amount of research on, I was advised by a local company to use NHL 5, both myself and the OP live in exposed Scotland environments, all of the you tube videos I watched recommend 3.5 but when I talked to local suppliers they said NHL 5, I went with the advice of the local supplier. There’s nothing between my house and the coast, and looking at the OP’s house there’s nothing between it and the North Sea. Perhaps if you live in Birmingham or Sheffield 3.5 is fine, I would say just go with what’s advised.

 

[Gareth J]

I’m no expert, just have an old property which I did a ridiculous amount of research on, I was advised by a local company to use NHL 5, both myself and the OP live in exposed Scotland environments, all of the you tube videos I watched recommend 3.5 but when I talked to local suppliers they said NHL 5, I went with the advice of the local supplier. There’s nothing between my house and the coast, and looking at the OP’s house there’s nothing between it and the North Sea. Perhaps if you live in Birmingham or Sheffield 3.5 is fine, I would say just go with what’s advised.

I completely agree. Driven rain in exposed locations needs belt, braces and hat.

Wall hung cladding, slates in Cornwall, wriggly tin on a lot of Scottish isles! To take the horizontal component out of the equation is next level. Though east coast should get enough breaks in weather to cope without.

 

[arther dailey]

with period propertys you dont add cement to it what so ever

thanks , whats the benefit of adding cement to it otherwise though ?

 

[gaz1]

its not cement as its a trick question cement is too new and cement seals not breaths

if you want to seal but breath you need to look through roman cellars wine cellars as therse are underground structures

roman concrete outlasts new concrete by 1000s of years as new concrete only has a shelf life of 50 years

sea concrete being the best

 

[julianf]

thanks , whats the benefit of adding cement to it otherwise though ?

Its not that you add cement to lime...

Again, different types of lime -

NHL you would not add cement to, but...

You may add hydrated lime to a predominantly cement mix as a plasticiser.

Ie hydrated lime is added to cement for a function, rather than cement is ever added to a predominantly lime mix.