Anyone Used NHL 5 for Repointing?

[Rich1972]

Is it too hard for stonework? I want 'chaux gris' as I find the chaux blanc too white, but the local 3M store only has St Astier Pure (Grey-ish) Lime as an NHL 5.

I want a grey lime, NHL 3.5, with no added cement! Is that so hard?!

[:@]

[Dave&Olive]

hi ok

             it`s the sand that dictates the colour of the mortar not the lime ...you need to get some of the dark red sand  most good builders merchants have it and stick to 3.5 lime

Dave

[Théière]

What is your wall made of? if it is flint or granite you can use NHL5 if its tuffau the 3.5 is better.

Grey lime? why it sucks all the light out of the room, re-done ours the other year much more cheeful and requires less light bulbs so greener too.

As other poster said use a darker sand.

[Rich1972]

Thanks for the replies.

The wall is just your standard pale cream limestone, and it's the exterior walls I'm doing. I used a dark brown sand with LeFarge white lime to do some running repairs and, as I said before, after I'd brushed down the mortar I was left with a VERY white residue on the stones. I've talked to my French builder/roofer about this a lot and he said that he never uses white lime, as it's too blinding in direct sunlight, but prefers grey lime with red sand and a small bit of cement. I'm not using the cement and I can't get 'red' sand, only the brown sand and the only grey lime I can find is NHL 5. I'm looking for something that is going to give me a golden mortar, sort of the colour of a light demerara sugar.

Rich

[Théière]

Hi Rich, yes the NHL5 grey will have cement in it to get it to the 5 grade. We discussed this at length on a forum the other day.

http://www.completefrance.com/cs/forums/1539023/ShowPost.aspx

 

[dr orloff]

[quote user="teapot"]

Hi Rich, yes the NHL5 grey will have cement in it to get it to the 5 grade. We discussed this at length on a forum the other day.

http://www.completefrance.com/cs/forums/1539023/ShowPost.aspx

 

[/quote]

That's not how it works.  The chemical composition of the source material and temperature variations in the production process will determine the hydraulic property of the lime so produced.  NHL5 should not contain cement.  NHL 5-z indicates the presence of a pozzolanic additive (normally cement).

 

 

[Théière]

[quote user="dr orloff"][quote user="teapot"]

Hi Rich, yes the NHL5 grey will have cement in it to get it to the 5 grade. We discussed this at length on a forum the other day.

http://www.completefrance.com/cs/forums/1539023/ShowPost.aspx

 

[/quote]

That's not how it works.  The chemical composition of the source material and temperature variations in the production process will determine the hydraulic property of the lime so produced.  NHL5 should not contain cement.  NHL 5-z indicates the presence of a pozzolanic additive (normally cement).

[/quote]

That's not how it should be, True, however in real life the manufacturers do it the easy way and state cement added. Especially the grey which is the colour achieved when lime is taken to a higher temprature for cement production than for lime production

 

[dr orloff]

[quote user="teapot"][quote user="dr orloff"][quote user="teapot"]

Hi Rich, yes the NHL5 grey will have cement in it to get it to the 5 grade. We discussed this at length on a forum the other day.

http://www.completefrance.com/cs/forums/1539023/ShowPost.aspx

 

[/quote]

That's not how it works.  The chemical composition of the source material and temperature variations in the production process will determine the hydraulic property of the lime so produced.  NHL5 should not contain cement.  NHL 5-z indicates the presence of a pozzolanic additive (normally cement).

[/quote]

That's not how it should be, True, however in real life the manufacturers do it the easy way and state cement added. Especially the grey which is the colour achieved when lime is taken to a higher temprature for cement production than for lime production

 

[/quote]

I find that difficult to believe. Could you provide me of an example of an NHL 5 pure chaux with added cement.

I use St Astier limes.  NHL 5 and NHL 3.5. They state that they are pure.  How do you know different.?

 

 

[Théière]

[quote user="dr orloff"][quote user="teapot"][quote user="dr orloff"][quote user="teapot"]

Hi Rich, yes the NHL5 grey will have cement in it to get it to the 5 grade. We discussed this at length on a forum the other day.

http://www.completefrance.com/cs/forums/1539023/ShowPost.aspx

 

[/quote]

That's not how it works.  The chemical composition of the source material and temperature variations in the production process will determine the hydraulic property of the lime so produced.  NHL5 should not contain cement.  NHL 5-z indicates the presence of a pozzolanic additive (normally cement).

[/quote]

That's not how it should be, True, however in real life the manufacturers do it the easy way and state cement added. Especially the grey which is the colour achieved when lime is taken to a higher temprature for cement production than for lime production

 

[/quote]

I find that difficult to believe. Could you provide me of an example of an NHL 5 pure chaux with added cement.

I use St Astier limes.  NHL 5 and NHL 3.5. They state that they are pure.  How do you know different.?

[/quote]

I use the same and they are pure, its the tradifarge style products that have the added cement,  and as you have said and I frequently forget to add to my typing the z branded bags.

Please don't misunderstand me the thread was about the grey lime which is usually a mix and not pure.

[dr orloff]

[quote user="teapot"][quote user="dr orloff"][quote user="teapot"][quote user="dr orloff"][quote user="teapot"]

Hi Rich, yes the NHL5 grey will have cement in it to get it to the 5 grade. We discussed this at length on a forum the other day.

http://www.completefrance.com/cs/forums/1539023/ShowPost.aspx

 

[/quote]

That's not how it works.  The chemical composition of the source material and temperature variations in the production process will determine the hydraulic property of the lime so produced.  NHL5 should not contain cement.  NHL 5-z indicates the presence of a pozzolanic additive (normally cement).

[/quote]

That's not how it should be, True, however in real life the manufacturers do it the easy way and state cement added. Especially the grey which is the colour achieved when lime is taken to a higher temprature for cement production than for lime production

 

[/quote]

I find that difficult to believe. Could you provide me of an example of an NHL 5 pure chaux with added cement.

I use St Astier limes.  NHL 5 and NHL 3.5. They state that they are pure.  How do you know different.?

[/quote]

I use the same and they are pure, its the tradifarge style products that have the added cement,  and as you have said and I frequently forget to add to my typing the z branded bags.

Please don't misunderstand me the thread was about the grey lime which is usually a mix and not pure.

[/quote]

I thought you were referring to the grey-ish St Astier NHL 5 mentioned by the op.

To the Op:

 

You can get ready mixed lime/sand mixes in umpteen shades - Point P do them and try your local builders merchants.  St Astier do a range.  They are pricey though.  Alternatively you could try colouring the lime with natural pigments -eg ochre (mix in bulk to avoid colour variations).

Personally I like the colour achieved by lime and golden river sand.

 

 

 

[dr orloff]

[quote user="Rich1972"]Thanks for the replies.

The wall is just your standard pale cream limestone, and it's the exterior walls I'm doing. I used a dark brown sand with LeFarge white lime to do some running repairs and, as I said before, after I'd brushed down the mortar I was left with a VERY white residue on the stones. I've talked to my French builder/roofer about this a lot and he said that he never uses white lime, as it's too blinding in direct sunlight, but prefers grey lime with red sand and a small bit of cement. I'm not using the cement and I can't get 'red' sand, only the brown sand and the only grey lime I can find is NHL 5. I'm looking for something that is going to give me a golden mortar, sort of the colour of a light demerara sugar.

Rich


[/quote]

There shouldn't be any residue at all on the stones.  The Lafarge NHL3.5z and NHL5z limes contain cement which makes them set quickly (too quickly imho).  Maybe try a pure lime - NHL 3.5 and see if it gives different results.  My pointing comes out a nice off white and I don't use dark sand - just ordinary goldeny river sand (sharp sand).  Some friends used very yellow sand and the result was extremely creamy looking pointing.  Brushing back should remove all the unwanted mortar from the stones.  If you wish I'll try and post a photo of my pointing (internal so far but should give a good idea).

 

[pachapapa]

The Z in the specification should be a capital Z in accordance with EU Norms; the use of lower case may give spurious "google searches". NL refers to a Natural Lime in accordance with EU Norms; in french frequently called a "chaux aérienne". NHL refers to a Natural Hydraulic Lime in accordance with EU Norms. The 2-5 refers to the strength of the lime. On a separate thread I mentioned that the TradiFarge product  and it's generic equivalents contain added cement; I now appreciate from development of this thread that "cement" should be more clearly expressed as Portland Cement to prevent confusion with other cementitious material frequently added to concrete mixes for different reasons.

On another thread I mentioned the use of "pozzolanic" material by the Romans at Herculaneum; the often crucial Z factor with a Natural Hydraulic Lime; fortunately for the Romans there were plentiful supplies on the slopes of Vesuvius close by. Later a LOT closer for those who have visited the Archaeological Excavations to the south of Naples on the way to the Amalfi  Peninsula.

Whilst the Z does indicate the addition of a CEMENTITIOUS material to the lime , it does NOT indicate the addition of PORTLAND CEMENT to the lime; either in it's white or grey colouring.

The colour of a pointed stone wall can be due to the colour of the constituent sand or to the addition of a pigment giving the desired colour to the jointing.  A word of caution ONLY natural pigments must be used as industrial pigments are too intense and are only suitable for concrete floors.