Natural Hydraulic Lime - Faster Setting times?

[Woody3]

We are a few weeks away from starting our extension. We are going to be using lime (NHL 3.5) mortar (ratio of sand:lime - 3:1).

Having looked on various websites, there seems to be quite a few manufacturers of NHL - Tarmac, Singleton Birch, Hanson, etc.

Some of the limes are imported, others are sourced from Lincolnshire and Derbyshire. "Fair enough, I'll source locally", I initially thought. I then came across this statement on Mike Wye's website:

We are Main Distributors for Hanson Castle Natural Hydraulic Limes...NHL 3.5 (moderately)... These quality NHLs are made in France and fully meet the requirements of BS EN 459:2001... These French hydraulic lime mortars are relatively quicker setting and have a higher final setting strength compared to the UK NHLs

.

Does anyone have any experience with the Hanson Castle NHL's? Do they "go off" much faster than UK sourced Limes? Will I get back the extra cost in materials in reduced labour times?

Any info would be gratefully received!

Cheers,

W.

 

[plasticpigeon]

I used Singleton Birch NHL 5 for a limecrete floor, and it was really nice to use. I found roundtower which a local yard stocked, much less fatty and pliable to use by comparison. I think I've used Hansen, but my favourite was Singleton Birch so far. I really don't know about setting times, I don't think it is particularly important is it unless you are wanting to walk on a lime floor quickly?

 

[skier-hughes]

the numbers relate to strength settings after a certain time, so any NHL5 should be of a similar strength after 28 days, see page 2
http://www.mortar.org.uk/documents/miadata21-mono.pdf

 

[88v8]

Speed matters if one is pointing, for instance. Used St Astier, went off very quickly, faster than my stonemasons were accustomed to, by the time they came to the churn-brushing it was already too far gone, really.
Ultimate strength, no idea, but one has to get used to the individual characteristics of the lime with which one is working.

Ivor

 

[tobydog]

Speed matters if one is pointing, for instance. Used St Astier, went off very quickly, faster than my stonemasons were accustomed to, by the time they came to the churn-brushing it was already too far gone, really.

Ivor

Totally agree. I got a bag of St. Astier NHL 3.5 from Anglia Lime to plaster on a couple of sole plate brick plinths. When I went back with the churn brush a couple of hours later to finish them off later it was too late, despite spraying! I originally had visions of going back to them the next day!. On the next plinth I chose to use putty which was far more forgiving. Still workable after a few days. In hindsight I should have used putty from the outset because I wasn't after strength.

 

[Zebra]

I used Singleton Birch NHL 3.5, ratio of 2 soft, 1 sharp, 1 lime. Didn't have the problem of it going off too fast, and even in the summer (covered with wet cloths) I was able to bash it nicely the next day.

 

[Woody3]

Thank you for the replies.

The reason I ask is, the slower the mortar goes off, the less courses of stone can be laid within the day, ultimately meaning more man hours.

If I remember correctly, a wall constructed with cement mortar wall can be built to a maximum height of 1.5m per day. A wall constructed with lime mortar can be built to a maximum height of 0.5m per day. Does the Hanson Castle NHL 3.5/French Lime, allow the maximum height of a wall built per day to be comparable to a cement mortared wall?

Does that make sense? :?

Might give Mike Wye's a ring tomrrow...

 

[Zebra]

Ah, so you want it to go off quickly.
Don't know. I was repointing, not building. But as far as I understand, there is like a sliding scale from cement mortar on one end, to putty mortar on the other, with all the NHLs inbetween, and for every gain in breathability, there is a loss in speed of set and hardness. So probably, fewer courses can be laid in a day with NHL 3.5 than with cement, but more than with putty. If they say the French NHL goes off faster than UK NHL, then it must be more towards the cement end of the scale, but not necessarily on a level with cement.
I imagine the manufacturers technical department would be able to advise.

 

[stuart45]

Thank you for the replies.

The reason I ask is, the slower the mortar goes off, the less courses of stone can be laid within the day, ultimately meaning more man hours.

If I remember correctly, a wall constructed with cement mortar wall can be built to a maximum height of 1.5m per day. A wall constructed with lime mortar can be built to a maximum height of 0.5m per day. Does the Hanson Castle NHL 3.5/French Lime, allow the maximum height of a wall built per day to be comparable to a cement mortared wall?
.

With stone work it depends on how the wall is constructed. If it's done with really big joints like used on a lot of new build housing with Random Rubble you can't go very high in a day, even with cement mortar.

 

[michael]

Good luck on trying to source locally produced hydraulic limes as they seem to be very difficult to find nowadays.
Singleton Birch it would seem now source their limes from Portugal from a company called Secil Argamassas.

http://www.naturalhydrauliclime.com/index.php?display=whats_going_on&mode=news&nid=96

And as you say the Hanson Castle NHL’s are from France and I’m guessing the Tarmac limes are also from France as that company is now ‘Lafarge Tarmac’ and Lafarge based in Paris is an industrial company specialising in concretes and cements.

In addition I believe the St Astier NHL’s are produced in the Dordogne as is a product I often use to repair the ‘Roman cement render’ on my property namely ‘Vicat Prompt’ natural cement.

It would seem that Natural cement producers have completely disappeared from the UK but can anybody advise on the remaining home grown NHL producers? You mention Woody that there are still some producers in Lincolnshire and Derbyshire. I would be interested to know who these are and who distributes their products.

 

[Woody3]

http://www.britishlime.org/about/our_members.php

Lafarge Tarmac owns "Buxton Lime", which I assume comes from one or more of the limestone quarries in and around Buxton???

Another producer of UK sourced lime is: http://www.hyperlimeco.com

http://www.lime-mortars.co.uk/lime-mortar/hydraulic/NHL3.5/25kg - Lime, quarried from the UK

So supposedly UK limes are out there...