Pointing with lime

[trevorbayliss]

http://www.travisperkins.co.uk/Natural-Hydraulic-Lime-NHL-5-25Kg/p/721731

I want to use this product to do some pointing with on a fairly exposed wall. It is stone construction.

I have never pointed with lime before, only cement. I think it is 2:1 with the sand and lime.

How long does it take to set though ? That is my worry. What happens if we get rain the next day because it is very rainy at the moment. I hope to get a rain free day at some point in the next few weeks.

 

[mattice]

wrong time of year for lime pointing sorry. Late spring early summer best before it gets hot. It won't set.

 

[trevorbayliss]

ok and how long to set if done in spring then ? What happens if it rains the next day ? Does adding some cement to the mix help the setting ? If i did this would i loose the breathability of the lime qualities ?

There was a product called limebond sold by travis, but i can't see it anymore.

 

[stuart45]

If using NHL lime don't use any OPC with it. Mix for 20 minutes in the mixer, leave for 20 to fatten up, then mix again for a couple of minutes. Don't put too much water in at the start as it will get wetter as it gets air into the mix. NHL does cure by hydration as well as absorbing CO2, so it does cure better than an air lime externally.
Which one are you using 3.5 or 5?

 

[trevorbayliss]

I think i would go for 5 as it is stronger. I need to point a chimney as well.

I will be doing all mixing in a bath and so by hand.

What is OPC? I assume it is cement.

 

[stuart45]

OPC is ordinary portland cement. Make sure it's well mixed, needs much longer than portland. Make the joints flush, then hit them with the churn brush next day.

 

[trevorbayliss]

I am pointing stone so the faces are not straight like bricks. So was going to use pointing iron. Possibly a curved one which i have used on brick before. This means my joint will curve inwards a bit. I am not a builder by the way. Just advanced diy.

 

[stuart45]

Metal brings laitance to the surface which hinders the breathing. It's best to expose the aggregate with the churn brush.

 

[trevorbayliss]

ok, just seen a video on tube and it is a bit clearer now.