lime mortar mix.

[robgil]

ive been told that none hydraulic is best for this instance , i need to bed down some wall plates onto a clay lump wall. i also need to rebuild some of the wall with second hand clay lump bricks that i sourced locally and i was going to use the lime mortar for this also. i may even need to bed in an oak lintel above the window as the window frame at the moment is holding up the roof. :shock:

 

[Tom]

I used NHL 3.5 for all our work, inside and out. Our house is quite exposed and open to the elements. I understand that Hydraulic Lime is best for damp or wet situations, which I why I chose it. It's good to work with and has given very good results. Our mix has always been 3:1 by volume.

 

[Jon Maine]

ive been told that none hydraulic is best for this instance , i need to bed down some wall plates onto a clay lump wall. i also need to rebuild some of the wall with second hand clay lump bricks that i sourced locally and i was going to use the lime mortar for this also. i may even need to bed in an oak lintel above the window as the window frame at the moment is holding up the roof. :shock:

The argument is that non hydraulic remains softer and probably more breathable too. You shouldn't have problems using hydrated or putty lime.

 

[robgil]

ok , so , hydraulic lime will set quicker and harder?

 

[Jon Maine]

ok , so , hydraulic lime will set quicker and harder?

Certainly can be quicker, hardness or compressibility is in the number i.e. 2 less hard slower setting described as feebly hydraulic, 3.5 as moderately hydraulic and 5 eminently hydraulic.

It has a naturally occuring pozzolan in it which causes a chemical reaction which sets it before full carbonation.

You can add pozzolans to other limes to achieve the same effect.

There is an argument that more pozzolan = less breathability.

See http://www.buildingconservation.com/articles/pozzo/pozzo.htm

 

[robgil]

lovely , thankyou. i dont think breath ability is a huge issue here but hardness perhaps is , although i cannot make it any harder than the wall below it.

 

[Tom]

After plenty of research and asking questions over and over again, that's what I came to understand.

 

[Jon Maine]

lovely , thankyou. i dont think breath ability is a huge issue here but hardness perhaps is , although i cannot make it any harder than the wall below it.

Sounds like NHL3.5 is the easiest choice for you.

 

[Flyfisher]

>wet sand can occupy up to 30% more volume! You've covered yourself with the 'up to' phrase but if we are talking anywhere 30% I don't believe you. With a coarse, sharp sand I doubt there would be a measurable difference. The water fills the spaces between the grains and any film separating grains would be negligible.

I agree. I can't see how water can cause sand to expand in volume - it will fill the spaces between the sand grains. Imagine filling a bucket with dry sand. Now add water. I reckon you could keep adding water until the water overflowed the bucket, not the sand.

 

[Flyfisher]

I use hydrate unless I have some left over and then I turn it into putty so it keeps.

Me too.

Just be careful when using lime putty and very wet sand that the result isn't too sloppy (or keep your sand out of the rain ).

 

[Louis Henry]

If you're rich use lime putty sold in tubs, if you're a professional who needs to complete a job quickly to make any money use hydraulic lime, if you're poor and patient mix up hydrated lime.

 

[MdB]

Just be careful when using lime putty and very wet sand that the result isn't too sloppy (or keep your sand out of the rain ).

Yes that is an issue I've come across too. Its one of the reasons why I prefer to use hydrate.

If you do end up with a too sloppy mix, you can always leave it overnight to settle and then pour off the excess water from the top.

 

[Flyfisher]

If you do end up with a too sloppy mix, you can always leave it overnight to settle and then pour off the excess water from the top.

Glad to hear I'm not the only one to have done this.