Hydrated Lime

[Gallah]

Had some lime putty stewing away for some time but need to double the quantity to make enough lime mortar for internal chimney repair.I threw away the old bag with the make on,it was green&white.Just picked up a bag of Cemex Rugby hydrated lime,the label on which points more towards agriculture than building....has anyone used that particular make for creating lime mortar and if so how were the results?

Did a dummy run with the old lime putty,3 parts lime putty to 1 of sharp sand.Leaving the bricks for a week and then will see how strong or flaky the mortar is.May have to use a catalyst as I understand both lime and sand are often too pure nowadays.Don`t really want to use any cement but also did a 9 parts sharp sand,1 cement,1 lime putty mix and it set well but too grey for the job.I need to retain the breath-ability,flexibility and look....or else I would just muck about with cement.

Any advice would be appreciated.Thanks.

 

[Ricke21]

i had to use lime to rebuild a listed building. Not really sure on the make of lime, the bags were white with blue print. The gage was 8 soft 3 lime and 1 cement. The mix looked to be week and yellow but set well. Hope that helps a lil

 

[stuart45]

General rule of thumb is non hydraulic lime for internal work and hydraulic for external.

 

[theoldun]

Lime putty is made from slaked quick lime, not hydrated lime, although you can make a crude line putty from hydrated lime if you make it up 6 weeks before you need to use it and you will need a pozzolanic additive to achieve a decent set. Even then it will be rubbish.
You need Hydraulic lime NHL3.5 either premixed or pure and add your own sand.
Do your self a favour if it is only for a chimney repair use sand lime cement.
oldun

 

[Gallah]

Thanks everyone,thought I`d missed something!Looks like lime-cement-sand mix it is then.....better to be safe than sorry

Reckon these tubs of hydrated lime putty I inherited 15 years ago were used for the plastering of an internal wall,which still looks very sound....but different stresses than a ton of bricks with only 12mm veins of weak mortar between them!