# Forum Home Renovation Brickwork  Mortar Mix - Sandstone External Wall

## Sir Stinkalot

Hi All, 
I am wanting to tackle the relatively simple task of removing an old box air conditioning unit from a sandstone wall (1870's). The unit is located below a window and the opening to be filled is only about 600 x 900mm.  
On the radio the other day they had a stone mason talking about repairing old sandstone walls and the need to get the mortar mix right. Unfortunately I was in the shower at the time and found it difficult to hear the details. From what I did hear he mentioned the use of a lime mortar, but not the lime found at Bunnings. I have tried to do a search and came across the following at Tasmanian Heritage Council info: 
" Lime mortar mixed in the traditional way from rocklime should be used. Lime mortars are also more flexible than cement and will self repair for minor movement cracks. This will save you time and money in the long run. *Should I make my own lime mortar?*WARNING - This process can be dangerous and it is recommended that trained trades people carry out this work." 
Can anybody please provide me some insight on the best way to tackle this task. 
Cheers 
Stinky

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## johnc

> Hi All, 
> I am wanting to tackle the relatively simple task of removing an old box air conditioning unit from a sandstone wall (1870's). The unit is located below a window and the opening to be filled is only about 600 x 900mm.  
> On the radio the other day they had a stone mason talking about repairing old sandstone walls and the need to get the mortar mix right. Unfortunately I was in the shower at the time and found it difficult to hear the details. From what I did hear he mentioned the use of a lime mortar, but not the lime found at Bunnings. I have tried to do a search and came across the following at Tasmanian Heritage Council info: 
> " Lime mortar mixed in the traditional way from rocklime should be used. Lime mortars are also more flexible than cement and will self repair for minor movement cracks. This will save you time and money in the long run. *Should I make my own lime mortar?*  WARNING - This process can be dangerous and it is recommended that trained trades people carry out this work." 
> Can anybody please provide me some insight on the best way to tackle this task. 
> Cheers 
> Stinky

  You should be able to find a recipe, it does spit a bit and is dangerous when first mixing, but worth the effort.

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## Sir Stinkalot

Thanks John .... for some reason I missed this thread when I did a search: http://www.renovateforum.com/f210/li...recipe-110967/

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## intertd6

Off memory I think boral bricks has a masonry down load with mortar mixes & includes lime mixes for restoration.
regards inter

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