Stretch lime mortar?

[Freelin]

I have a house from 1928 where I have started renovating a room in the basement. The outer walls consist of natural stone and a thick layer of lime plaster. A previous owner later plastered the interior with some type of harder mortar, causing a lot of loose lime plaster behind it. However, I did not expect it to be so deep when I started chiseling, about 5 sqm, with a depth of 3-8 cm. I will use lime mortar to address this, but after checking the consumption per mm/sqm with retailers, I realize that this will require many bags and be expensive, with time being a factor since I can only plaster about 1 cm at a time. Now to the question: is it possible to fill in with, for example, shards from bricks, or perhaps gravel? (If I use hydraulic lime mortar) Does this affect the durability of the mortar or is it in any way unsuitable?

Kind regards, Fredrik

 

[cpalm]

If you want to get away cheaply, you can always mix your own bruk = lime + sand. But a few bags of bruk are not that expensive.

 

[heimlaga]

You get a phenomenal plaster if you mix regular dry-slaked lime, sand, and water, and then let the mixture sit and steep in airtight covered containers for a week or two before plastering.

 

[Freelin]

Thank you for your response. I did a calculation yesterday (hopefully incorrect) on a retailer's page it said 10 kg per 5 mm and sqm. If I calculate on an average depth of 50 mm, it would be 100 kg per sqm x5: 500 kg in total? Am I thinking correctly? I've been looking into buying just lime and mixing it, but can't find any of the "usual" chains that sell it.

 

[Claes Sörmland]

Optimize usually has [them] around here but they are a bit expensive.

 

[cpalm]

500 kg alltså? Tänker jag rätt?

That sounds quite reasonable. It would be 20 bags of 25 kg each at around 200 kronor per bag = about 4,000 kronor. Now the question is whether you indeed have an average thickness of 5 cm, as you have already noted, that's quite thick.