Why Use Hot Lime Mortar Mixes
Since working on his own house, Tim commenced supplying Hot mixed lime mortar for builders and home owners and DIY enthusiasts for properties predominantly in the North of England but also many areas of England, Scotland and Wales.
The quick lime is produced in Cumbria and the Company tries to use local aggregates, but does make specialist mixes to order. From small beginnings the company now retails, promotes and trains builders and homeowners in the restoration of traditionally built properties.
New technology and traditional practices have come together to help restore our older houses. Over the last 100 years we, as a nation, have been trying to seal, tank, inject our properties and only caused more problems – houses need to breathe. With all the floods this century, the houses which are lime pointed, rendered and plastered are drying themselves out, the tanked ones have had to be stripped out and set off again.
The mortar needs to be softer than the stone. Cement in most cases is far, far harder than the stone, so the water is not able to escape back through the cement pointing/render. As a result it starts to go further into the wall and finally comes through into the living areas. Decorators have tried to put tin foil on the walls, builders have tried to put stud walls up or tank them but to no avail! Houses need hot lime mortar – it’s breathable and the house will dry itself out.
Advantages of Hot Lime Mortar Mixes
- High workability
- Increased productivity
- Fuller & compressed joints
- Can lay wet stones
- Cleaner work – no runs down the face of the work
- Able to build higher without squeeze
- Joint surfaces can be finished the same day
- Eliminates much of “touching up” afterwards
- Replicates original masonry
Pozzolan
Argical-M 1000 Pozzolan is helpful when applying hot lime mixes in damp, frost prone or exposed locations. The addition of Argical to hot lime mixes will increase compressive strength which helps to offer additional protection during the carbonation period.
Traditionally, volcanic ash, brick dust and other forms of burnt clays were used as additives in hot lime mixes and today this is refined in the form of Argical-M 1000. The term ‘pozzolan’ originates from the Italian town of Pozzuoli where volcanic ash was added during Roman times.
We recommend adding a pozzolan between 5% – 10% by volume depending on the time of year, exposure and use.
Quantity required for gauging into pre-mixed mortars:
- 5% by volume (1/20) – One tonne of mortar requires 12.5kg of Argical-M 1000
- 10% by volume (1/10) – One tonne of mortar requires 25kg of Argical-M 1000
Quantity required when making hot mix mortars on site:
- 5% by volume – For every measure of Quicklime added to the mix, add approx 20% of the same measure of Argical-M 1000
- 10% by volume – For every measure of Quicklime added to the mix, add approx 40% of the same measure of Argical-M 1000
