Benefits of Lime
- caring for buildings
Lime has been used as the binder in mortars, plasters, paints and floors for centuries, it is usually blended with an aggregate to make mortar and an aggregate and fibre to make plaster/render.
Lime has a proven track record, it has been used in architecture since 12,000 B.C. and there are plenty of examples from antiquity that still survive today (how many modern buildings will be standing in the next hundred or even thousand years?).
We were cement-free in the UK up until the 1920s, so buildings pre-dating this would primarily have been constructed of lime - it is staggering when we actually stop to think about all of the stone and brick buildings we see around us every day like Victorian Terraces, Georgian streets, farm houses, churches, chapels, barns, village halls, castles, cathedrals, stately homes, abbeys - all built without cement - and those that have been repaired and cared for appropriately are still standing.
It is often thought that lime is not as 'strong' as cement and so has no place in building today, but lime has other qualities, qualities that have helped traditional buildings to survive (very sustainable having buildings last centuries!) and qualities that are now encouraging a new generation of builders/developers to incorporate lime in their new builds - creating healthier, more sustainable homes.
- lime products are vapour permeable - this is important in solid wall buildings as it means that any moisture is allowed to escape from the walls, this helps to control condensation and damp within the building (most modern renders, plasters, mortars and paints are impervious, trapping moisture leading to problems such as condensation, mould growth and even degradation of the fabric of the building such as timbers rotting, bricks/masonry crumbling).
Damage caused by 'hard, impervious cement pointing' to stonework - lime is 'softer'
and 'Vapour permeable' which protects the stone and hence the building/structure.
- lime mortars are relatively flexible and will accommodate some movement in a wall without cracking, each joint of lime mortar is like a mini expansion joint. If lime cracks it can ‘self-heal’ when exposed to air unlike their modern counterparts which are harder and hence more brittle. This allows movement and flex within structures (just look up at the beautiful domed ceiling in a great cathedral, only achieveable because of this quality!) whilst allowing them to remain upright - often in earth quake zones, the 'traditional' buildings constructed of lime remain standing whilst modern 'cement' buildings fall down as they are more brittle.
- lime mortars are sacrificial - so any salt or frost damage occurs in the mortar not in the more expensive components like brick/masonry.
- caring for the environment
We, as well as others, have been keen over the last few years to highlight the potential lime has within new builds as a cement replacement. The use of cement has grown enormously, by 2020, world production is expected to top 3,500 million tonnes, three times the level used just a decade ago. 10% of worldwide Carbon Dioxide emissons are attributed to the production of cement (this is comparable with the aviation industry). The cement industry itself has taken measures to reduce the impact but there are things we can all do like considering alternatives whenever we think about using it in our buildings/structures - the range of limes now availble (in terms of strength) as well as the work we have been doing in developing 'systems' has made the possibility of this much greater including in new timber-framed buildings, new 'solid wall' constructions, warm roofs and limecrete floors. We are always delighted to hear from any new potential projects and applications to see if we can assist.
-lime is burnt at a lower temperature than cement and so has an immediate energy saving of 20% (although kilns etc are improving so figure do change). A standard lime mortar has about 60-70% of the embodied energy of a cement mortar. It is also considered to be more environmentally friendly because of its ability, through carbonation, to re-absorb its own weight in Carbon Dioxide (compensating for that given off during burning and so forms the famous lime cycle).
- lime mortars allow other building components such as stone, wood and bricks to be reused and recycled because they can be easily cleaned of mortar/limewash and re-used.
- lime enables other natural and sustainable products such as wood (including woodfibre, wood wool boards), hemp, straw etc to be used because of its ability to control moisture (if cement was used these buildings would compost!).
- caring for health
- lime is considered to be less harmful to human health than many of its modern counterparts:
■ lime plaster is hygroscopic (literally means ‘water seeking’) which draws the moisture from the internal to the external environment, this helps to regulate humidity creating a more comfortable living environment as well as helping to control condensation and mould growth which have been shown to have links to allergies and asthmas. The American College of Allergies suggest that 50% of all allergies are aggravated or
caused by our ‘polluted’ internal environment, thus lime creates a healthier living space.
■ lime plasters and paints are non-toxic, therefore they do not contribute to indoor air pollution unlike many modern paints.
- caring for local economies and communities
Finally, lime products create a beautiful, lively, unique aesthetic that no modern material can replicate....well we think so....
Ty-Mawr - the home of the founders and owners of Ty-Mawr Lime Ltd as well as the head office and training centre - restored using traditional fat lime mortars, plasters and limewashes.
New timber-frame build using glaster, woodfibre boards, sheep's wool insulation and wood wool boards - please email us for system builds at firstname.lastname@example.org