For the latest academic research papers onthe use of lime in construction from around the world, take a look at the Building Limes Forum

A significant point of note is that Hydraulic limes, known as NHL should never be used on a historic cob buildings since it’s porosity drastically reduces over time and may lead to the trapping of moisture on a similar level as cement based materials. Trapped moisture can rapidly cause decay in sensitive earth mortars, cob and soft bricks and stone. More dangerous though, is the false comfort that lime has been used therefore the situation is okay. Old Stone buildings, specifically in Devon and the south-west are commonly built with earth mortar between the stones which makes them as vulnerable to problems as a cob construction since the earth can rot leaving what is effectively a very loose dry stone wall.

We have a deep understanding of the materials used historically and how the techniques used to make them can affect their ultimate characteristics in the context of construction. We believe that the in most circumstances the historic methods are the best methods.After all, these techniques and materials are time severed for thousands of years.

We make a lot of our materials from scratch, including lime mortars, lime renders, lime plaster, lime skims, lime putty, lime wash and mass cob.

COB

Mass cob is sourced as locally as possible to the project so that it is as close original material as feasible.

LIME

We bring quicklime down from Wales to slake into the various forms of building lime.

If hydraulic characteristics are required in our mortars, then a pozzolan is added in small quantities so as not to noticeably reducing the natural free-lime content and its moisture handling qualities.

With lime, the precise method of manufacture can have a significant bearing on the durability work ability and weather resistant qualities of the final material. Our lime materials are made in small batches so if the process doesn’t go exactly to plan we can dump it and start again.

POZZOLANS

Pozzolans used today are generally waste products from industry and range from brick dust to ground blast furnace slag. Historically, volcanic ash(From mount Vesuvius)and or siliceous rich mineral deposits we used. There are many variations on the source material and mixing recipes, but they are essentially silica-rich materials which, when mixed with Calcium Hydroxide (Slaked lime) react to provide cementitious, or hydraulic qualities. Romans used pozzolans to make concrete which can still be seen in good condition 2000+ years on.

Interesting: The name Pozzolan, is derived from the name Pozzuoli, a city in Italy, which is the original source of volcanic ash,from Mount Vesuvius, used in construction. The same volcanic ash that buried the ancient city of Pompeii also helped the Romans create the first known concrete in the world.

TIMBER

We use natural oak, chestnut or larch laths to provide keys for our lime renders and plasters on stud work, partition walls, beams or wattle and Daub.

Seasoned Oak is the wood of choice for structural timber repairs such as roof truss repairs on cob or stone houses.

Air dried oak is used for replacing lintels in cob or stone walls as its natural movement is closer to the materials in the rest of the building than concrete or steel.

Our bespoke joinery, windows and doors etc, are built using joinery grade timber of what-ever type is desired or required.

For more detailed explanation of the differences in traditional lime products see our Traditional Lime mortars