What to do with Earth / Mud Mortar Walls?

By Andy the stuff doer

Our walls in the Whitby cottage are around 2 foot  thick, constructed of sandstone bound with mud (clay, earth and chopped vegetation). On the outside they have been ribon pointed with cement mortar which will, eventually, be chased out and replaced with more appropriate lime mortar.

Internally from what we can see, they were pointed with lime mortar.  Although there’s not much evidence left on the inside as most disappeared along with the cement render we had to chip off. There is evidence that the inside of the cottage was lime washed directly on the stone although some had, at a later period been lime plastered.

We are planning to compact the mud as far as possible then repoint with lime. The majority of the stone walls will be left exposed, some will be limewashed and most of the brick walls will be  traditional lime plaster to enable the walls to breath, at least one way, until the cement render on the rear of the property is replaced with traditional lime render.

Earth / Mud mortar between sandstone

Mud / Earth Mortar in some parts flush with face of the stone

 A closer look showing how the mud /Earth would need to be raked out? or compacted back?

close up of Mud mortar

Close up showing some overpointing with lime plaster / mortar

So is compacting the mud back and repointing with lime the way to go? It’s the only option the I can come up with as there’s scant information around on this type of construction. Any comments or suggestions gratefully received down at bottom of this page.  In the mean time I’ll ask the question on the Period Property UK forum (where many “lime experts” can be found)

Just to put this wall in context, this is the kitchen wall after removing the OPC cement render:

Kitchen wall stripped of cement render

Mud mortar stone wall revealed in the kitchen


One Response to “What to do with Earth / Mud Mortar Walls?”

  1. By OPC (ordinary portland cement) do you mean NFCS (new fangled cementy stuff)?

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