A Mighty Strong Mix

I was on site this afternoon and was immediately struck by the speed with which the scaffolding is going up: it's almost breathtaking.  On two sides no less than four levels of walkway are now in place, so from the top one....

....one can now peer in at the level of the battlements' footwalk.  That progress has been so rapid is fortunate as tomorrow sees a visit from officials from Historic Scotland, who will be at the castle to review progress.  They will also discuss with the project's architect, Francis Shaw of Wighton Jagger Shaw Architects, project engineer Brian Smith, and archaeologist Tom Addyman, the extent of the repairs that will be needed, the repairs schedule, and Brian's scheme for reinforcement of the structure.  As Francis put it, it will be a day of negotiating, during which everyone will be working towards what is best for this wonderful castle.

And getting up close makes even someone as ignorant as I realise just how special this building is.  The quality of stonemasonry is remarkable - just look how straight and true this wall is, and....

 ....how neatly this corner has been formed.

But what is perhaps most remarkable is the mortar that holds the whole structure upright.  As builder John-Paul Ashley of Ashley Thompson put it, on most of the jobs he's done involving historic buildings, he could scoop out the mortar with a finger.  Try that on Mingary and all you get is a sore finger.  The mortar is 700 years old and still absolutely solid.

The secret, so John-Paul says, is in the 'ingredients', which are part lime, part shell sand, and part a gravel of whinstone - that's the igneous rock dolerite - which react together to give the mix its strength.  The remarkable condition of the mortar means that much less rebuilding has to happen - which is good news for tomorrow's discussions with Historic Scotland.

Few people appreciate that the castle was originally harled - that is, it had a covering of mortar mix, as seen here.  The result was that the rocks of which the walls were built were completely hidden.  One of the decisions that has to be made is whether to replace the harl - as was done, controversially, at Stirling Castle - or whether to leave the stone walls bare.