Keeping the Rain Out

It rains here, a lot.  Today's fine morning will become this afternoon's near gale and semi-horizontal rain.  Keeping all this water out of the castle is one of builders Ashley-Thompson's current headaches.

While most of the tops of the battlements are now capped, water is still getting in along the walkways.  This should be stopped shortly when the Rosendale flags which are on order arrive.  These flagstones are similar to the York stone used for the battlements' capping, but darker and more difficult to source as supplies are reclaimed stone from the floors of old mill buildings in Yorkshire and Lancashire.

In some places, such as along the courtyard wall of the north range, a more modern method of sealing the top of the wall has been used, though this, again, will be covered with Rosendale flagstones.

But the main problem is that water is driven into the faces of the walls through the gaps between the stones.  Although these are filled with extremely hard lime mortar, it's permeable, so the water is almost sucked in.  This problem is general in older, stone-built houses in this area of Scotland, with most houses solving it by having an outer 'harling', slaked lime and coarse aggregate mortar - follow link here for more information.  We know the castle used to have a harling skin - bits of it remain on some of the exterior stone.

At some point this harling was removed or left to fall away.  Long-term readers of this blog will know that, early on, re-harling the castle was actively considered.

But the builders now have a big ally on their side: the biomass wood chip boiler which was fired up on Saturday.  It's housed in a building set into the east end of the moat, so it will be out of sight.  The machinery consists of a boiler, the yellow and green machine, which is fed by....

....an electrically driven screw which transfers wood chippings from Ardnamurchan Estate's forestry from the hopper behind the breeze-blocks to the left.

 The red cylinder is a pump which forces the hot water from the grey storage cylinder....

....into the ground-floor room at the east end of the main range, where it's piped to....

....a control board.  The north range building has been sealed as much as possible, and is already nice and warm.  Although the heating is still on a low setting it's being slowly turned up.  The difference in the walls is already noticeable: they're drying out nicely.