Eyebrows are often raised when I tell people they have 'rubble-filled' walls.  They seem to think that I'm either denigrating their property, or else they sense a hidden reference to the 'Flinstones'.  Well, actually, no.  Not only do they exist, they're very common, and to illustrate the point, here's a photograph of one someone actually knocked down for me so I could put a picture on the website (actually, I made that last bit up).

A Rubble-Filled Stone Wall

When you see a lovely, old stone wall, it's easy to think that it's constructed from even, regular stones, which slot together like a brick wall.  Nothing could be further from the truth.

Probably the only 'faced' portion of each individual stone is that which looks outwards; and those on the inside of the walls, which are probably meant to be plastered, aren't as 'fair faced' as those on the external leaf, which face towards the unwashed masses.

The depth of individual stones, from front to back, also varies.  Some of them even span the entire width of the wall, and these are known as 'through' stones.  Their purpose is to tie the inner and outer leaves together, so that stability is provided for the overall structure.

As the walls were being built, all the bits that were knocked off the individual stones were just dumped between the inner and outer face: hence the name.  Over the years, dirt and dust gets blown into the wall too, where it simply takes up residence.

In areas of extreme weather, such as on the top of Saddleworth Moor for example, where I was brought up by a flock of sheep, the stones were laid slightly out of level: higher at the back side than the front.  This was so that any rainwater, driven into the wall by ever constant 'Billy Wind' rolled out again.  At least that was the theory.

Less exposed areas relied on lime mortart to glue them together; and they weren't pointed in the absurd way they are today.  The joints would have simply been raked out so they were slightly less proud than the stone faces. I don't think this 'strap' type of pointing (shown below) gained popularity until well after the advent of sand and cement pointing.

Modern (and inappropriate) 'Strap' pointing on stone wall

Another poopular misconception is that rubble-filled walls have good insulating qualities: they don't.  They do have a long thermal lag though. So that once the wall is cold, it stays that way a long time.  The opposite applies too, if you can warm them up, they'll stay warm.  However, that represents a large portion of the family budget, spent on the gas bill to achieve.

Thus, if you have one of these walls facing towards the north, or perhaps it's shaded by the neighbour's leylandii, the best way to ensure it doesn't attract serious condensation is to insulate it from the inside.  Email me for details.

Just one more thing: how anyone can claim that his injection damp proofing system will provde an effective barrier to rising dampness in walls such as these is one brick short of a full load in my opinion.