A strange title in a way, but there is rationale behind it. To many of us, the older terrace housing is a home, something to be loved and cared for as it provides us with the shelter, location and amenities that we desire in our towns and cities. To others it is a vehicle for profit, a solid stone face to apply builders lipstick and foundation in order to sell on for a quick buck. Others see the character filled houses as purely a stepping stone up the property ladder, so there is risk that many of these old houses don’t get the thought and love that they deserve.
Whichever way you look at these terraces, however, they are all basically mini castles. These are houses that were built using traditional materials and techniques, most notably stone, rubble and lime mortar, just like the castles of old. But like all things there was a slight twist. The industrial nature of south Wales meant that not all the materials were local, some came from as far a field as Ireland and France. Stone was used as ballast in the coal ships on their return journey so no wonder you occasionally find that hit a bit of very hard granite when drilling in your walls to hang a shelf. The famous, and some might say, infamous, black mortar was due to lime mortar being made with ash from the local heavy industries. Bricks were made locally though, you only have to look at the side of Cathays Community Centre to see all the hands prints from long ago that were imprinted in the soft clay. But despite these slight quirks that fact remains that they are historical buildings that require traditional materials and skills to keep them working properly.
If we started covering our historic castles in Wales with modern hard and impervious cement renders, the Welsh public would be up in arms, yet we have, for decades done just this with our famous and distinctive terraces in south Wales. Old stone, brick and ornate lime renders have been lost to pebble-dash, cement renders, stone cladding and a lick of masonry paint. Don’t get me wrong I am not against progress and modern materials. Far from it, everything has its place, however these are just wrong to use on the older pre first world war buildings.
Having lived in a 1890’s terrace for 12 years I have witnessed first hand the troubles that conventional ‘renovation’ has had on the building. I have damp half way up my internal walls, random damp patches on the first floor and a cold house. Given that I have a central heating system, two wood stoves and a lovely wife you likes cooking, I should be sweltering. The basic issue is that the walls have been ‘damp-proofed’. I use quotes as there is no real way of damp proofing a house with solid walls using conventional pressure injection techniques – the fluid is just pressurised into all the voids in between the stone and rubble. The process also means hacking off the old lime render and replacing it with cement render, this seals up the wall and keeps the moisture locked in. This sounds OK, but the rising damp will always find a way and so capillary action draws the damp up the wall until it hits the ‘breathing’ lime. It then comes through the render and gives me my trade mark damp patches about a metre up the wall. Meanwhile the wall is sodden and this damages the fabric of the wall and also seriously reduces its insulating values. A wet wall is a cold wall.
The other higher damp is caused by cracks in the render letting rainwater into the structure. Once in it cannot escape back to the outside, so lo and behold it makes its meandering way through the wall to the inside. Water from rain and soil bring salts and these are concentrated in the damp areas and this makes my paint fall off of the walls.
Thankfully, the clay paint that I use for decorating shows up these damp areas and alerted me to them before the mould appeared.
So to solutions, first of all if you haven’t rendered your house with cement, please don’t. It will cause no end of problems later, either for you, or for the next occupant. The best answer to cure damp walls is to apply a lime putty render (with stone dust aggregate) to the outside. This will draw out the moisture and leave the stone, bricks and rubble dry and hence create a better insulated wall, think of your fuel bills and climate change. Use breathable lime plaster on the inside as well, finished off with some lovely VOC free and extremely matt clay paint (see www.earthbornpaints.co.uk).
If you have inherited a cement rendered house and wish to cure the damp problems, but without hacking off all of the render and starting again, then I would recommend Dry Zone silicon injection cream. This is a DIY solution that creates a damp proof layer in the mortar in between the stone and bricks over a couple of weeks. Any salt infested render and plaster will need to be removed, but this is a much easier job than replacing all of the cement render.
These old terraces therefore have suffered much at the hands of an ill-informed construction industry, but there are ways of making them better and preserving the character of south Wales for generations to come. As pressure mounts for better energy efficient housing and year on year reductions in carbon emissions, surely it is better to refurbish our existing stock to a high level in a way that is sympathetic to its origins, using low impact materials and a bit of care and attention to detail so that the old terraces become beacons of excellence. Our castles once more.