Real slate walls


Ian Stock


The master's work! Slate walling on Laurie Wright's Cwmcoediog Railway

 

Using authentic materials is arguably the ultimate way of achieving realism – the colouring and texture will almost automatically be right, and they will weather or wear in the same way as the original. In the case of structures, using real stone is also, of course, very durable! It is worth checking the original, though, as not all materials scale down equally well, but slate most certainly does.

 

My first ventures into this were inspired by Laurie Wright’s work on his Cwmcoediog Railway, where slate has been used with amazing effect to create both pillar fencing and cut slate walls.

 

The techniques are not complicated, but they are quite hard work, especially if conducted at ground level. Slate can be relatively easily obtained as old roofing materials from a builder or salvage yard; I have one of each locally who are normally happy for me to cart away broken slates at no cost.

 

 

 

 

A retaining wall at Queen's Forest Road on my Lower Bryandale Railway

 

I cut the slate using a wet wheel tile cutter, the important thing being to ensure adequate breathing protection as dust is sometimes created even by the wet-wheel. This is a noisy, messy and unpleasant job – though the more recent use of a plastic machine with a water-recycle facility has cut down on both noise and spray. I try to cut large batches to minimise the times I have to do this job, but I still usually end up under-estimating how far a given batch will go. Pieces cut to other sizes can serve as flag stones, platform coping slabs and a host of other purposes.

 

I cut the slate into 3cm wide strips – it’s quite important to use a constant width as it assists with producing true wall faces when building. I then cut the strips into various random lengths ranging from about 1cm to about 8cm. The slate is then washed in a bucket to remove all the slurry before being spread out to dry.

 

 

 

 

Pont Bwchlydd on my LBR has piers build from slate round breeze-block cores. The sides of the central pier were first tapered with an old hand saw.

 

Unlike cutting, the actual wall-building can be quite therapeutic, though it is not fast! I initially used exterior grade filler for mortar, but this still goes white over time, so recent walls have used real mortar bought in a tub from a DIY shed. The technique is pretty much like real walling – start by clearing any loose detritus from the proposed site, and lay a bed of mortar. It is important to have quite a wet mix, so that the mortar adheres to the slate. I mix small quantities in an old paint-roller tray, and by far my preferred implement for application is an artist’s palette knife diamond-shaped – a diamond-shaped one is just like a miniature mortar trowel! Courses are just built up one by one, not forgetting to bond (overlap) the stones.

 

Another important issue is to try to keep courses reasonably level, and to reserve some suitable coping stones for the top, unless you are going to cap them with small slates, as in Laurie’s example. I think he uses a resin glue to stick these small chips in place, but I may be wrong!

 

Retaining wall built to hide the edge of the paving slab on which the trach is laid.

 

The final step is to use a large, soft paintbrush to remove loose mortar from the face of the wall once the mortar has almost dried. Then admire even small quantities of this approach add something really special to a scene.

 

Slate can also be used to create pillar fencing - here by Laurie Wright. The pieces can be dressed with an old file blade on the edge of a house brick, then just hammered into the ground. They are wired together using fine wire, such as that found inside the green binding reels used by gardeners.