Things to consider before you commission any stonework (Or how to tell a stonemason from the rest)

Are they a stonemason?

A simple question. After all, anyone can get business cards printed or paint it on the side of their van. But a stonemason is an ancient trade or craft and while it can take only 2 years to qualify, it takes a lifetime to master. It incorporates carving, sculpture, letter-carving, rubble-walling, fixing or building with the stone, and multiple other disciplines.

Do they have a track-record in working with natural stone?

I qualified in 1995 and have worked ever since in the stone trade. Knowing how to handle the stone (which is surprisingly fragile) and even how to carry it on your own or with another person is of paramount importance. After all, it may take weeks to work a single stone for a cathedral, and only a few seconds to ruin it with clumsiness or bad/rough handling.

Will they be matching the original stone?

I recently went to a distinguished building where I had contributed new coping stones to the various gables. I had, however, lost the next pitch to another company who I won’t name. When I revisited the site they had replaced a single Bath stone mullion with a brand new Portland one. Both limestones, yet utterly different in colour and texture. Absolutely shocking. The company involved should be ashamed of themselves.

A Portland stone mullion in a Bath stone window surround.

Do they know what the stone on your house is?

I’ll bet you I do. And if you live in London and the builder mason says your house is made of sandstone, then you can take it from me that in 99% of cases he’s full of sxxt.

Do they know the difference between limestone and sandstone?

Again, a lot of prestigious buildings such as St Pancras Hotel comprise on the exterior of sandstone, limestone, brick and terracotta. It’s not particularly advisable to mix the 2 as the lime from the limestone can adversely affect the sandstone. It’s very unusual for a London house to contain sandstone in its fabric, the majority of which use Bath stone for their decorative features.

Do they use lime mortar or cement?

When I first started we used sand and cement mortar and add hydrated lime to prevent the mortar from drying really stiff and damaging the stone. This was a practice left over from the Victorian era. Nowadays there has been a volte face and all masons use lime and sand in their mortar, whether its hydraulic lime, lime putty, hot lime or other techniques.

Do they bond their stonework in 3mm or 12mm joints?

Bricklayers work on the standard 12mm joints. Precast stone (or concrete as Masons dismissingly refer to it) is manufactured for bricklayers to assemble with 12 mm joints. As a result, we masons can spot it a mile off. Masons work to much smaller joints – 2-4mm. We colour match the mortar too so as to make the joints disappear.

 

Just a few points in my occasional blog. There are no doubt lots more. Please drop me a line with questions or amendments. Thanks.

What do you think?



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