Masonry Glazing

 

The stained glass panels are sealed in the stone channel with traditional lime putty mortar.  Its unique qualities are its softness, malleabilty and ability to self repair any minor cracking that may occur. It is the only material suitable for setting stained glass into stone and custodians need to be wary that portland cement mortars, linseed oil putty or waterproof mastics are never used for this purpose as they could lead to breakage of the glass, splitting of the lead structure and damage to the stonework.

 

Most church windows are set directly into a channel in the stone or masonry frame exactly as they were in the middle ages.  This has proven to be a most successful glazing system for both longevity and support of stained glass, as long as the original materials and methods are adhered to.

A masonry glazed window is made up of two or more stained glass panels of manageable size.  The panels are stacked one on top of another, in the glazing channel, and fit together with a special waterproof joining seam to make up a complete window.

The use of lime putty mortar dates back to ancient times but its preparation is a skill that has been progressively lost to the building trades since the introduction of portland cement in the late nineteenth century.  Lime putty needs to be prepared at least 3 months in advance of its use in order for it to mature but unfortunately most builders and bricklayers no longer have experience of its preparation and use.

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