attachment of edge portions 42 on opposite sides of the corner in applications where especially high strength is desired to aid the persons installing coating 10 achieve the correct radius in an interior corner coving 50 is pre cast preferably from the same polyurethane 27 as is being used for coating 10 coving 50 is installed in the corner and may be glued into place with any appropriate adhesive 51 known to the trade to fill in the vertex segment of the dihedral angle and define a radius first layer 20 is sprayed over coving 50 coving 50 also prevents a void from forming between cloth 41 and first layer 20 casting coving 50 from the same polyurethane 27 as first layer 20 is preferred for good adhesion between coving 50 and first layer 20 materials with different thermal expansion properties tend to separate from each other when exposed to thermal cycles including diurnal or seasonal variation also it is generally preferred that first layer 20 and second layer 30 be of the same polyurethane 27 that way first layer 20 and second layer 30 will share the same hardness chemical nature and thermal expansion characteristics different elastomers can be used for first layer 20 and second layer 30 if the two elastomers are sufficiently compatible most of the above cited examples of preferred elastomers and textiles are flammable and some evolve toxic fumes when burned a composite of silicone elastomer and glass fiber is inherently fire resistant and.