Or, where further investigation of a material was required, such as a mortar analysis, prior to a decision being made on an appropriate material to use in the rendering of a building.
Neu, os oedd angen ymchwilio ymhellach i ddeunydd, megis dadansoddiad morter, cyn i benderfyniad gael ei wneud ynghylch deunydd priodol i'w ddefnyddio wrth rendro adeilad.