Manhole Cover Frame Installation Do's and Don'ts Do's Frame placement Frame co-incident with edge of chamber opening Frame support Frame set back from edge of chamber but fully supported by chamber Additional support Oversize frame exceeding external limits of chamber top but fully supported by additional structure Bedding mortar thickness Thickness of bedding mortar between chamber and manhole cover frame is perfect Between 10-50mm bedding mortar thickness Bedding mortar encapsulation Encapsulate frame flange entirely for a robust bedding installation Corbelling Industry Standards and compliant structure correctly aligned Don'ts Frame placement Frame overhanging edge of chamber Frame support Frame set back from edge of chamber and not fully supported Additional support Cover support fouling on chamber top structure Bedding mortar thickness Thickness of bedding mortar between chamber and manhole cover frame too thin Less than 10mm bedding mortar thickness is not advised Bedding mortar encapsulation Absence of bedding mortar from top of frame flange Corbelling Corbelling non-compliant to industry Standards and CoP