A Quote for £3.5k on Potential Roof Repairs Triggers a Roof Verge Failure Inspection

 

Roof verge failure

Roof verge failure

We were recently called to a property in Stoke on Trent after a client was quoted £3.5k for substantial roof repairs. This is quite a chunk of money considering that the roof was on a property built in the mid 90’s; surely we can expect a new roof to last longer than 20 years can’t we?

What we found on attending was fairly representative of the issues we find when inspecting fairly modern roofing installations.

We found substantial failure of the cement verge fillets and resultant moisture damage to both the cement board undercloak and the tannelised roof batten ends. We understand that the roofer had suggested works to replace the sarking membrane but since water ingress by

wind driven rain or otherwise, had not been a problem then this was clearly an unnecessary recommendation. Wind driven rain tends to only affect shallow pitch roofing and since this roof pitch was circa 45 degrees then we saw no need to spend money addressing a problem that didn’t exist.

Defects

On inspecting the roof from a ladder we noted a number of key defects:

Cracking, failure and close of cement verge fillets
Wet rot to the roof batten ends
Damaged and missing cement board undercloak
Sarking membrane not draped into gutter and no alternative eaves flashing detail.
Failure of roof verges is incredibly common and often stems from two underlying problems:

The mortar does not contain the minimum 30% required sharp sand.
The verge tiles have not been bedded on the mortar in one operation. It is a mistake to try and point verges after the tiles are already in place and given the depth of remaining cement verge fillets, we feel that this is precisely what happened. Failed verge fillets are top of the NHBC’s hit list because it is one of their most commonly reported defects on relatively new build properties. They also commonly report a failure to add sharp sand to the roof mortar mix.

Read the full blog here…  http://buildingdefectanalysis.co.uk/roofing/verging-on-poor-build-standards/