Top of the list for defects - Parapets

Of all the different house styles and designs we've seen over 25 years of Surveying, the number one in our list, that results in defects that we are asked to look at, is the Parapet Wall. And for the last 10 years, Parapets really do seem to have been growing in fashion.

To start off, let's answer : What is a parapet or parapet wall?

A 'parapet' is the part of a wall that projects above the roof line. Sometimes formed around the lower edge of a roof, sometimes over a party wall, with others featuring along the gable-end edge.

Here we show a 'gable-end parapet wall' to a house, capped with concrete 'coping slabs':

The defects that we regularly see involving parapets mostly allow water ingress and cause internal dampness. The parapet walls are either not designed correctly, missing the necessary damp proof courses or cavity trays; or more often, the builder cut corners and used 'slap-dash' workmanship with no care of the consequences.

For the property in the photo above, the defects were also a rather more significant risk to life : really worryingly, each run of parapet (of about 9 slabs), relied upon just two screws to hold them up there. Not two screws per slab, oh no, two screws in total.

Here they are ringed in orange. This view is taken from above using our 10 metre long extending camera pole. (We were very tempted to draw a non-smilie face under!)

So what happens sometime later? Well, over the course of 4 years the screws rusted (that's right, they were not even adequately galvanised or stainless steel) and then they sheared-off and the slabs came tumbling down. We found this out when we were instructed to visit and assess what was going on!

At over 25kg each, and falling from 2nd storey height, just one slab would have caused significant risk of injury or death to anyone beneath at the time. By luck, and thankfully, no one and no other property was damaged on this occasion.

We've now specified for the client the correct installation and fixing details, that their designer and builder should have used originally.

Do you need to find out what's wrong with your parapet wall construction? Contact us now to obtain your fee quote.