A very common fault we see in buildings are the door thresholds being too low or non-

existent (flush).

This door frame was sitting down on the tiled surface and water had been ingressing in for a very long-time causing destruction of structural timbers below and adjacent to the door frame.

In this case the screed, which was necessary to create the falls, but lifted the threshold point to zero. Bad planning right for the day it was built.


I presume the height of threshold was builder carried out “seen” by Building Surveyor before screeds were installed. Otherwise they would not (should not) have passed an inspection.


The outcome here was to remove the door frames (three in this job) – install a bottom plate and cement sheet upstand and detail that before the membrane was applied. This is the only way of ensuring a water-tight upturn below the door sill. Admittedly, being builders as well as waterproofers this task was more straightforward.


Yes, it more costly and sometimes a pain to do and the client has found more money to carry out the rectifications – but it has to be done.

Another building design fault (which the builder carried out !!)

is the cladding the door frame reveals was a very poor detail as there no ventilation gap behind cladding and no room to insert cement sheet upturn, so other door upstands were created by using zincalume flashing embedded into fresh membrane to prevent the flashing

rusting out in the future and then detailed on the front side.


Now awaiting new (shorter) door frames to be installed (no extra head height to lift existing door frames) The message here is don’t waterproof a job with low thresholds, you are just asking for a call back.



Paul Evans