I made…a big hole and filled it in again

Posted on August 18, 2009


If you read this blog for beautiful images, mouthwatering food and contemporary furniture then you’ll just have to look away for a minute – sorry. For the rest of you, welcome to my world of drains, deep trenches and tanking. The absence of any creative posts from me for a while is due to this diversion into below ground operations, so the least I can do is share it with you lucky people.

Lets rewind a couple of months…one Friday evening after a particularly heavy rainfall we found a puddle in the utility room, growing from underneath the tumble dryer. I was hoping for a simple plumbing job, but deep down I knew this was something more serious. The rear of the house is a new extension, that was built into the slope some 10 years ago before we owned the place. I have the drawings for it and they show tanking membranes, but the builder thought he knew better or more to the point knew his clients did not. I had previously done some excavations here, so I knew the required membrane was missing altogether. Although the wall has always been damp it seemed surpisingly minimal, so it went on my list of things to worry about later. Needless to say, the puddle ensured that the job moved to the top of the list.

To remedy the problem I had to excavate down to below slab level by hand, about 1.5m, to gain access to the outside of the wall. After this the area was left to dry for several weeks, before cleaning down and flush pointing the voids.

I installed a new drain spur to pick up the rainwater pipe from the workshop roof, as this was previously discharging into the ground, right next to the untanked wall.

I then painted on 2 coats of bitumen primer and stuck on the Proofex membrane to complete the seal. This membrane is very sticky and getting this off the backing paper and onto the wall at the bottom of a deep trench, only as wide as my shoulders was no mean feat. Its for the best that there is no audio on this blog.

After the membrane was all on, the excavation was backfilled with gravel to ensure free draining of groundwater in the future. So with the rainwater pipe connected and the gravel in, it is complete.


So there you are; its not beautiful or creative, but I made it.


Posted in: Ed, House