Double garage water ingress

It isn’t only houses that suffer with damp and ground water seepage.  Our surveying team were called out to investigate why this double garage in Doncaster, South Yorkshire was constantly wet.  Water constantly ran out from the hillside, seeping into the garage and making it unusable.  Britannia Preservation was engaged to design and install a solution.

There are a few issues which make working with damp garages a little problematic:
1)    The level of the floor can rarely be altered, and
2)    The width of the garage cannot be significantly reduced, as this wastes valuable parking space.

Our surveying team quickly found that a combination of inadequate waterproofing installed during construction and a high water table resulted in permanent water seepage making the garage unusable.  The raft construction of the floor slab meant it would not be possible to install drainage in the floor.  Furthermore, the floor could not be replaced or raised in height.  The garage was, however, quite wide, and would not be adversely affected by a small loss of this width.  This meant that Aquachannel drainage could be placed on top of the floor directly in front of the external walls to create drainage solutions.  

The inner garage walls were treated with sealant and waterproofing membrane.  As the garage floor was higher than the road, this meant that the discharge from the Aquachannel outlets could be fed into the surface water drains by gravity, completely avoiding the added costs of a sump and water pump.  The installed system effectively manages the water that seeps in through the walls of the garage and, in practical terms, the garage is now dry and usable!  The design method meant the significant cost and disruption that would have been required to rebuild the garage was avoided.

This detached garage is built into a hillside.  The water that is visible on the road is a result of ground water seepage.

The walls and floor of the garage were permanently damp and, to all intents and purposes, the garage was unusable.

Damp ingress had resulted in build up of lime deposits.  Lime is present in hard water and is leached out of new concrete when water runs over the surface.  For this reason, the concrete surfaces within the trough were sealed with a lime inhibitor before the Aquachannels were installed.

This photograph shoes the extent of the dampness.  Water is visible in the right-hand rear corner of the garage and had formed a shallow pool.

The inside faces of the perimeter blockwork walls were lined with cavity drain membrane. Aquachannels were placed at the edge of the floor and a timber shutter erected in preparation for the formation of the concrete upstand.

This close up view illustrates how the upstand flange of the Aquachannels has been sealed to the cavity drain membrane.  The white pipe extending from the tip of the Aquachannel is a jetting eye that allows the channel to be flushed out with clean water during servicing intervals. The timbers form the shuttering for the concrete upstand.

This view shows the cavity drain membrane, Aquachannels, jetting eyes, and the timber shuttering ready to form the concrete upstand.  The concrete floor is already considerably drier than it was at the start of the project.

This is the extreme front end of one of the Aquachannels protruding through the front wall of the garage. This is a temporary outlet and drainage channels, connected into the surface water drains, were later installed at each side of the driveway.

The surfaces of the concrete were treated with a water resistant sealant and covered with a new skin of blockwork.  The white jetting eye seen protruding from the concrete toward the rear of the image provides easy access to flush out the system.  As you can see, the floor is now completely dry and shows just how effective this method has been in controlling ingress of water through the garage walls.

 If you’ve been flooded; have a basement, cellar or other below-ground area that you wish to transform into dry, useable accommodation; or want to know more about our services, please contact us.