Before I get sprung – I have to confess – the title was borrowed from a recent article about leaking high rise buildings in Hong Kong. The article makes the point that the problem of leaking buildings in modern construction is not limited to Australia.
I have spent 20 years in Melbourne working on buildings. Much of that time constructing new homes and apartments, as well as extending old inner city homes. In the last five years I have visited hundreds of homes and apartments – mainly in the inner city – carrying out leak investigations and finding ways to stop water getting into buildings.
One thing stands out as being a specifically modern problem is that new buildings leak? This problem is so widespread that it warrants a look at the types of leaks that occur and the reasons why.
Remember back to the “olden days” when dinosaurs roamed the earth and buildings were constructed from timber or brick and had such things as a tiled or steel roof with a steep roof pitch and substantial eaves. The designs and methods of construction were such that any water landing on the building would quickly flow off the roof or walls into a storm-water drain. Therefore – no water problem! Any leaks that did occur were related to the installation of one specific product by one specific trade – such as roof tiles, or roof sheeting.
Fast forward to the current situation. Homes, commercial buildings and apartment blocks are now routinely built with:
• Tiled balconies – located directly over living areas.
• Low angle steel roofing – with water running into box gutters sited behind parapet walls.
• Box gutters which run through the centre of buildings trying to remove the stormwater from a large area, low angle roof.
• Basement carparks which have persistent leakage from the time they are constructed.
• Interior floors which are 100mm below the level of the tiled balcony immediately outside the window or door.
• Tilt up concrete panel buildings that have continual damp plaster and water leaking between the panels.
• No eaves, which allows the designer to achieve the modern design aesthetic or to allow the building to be located on the site boundary.
These design features have a number of inbuilt problems.
• No eaves mean that walls, windows, doors are fully exposed to rainstorms and are more likely to leak where they fit into the building.
• Balconies are completely dependent on waterproof membranes to prevent water flowing into the building.
• Box gutters with minimal fall and frequently too small, are very vulnerable to blockage and overflow.
• Balconies fitted with drains are frequently poorly graded so that water drains to one point and the drain is located elsewhere. Pooling water will almost always find its way into the building.
• Basements with inadequate water control drains are very difficult to correct once the building is completed.
These defects in the building construction arise from several sources:
• The designer of the building never detailed the correct method for proper water sealing. The expectation is that the building contractor will have adequate knowledge or ability to ensure that the building is watertight.
• The building contractors frequently do not have adequate knowledge or experience to produce a watertight building.
• The contractors carrying out the work may be in a hurry or not be instructed properly to carry out the work. It takes the work of several different trades to install a tiled balcony for example. There is generally little coordination to carry out this critical and detailed work and in fact the different trades may never meet each other.
• The Building Surveyor may not have picked up such features as the exterior floor levels being higher than the interior floor, or various other non-compliant construction work.
As a result, many buildings leak due to this combination of factors.
So, what do you do if you have purchased a leaking building or apartment? Water is leaking though from the balcony above your living room, there is stained and rotting timber around the window frames, there is mould on the walls that you are cleaning off on a monthly basis, and the ceiling is in danger of collapse.
This is covered in the next exciting episode!