Since 2004, Mr Inspector, a qualified building inspector has been carrying out building and pest inspections around Melbourne and most defects are caused by lack of maiontenace by home owners.
Although rarely respected by home owners, site maintenance is very necessary and should be closely adhered in order to minimize long term damage to a dwellings structure.
Home owners appear to exhibit more emphasis on the actual cosmetic appearance of their home and pay little regard to the maintenance of the site around the home.
There are websites (CSIRO, Victoria Building Commission) and the specific Australian Standards that publish information related to site maintenance but it is not pushed upon home owners.
Generally, today’s chain of construction starts at the ground or the soil. In other words, the footings are not designed for a home until an analysis of the sites soil structure is completed. Experts analyze the sites soil by various methods and then classify the soil type.
• A = Stable or non-reactive.
• S = slightly reactive.
• M = moderately reactive.
• H = highly reactive
• E = extremely reactive.
• Filled sites and “P” class sites are also included, but to be avoided.
Once the site is classed the engineers give expert advice on footing design methods to accommodate for any potential movement in the super structure.
One has to ask why all this soil testing and expense is necessary when in the early 1900’s (when soil testing was not conducted), many homes/buildings built in this era and before are still standing and the superstructure is relatively intact. I can only assume that buildings in this era were over engineered and expense was not a major consideration.
My experience in the building inspections Melbourne wide is that there is more movement cracking in homes built in the 1970’s to current day than in older dwellings constructed in the early 1900’s.
Earlier construction methods and materials combined with the dramatic climate changes and drought in Australia have seen a lot of differential movement in homes which is causing concern to home owners. Of course there are a number of other possible reasons for these problems other than the drought which range from poor workmanship, thermal movement, poor design to earth tremors. Due to ongoing problems with structures and cost rectification we have developed what is believed to be the appropriate construction design to minimize potential problems with structures.
I will attempt to identify strategies that a home owner can adopt to maintain the life of their homes.
Information published by the CSIRO and the Australian Standards AS 2970 emphasizes site maintenance.
I would emphasize that there are other strategies that one could adopt to maintain a homes’ structure, along with site maintenance. For example and not limited to;
- Regularly cleaning out gutters.
- Regularly cleaning external drains, open spoon drains and storm water pit drains.
- Capping down pipe bases to prevent debris blocking same.
- Updating storm water drainage to actually flow to storm water rather than under a home or near the base of the perimeter wall or slab.
- Inspecting and maintaining roof cladding.
- Increasing sub floor ventilation to comply with current requirements stipulated by the BCA.
- Regular plumbing inspections.
- Regular inspections for rot or timber decay and causes of same.
- Termite inspections.
- Removal or trimming of climbing plants.
- Treatment and painting of timber cladding, door and window architraves.
- Drainage should be monitored after a heavy rainfall.
- It is important that water does not lie against the base of walls; surrounding paths and ground levels should be sloped so as to drain water away from walls.
- Make sure that downpipes don’t disgorge storm water onto lower walls or plinths. Storm water should be carried well away by large, regularly cleaned drains.
- Ground levels may need to be lowered to expose a buried DPC. In cases where there is no DPC, lowering of ground levels may be needed to encourage drying of capillary moisture to occur at lower levels, thus limiting damage. This practice is extended in the technique known as air drains, a method for controlling damp by encouraging evaporation to occur at the lowest possible level.
Home maintenance is almost as equally important as site maintenance in my opinion. There are a number of procedures that one should adhere to in order to maintain the site around the home and thus reduce the amount of time, money and effort maintaining and repairing one’s home.
I will touch on these procedures individually.
The sub floor soil (dwellings on stumps) should be graded in order to not allow any water ponding.The soil around the perimeter of the dwellings walls should be graded or drained so that water does no pond near walls. For every 1 meter, there shou8ld be a 50 mm fall away from the walls.
Garden beds/retaining garden walls, planter boxes should not be constructed against the homes walls.
Plants should not be permitted to block vents or weep holes.
Plating of trees against the homes walls should be avoided. Trees should be restricted to a distance of 1 ½ times the mature height for class E sites, 1 times the mature height for class H sites and ¾ the mature height for class M sites.
Removal of large trees close to the dwelling walls can cause footings issues and a structural engineer should be consulted on the best methods.
In certain circumstances, root barriers can be inserted to prevent structural problems.
Excess moisture from leaks, over watering and poor grading of land can also potentially cause significant footings problems for some sites, in particular dwellings on slabs.
I would conclude that unfortunately a lot of the information that is available detailing methods to maintain ones site and home are rarely adhered to by home owners. This is done at their own peril and I believe more should be provided by perhaps councils or the REIV in order to properly educate home owners on methods of maintaining their assets and thus adding value rather than decreasing it.