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Building and Pest Inspections During Wet Weather

One of the most commonly asked questions during periods of rain is it a good time to do a building inspection and pest inspection. I believe it is the best time as you can identify any leaks, wet areas, the overland flow of water. And if the water flows away quickly from the house and generally de-waters the property. You are also able to see if guttering and downpipes are sufficient for your needs if there is any backup water pipes or blocked pipes.

During the last few weeks, Brisbane and its surrounding suburbs have been inundated with large volumes of rain. This inclement weather has impacted beneficially on our ability to do quality building inspections. The rain has made any opportunity for a leak occur in an element of a building whether it be the roof the windows exterior walls gutters and downpipes there has been sufficient wet weather to enable these leaks to present.

Even in my own home, a leak presented where an extension abutted up to the old dwelling. On investigation I found that the weathering and scribing on the metal sheeting (though an excellent job was done) still enabled water to be pushed back in and into the house proper.

I was able to determine that when the new roof was installed the tradespeople had used a small amount of silicon over screw holes and around the scribing. Over time with the effects of weathering, heat shrinking and expanding this silicon now allowed water entry.


What I did was use Silver Tack to seal the holes and make a semi-permanent repair. Semi-permanent I expect to get 8 to 10 years without any problem.

During building inspections in times of wet weather, it is very hazardous to climb on top of a roof and would most certainly contravene health and safety regulations. We can climb inside the roof void during this time, and you can see any water ingress, that may take the advantage of gaining access through holes and metal roofing or cracked in tile roofing.


Cracked roof tile located during a building inspection

By using a thermal camera inside though we do not have access to the roof covering because of health and safety issues, we are easily able to determine water leaks even in skillion or cathedral roof areas where there usually is no access at all. The variation in temperature caused by water is readily discovered by using a thermal camera.


Water leaks visible with thermal during a building inspection

During a building Inspection and pest inspection it is the ideal time to do the examination of the gutters and downpipes and general yard drainage. During periods of wet weather, the gutters will show any leaks quite readily. If they are prone to blockage by leaves, we will see overflowing gutters and downpipes that have water backing up into the gutters or even water bubbling out of the base of the downpipes where they have been broken or blocked. It is part of a building inspection and pest inspection to try to determine if the flow of water around the house ensures that no water is directed to external walls or underneath the house. When you inspect the home during periods of dry weather you are not fully able to determine that water is directed away from the house and water is not gaining entry via weep holes or pooling of ponding on the outside of the building. During dry weather building inspector and pest inspector can only look for tell-tale signs of water against the house staining, moss growing or soft and sunken soil areas but during wet weather we can see exactly what’s happening with the drainage.


Water overflowing From blocked downpipes during a building inspection

Water escaping gutters during a building inspection

During the extended period of dry weather and subsequent water shortages and restrictions in Brisbane In the early 2000’s a lot of homes put in water tanks to capture access rainwater. We can see the impact of these rainwater tanks their overflows during periods of wet weather, and if there is the possibility, they will impact negatively on the structure by directing water against the side of the building increasing the moisture in the soil near the building. And sometimes it is just as simple as seeing if the plumbing is adequate around water tanks.

In homes where there are subfloors when doing a building inspection and pest inspection, we can determine if there is water ingress under the house or if there is drainage issues where water moves through the soil or in worst-case scenarios the overland flow of water directly underneath all these items will impact on the long-term use of a house. Normally we can only see the results of water flowing under the house may be some erosion discolouration of soil or a damp, musty smell but during rain periods we can easily recognise if drainage is an issue.


Water escaping gutters during a building inspection

It is a regular occurrence when we were doing building inspection and pest inspections for Twinspectors to use thermal image camera, which can readily show up any moisture leaks from ceiling areas in and around windows.

Sometimes the design of the house has an impact on how waterproof a home may be, and at your building inspection and pest inspection the inspector will be looking at the exterior cladding, commenting on window flashings if not visible, door flashings if required investigating the waterproofing methods of the exterior sheeting. in modern homes, the eve is not giving protection to the external walls. Modern homes also use large sheets by the Blue Board or Hardyflex as the exterior cladding the joins in these areas need to be well sealed, and sometimes timber is used as a decorative cover these timbers will decay over time allowed water entry. Again the use of thermal cameras and moisture metres during building inspections will readily discover these leaks during a thorough building inspection  and pest inspection.

During a building inspection downpipe leaks could readily be seen, with water flowing down the outside increasing the moisture on the outside walls. Windows and doors showed signs of water penetration around flashings, especially in areas where there was no eves present.

When you are doing Building inspections internally during wet weather, you can confirm a multitude of possible wet areas. For example, there may be a water stain to the roof void on the gyprock during periods of dry weather we can report on the stain. Still, we are unable to accurately determine if the possible or previous water leak has been repaired. During periods of rain if it is leaking the thermal cameras will quickly determine if moisture is present.

Seals around doors and windows or incorrectly fitted flashings will become very evident during wet weather and easily identified. Whereat other times no evidence may present all we may rely on tell-tale signs when determining if a leak has previously occurred. These are things like water staining evidence of drip line down the walls evidence of mould or again that musty smell.

Building and pest inspections are best done during inclement weather

One of the main difficulties with doing Buildings inspection during periods of sustained fair or good weather is that you are unable to determine whether water stains watermarks decay or other evidence of water ingress is current or has it been repaired. A watermark on timber will remain there forever and the water may have occurred during construction or it may have occurred during the last period of heavy weather.

Sometimes repairs are evident; tiles have been replaced or resealed roof tiles have been recoated. There may be evidence of repairs by the installation of silicon, black tar or other waterproofing compounds.

Heavy rain aids in identifying whether water is directed against the side or underneath a dwelling. It is very important that water doesn’t run under or around structures; this will soften the soil and allow for unintended movement in the footings or foundations which will cause doors to jam windows to stick possibly even cracking on brickwork or gyprock.

Internally when doing a building inspection and pest inspection during periods of wet weather, it is not uncommon to find elevated moisture under Windows or along skirting boards of external walls. This elevated moisture is generally because of poor or inadequate flashing around the windows and inside the walls on a lot of occasions is because water has been allowed to enter via weep holes. Neither of these would be visible during dry periods.

I am an owner of a Building Inspection and Pest Inspection Business and I would advise any prospective purchaser to have their building inspection and pest inspection undertaken during the worst possible weather because one of the things I’ve found in all the time of been doing this job is that 99% of all problems occur for 2 reasons one too much water around the house or to little.

In this article I have concentrated on the building side of the building inspection and pest inspection but there is also the pest side, and during periods of extended wet weather in high humidity termites become very active, and the soft damp soil makes their foraging a lot easier. Hence evidence of termites in dry weather can readily turn to active termites in rainy weather, and these can easily be found.