• Campbell Sutherland

A common issue, in residential homes, which is often overlooked - Ground Clearance.

Updated: Jun 12, 2019

The 1st (out of 5) common scenarios, I am currently finding when writing up my building reports for clients in the Wellington area, often overlooked, and unseen is insufficient ground clearance.

Without dictating the building code, and trying to simplify the term, basically it's the distance between the finished ground level and the bottom of the cladding.

This can also include the distance between the ground, and foundation structural timbers.

In Wellington, most homes are built on contoured ground, meaning one side of the home maybe set quite high off the ground, where the rear of the home maybe set very close to the ground level, because it sits aside a hill. I'm finding in many of these situations, the cladding and foundation are in very close proximity, and unfortunately have surface water ingress, and significant deterioration to structural timbers. This is just one scenario of many. Another example is, the home has been built too close to the ground, with very little thought for ground clearances.

To contribute to that, landscaping has been added throughout the years, concrete / paving / gardens etc to bring the ground level up even higher. This example is resulting in deterioration, not just to the cladding, but to the main building elements which aren't on show, the structural framing (bottom plate & studs) and in some cases the foundation structural timbers.

The first example in the group of pictures below, is a good traditional weatherboard home. The cladding is in excellent condition, however the home is built on a hill. The rear of the home, cladding and foundations, are in close proximity to the paved surface. The concrete may have been poured at a later date, to the homes construction date. There should be a minimum ground clearance of 150 mm, in simplified terms. Unknown to the home owner, surface water has pooled in this area and significant deterioration can be seen to the timber bearer. I also had to recommend further investigation to the structural timbers behind the gib walls and cladding, as the moisture meter, was reading high levels of moisture within the structural framing timbers.

The second example in the group of pictures below, I commonly, and unfortunately see all the time, is an early 90's home which was built with very little, to no ground clearance, between the inside floor level / the cladding threshold, and paved surface outside. The only measure saving this home from flooding in a heavy downpour, was the fact surface water run off could flow down a hill, to a neighboring property and away from this home. Ground contour is also a consideration of mine when inspecting a home, which I will elaborate on in another blog. No consideration was given to the ground clearance when paving this home, these situations are almost inevitably pre-determined.

Next to the gully trap in the photo, there is a break in the cladding. I could put my hand in there, and apart from relocating a weta, I found the structural bottom plate and studs, to have been in the consistency of weetbix. Surface water was pooling in this area, the studs behind were soaking up the moisture and deteriorating, every time there was a heavy rain deluge. I actually found high moisture levels throughout the length of the wall, The builder that was recommended to further investigate, told me, he had found extensive deterioration to the structural studs.

Apart from the expense of remedial repairs, there are various techniques that can be implemented to help alleviate the problem of the lack of ground clearance. Every scenario is different and when using Total home Inspection Services, for your home inspection, I can advise on the numerous options, that can be undertaken, to minimize the potential risk.

42 views0 comments