That is, at every joint, leave a 2 to 3 mm gap to insert adequate gap filler.

He said anything less than this would just tear apart.

The WeatherTex was installed during winter and when we reached summer I was disappointed to see that every single joint had ripped.

I wasn't too fussed - I just put it down to me not allowing a large enough gap.

I merely resolved to rake out all these joints and have another go, once the wall was protected by the veranda structure.

I was even less worried about the first 6 rows closest to the ground.

My helper, on the day, had merely smeared some filler in using a spatula.

The boards, higher up, I had treated myself, pushing in substantial amounts of filler in to the gaps using a caulking gun.

Perhaps, the more disturbing observation was that at either end, the boards had retreated by 1 or 2 mm from the wooden end stops.

This was particularly disappointing as I had very carefully cut every board to bring it very flush to the end stops.

I hadn't really thought any more about this until this Monday morning when I was meeting a structural engineer out on site about another matter.

We came to be discussing the cladding of the house and he was particularly scathing, almost indignant, that the WeatherTex was moving. He said that the supplier of any building material should ensure that it was stable for shrinkage or expansion before it was delivered to the customer.

I know that I carefully kept all the WeatherTex under cover from the moment I took delivery,

I also know that, even though we installed it in the rain, the work area was kept dry with tarpaulins which were not removed until the cladding had been painted with good quality external paint.