Is it possible that our metal gate could be expanding in the hot summer weather? It has been well over 100 degrees daily on average for a month or so, and for some reason a metal gate we have had for years is not closing properly because it's just too big for it's gateway.

1 Answer 1


It is possible and should be relatively easy to estimate how much it is expanding based on the coefficient of thermal expansion, the size of the gate and how hot the gate gets.

One other issue you might to look at is movement of any posts supporting the gate. If you have had unusually dry weather for instance this may have caused the ground supporting any posts to move and that could cause a similar problem.

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    yea i agree- but mostly with the actual posts moving. In South Africa we also got about 104f and I dealt with metal structures and gates and the expansion/contraction was not that bad. Are you talking about several inches/cm?
    – Piotr Kula
    Jul 19, 2011 at 9:38
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    @ppumkin, that is a fair point although issues such as the amount of shade, the material for the gate, the surface colour of the gate, the temperature when the gate was installed etc. can all have an effect so what happens to one won't necesserily happen to another. The amount of thermal movement would however be expected to be small, measured in mm rather than cm.
    – Ian Turner
    Jul 19, 2011 at 10:25
  • yea im talking about mm - black was a very popular colour for gates- and the longest ones I installed was a pair of 4.5metres long and 2.4m High that made an isolation cage between the farm and public road. :D on a private game lodge in the centre of the scorching bush.. no problem till today :)
    – Piotr Kula
    Jul 19, 2011 at 13:50
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    This gate is 36" wide. I just measured both the top and the bottom, and both are 36" exactly. I also measured the top and bottom of the gateway between the posts, and it is an inch more narrow at the top than the bottom, so I suspect it is indeed movement of the posts. That's disappointing because that seems a lot more difficult to get repaired.
    – btt
    Jul 19, 2011 at 14:11
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    Yea- your posts subsided most problably because of the severe hot conditions and caused the sand to 'shrink' - usually means that the ground before foundation was not compacted properly.. You might have to take down the affected post and redo it- make sure to properly compact the ground under it with materials that struggle to adsorb water- eg old rubble,stones, etc. water it- wait 1 or 2 days (in hot conditions) let dry then rebuild the post...
    – Piotr Kula
    Jul 19, 2011 at 15:32

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