Composite expansion gaps

[robbieee]

Hi all

I installed a 9m x 6m composite decking in my garden. When I installed 18 months ago the expansion gaps were 3mm and perfect. Now they are all uneven (see pic). What should i do to fix this to ensure it doesn't happen again?

Any help would be appreciated!

 

[foxhole]

What are they fixed to?

 

[robbieee]

What are they fixed to?

Timber frame and hidden plastic fixings every 300mm:

 

[foxhole]

Your timber frame has most of the movement , composite has very little expansion.

 

[robbieee]

Your timber frame has most of the movement , composite has very little expansion.

The boards are all expanding at different gaps so I'm not sure its the timber

 

[freddiemercurystwin]

Are all the boards the same length?

 

[robbieee]

Are all the boards the same length?

Yep all 3.6m

 

[foxhole]

The boards are all expanding at different gaps so I'm not sure its the timber

Those fixing look like they only hold via friction,? ,would imagine they are not very effective with smooth material like composite boards.Are the external ends of the boards restricted from movement( framed)?