Greenhouse question

[garbax]

I noticed my parents greenhouse has 4 horizontal bars situated across the apex of their greenhouse, which I assume is for strengthening the roof. My greenhouse does not have these, possibly because its newer. Does anyone know their proper name and if I could buy them separately?

Thanks

[Kleftiwallah]

I have two greenhouses 'fused' together end to end so just for strength I have installed a cable secored by threaded staple bolts (similar to exhaust clamps on vehicles) and adjusted with a turnbuckle.

I would call solid bars doing the same job 'Bracing' bars, but don't forget when there is snow laying on the roof the weight will tend to push the apex down and the walls outwards.

Cheers, Tony.