Help!

[Jacob]

I'm definitely NOT into "proper woodworking" so cannot speak from experience, but member @custard definitely IS - he's one of several professional wood workers resident as members here.

I strongly recommend that you read his sticky on edge joining boards. Here's the link (it's at the top of this section):

How To Edge Joint | UKworkshop.co.uk

Good luck & HTH

If you join them really well they may still split but not necessarily along the glue line, unless you make provision for movement i.e. attach with buttons or similar.

 

[thetyreman]

If you make something similar again, use tongue and groove or shiplap boards to allow it to move without creating gaps (don't glue them together)

I would also only use turnbuttons so the entire top can float and freely move as jacob says, nobody will see it as it would be all hidden underneath the top anyway.

 

[Stanleymonkey]

Did you buy the gravel boards from a supplier or did you have them at home?

Suppliers will often store that stuff outside or partially under cover. Probably a lot wetter than you realise. I picked up some 3metre arris rail yesterday. Was up on the high racking outdoors and had to be forklifted down - pallet was soaked as it had just chucked it down.

 

[RusticClay]

Yes I bought them from a supplier. They didn’t seem unduly wet and I let them acclimatise outside for a couple of days too