Really good quality wood! I bought 10 8x4ft beds which I have made 5 beds out of (stacked 2 together) I joined them using some metal joining plates (£10 for 10 from Amazon). The height is perfect and, as I’ve said, the wood is great quality. The corner brackets work well too once they’re all in place and secure. You could use some wood to further support the rigidity, but there’s no need. I don’t normally write reviews but the service and quality of the product at this relatively low price was worth the couple of minutes. I will be ordering more shortly!