Decking Northern Ireland | ... cost-effective and practical solution for all your decking supplies. Components include deck sub frames and legs, joists, decking boards, deck posts, base rails, hand rails, spindles. The diagram below should help you to decide what you need. Decking components. Our HALDECK outdoor timber components are treated with Tanalith E wood preservative, providing complete protection against decaying and fungus meaning your deck will keep its beautiful appearance for longer.