Replacing decking boards with different thickness

[Mountaindreamer]

Hi, I'm in the middle of a project to repair my cedar decking. The sub-structure has deteriorated and most needs replacing, and some of the cedar is significantly worn at the edges. I'm trying to re-use as much as the cedar as possible, turning over and cleaning the underside will give it a new look. However, some has to be replaced with a different timber, as the cedar boards are prohibitively expensive and I haven't found a stockist that can provide the same thickness boards. Hence I'm left with a reasonable option to include some Siberian larch, only its 8mm thinner. To retain the same level as the existing boards, i think the best option, which avoids re-building part of the decking sub-strucuture, is to use some sort of spacer/shim of 8mm on the joints where the new boards will be laid. I'd appreciate some ideas on what that might be, I haven't found treated timber 8mm thick, and even if I did, I imagine it wouldn't particularly durable.

 

[big all]

you could probably use t&g matchboard [V groove cladding ]it comes out about 7.5mm it would need treating and probably ripped down the middle to give 2x40mm strips

 

[Mark DM]

WBP ply comes in at 9mm if that would work. If not a timber yard would cut you some Hardwood strips. There's also acrylic sheet at 8mm. If using timber , give the cut packers a good soak in something like ronseal total wood preserver.

 

[Mountaindreamer]

WBP ply comes in at 9mm if that would work. If not a timber yard would cut you some Hardwood strips. There's also acrylic sheet at 8mm. If using timber , give the cut packers a good soak in something like ronseal total wood preserver.

thanks, I like the sound of both options. I wasn't sure about whether ply would hold up over the long term, or rot quickly, hence the suggestion of wood preserver.

 

[Mark DM]

Marine ply treated would last even longer but more expensive.