We have two gumtrees over a largish deck - 10 x 4 m with 120mm Merbau. I had 80mm before it was redone. The gumnuts and sticks and leaves are a total pain! The trees are nice but all year they make a mess. Tannin is another issue requiring constant cleaning.

Been thinking of a sealing strip to keep out the crap so I can blow it off at least and not have to scrap out the gaps which are about 3mm wide. The gaps run away from the house.

Is this a good or bad idea?

  • If you make the gaps wider will things fall through more easily? Then, just a clean-out once a year to ensure that no nuts are sprouting into trees that want to grow through your deck (could be a cool look, if that's what you're after), instead of regular clean ups on a weekly or monthly basis.
    – FreeMan
    Commented Feb 15, 2021 at 16:12
  • Ty, we had wider gaps on last version the bigger nuts get stuck then! Sticks too, argh !
    – steveowen
    Commented Feb 15, 2021 at 20:11
  • I don't see a question up there.
    – isherwood
    Commented Feb 15, 2021 at 21:49

2 Answers 2


I'd consider how much rain it gets before thinking of filling the gaps. You could be swapping one problem for another if the deck doesn't slope sufficiently away from the house to properly drain.

My first plan would be
A leaf blower (or even just a yard brush) for the dry stuff, followed by
A pressure washer for what's left. A bit of decking cleaner in the soap container every so often would preserve its appearance too.


I like the gaps, my deck is treated pine but I think air circulation in the 4 to 8 mm gaps helps to slow rot ( now 25 years old with a few replacements). I have holly ,oak, and pine to supply crap. I blow every couple weeks and about once a year I clear cracks with a large blade.

  • yep, I have a blade with a roller on a paint pole that runs in between to pull them out.
    – steveowen
    Commented Feb 15, 2021 at 21:37
  • Yes, if the filled gaps can't dry sufficiently, the boards will rot. But then again, if the gaps are full of wet tree crap, the boards will rot also. First thought was something like this drainage mesh, but that might get gummed up with the smallest crap. keenebuilding.com/products/building-envelope/walls-and-siding/…
    – Blobfish
    Commented Feb 15, 2021 at 23:44

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