I want to make a cover that masks the pond foil along the edges of my parents' fish pond which is 2.2m x 3.8m.

I'm planning on using quarter sawn boards out of larch, 11cm wide and 3cm thick, joined by stub tenons.

Will this be stable enough as far as warpage is concerned?

Any other suggestions?

  • QS wood is inherently stable and less prone to warping, assuming you're using well-dried stock it should be any particular problem but regardless of the cut of boards the quality of the stock is always relevant. One other thing, for an exterior project larch may not be a great choice since it can be classed as only moderately resistant to decay (unless it's treated of course).
    – Graphus
    May 18, 2018 at 16:15

1 Answer 1


Will this be stable enough as far as warp is concerned?

The term 'warp' can cover a lot of issues. Your boards may readily cup, twist, bow, or crook due to the repeated exposure to water and uneven drying. enter image description here

The amount and type of warping will depend largely on the arrangement of the grain as much as how the boards attach. In general a short stub tenon at the corners will do little to resist most of these categories although it will resist cupping at the intersection areas even though it may occur further toward the middle of the boards. Your best may be to select individual boards with very straight grain. You can reduce cupping by selecting boards with vertical grain orientation relative to the wider board dimension. You might also want to mount the this trim frame to block risers rather than directly contacting the pool liner directly to maintain some airflow around the frame allowing more uniform drying.


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