go to a local cabinet maker and get apiece of 32mm HMR chip board (it will have a green tinge)to put underneath. Make sure it is in line with the back of the plinth (kick board) so you can install the new plinth over the top. unless it floods then you won't have a problem. This is the standard practice for 90% of all kitchen companies in WA.

Yes I am a cabinetmaker by trade and yes I know what I am talking about. Not in the trade anymore so no I can't get some for you.

Do not do as Nauli suggested as the door will then not line up with the others. If it is FULLY integrated you can raise the door to be above the controls on top of the DW also.

Watch the overhang on the bottom of the door as it will not open if it hangs down to low.

DO NOT use solid timber as if it gets wet it will swell more than chipboard or MDF.

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RS RA
The more people I meet the more I like my Dog!

12.463 1/4 mile, not bad for an old school Liberty [DECEASED]

MY08 Liberty Tuned by STi