Hi There, I have removed all my kitchen units and exposed the floor which is weyroc (3/4") boarding. The plumber has amended all the pipework for the new sink unit but there are a few large cut-outs in the wall edge of the weyroc boards where the old waste pipes etc were. For me, they want plugged/filled in or covered from the underside. What is the Best material/wood to do this please.I can't get a small quantity of weyroc. But something of smaller thickness or something I can treat would be good to try and use. Thanking you if you can help please.