I understand using ACQ for the 2x12 stringers, but you should have used 2- 5/4x6 ipe boards for the treads. that ACQ is gonna cup, and split. It's not too late.

steve

I agree with Steve. You cut yourself short but not using ipe planks for those treads. If you are already experiencing problems, its just going to get worse. The last factor that should sway you is that the very green ACQ 1) repels sealers worse than ipe when it is new and actually needs to "age" before it will accept anything penetrating. 2) rarely loses that green tint and will never acceptably match your ipe.

I can easily replace the treads with something else later on if they don't work satisfactorily. IPE is not available locally, and the quantity required would way too small to ship.

I built a similar set of stairs about 15 years ago using 2X12 pressure treated treads, and although there is some slight cracking as there always is with treated wood, it is not enough that I have been concerned about it. Is ACQ treated wood worse about this than the older type?

I'll probably just paint them with brown porch paint after the wood has aged a few more months. The other steps hold porch paint very well, and the steps don't have to be exactly the same shade as the deck.