Replacing some floor boards in boathouse

[Scoot]

A few of the floor boards in my mo-in-law's boathouse have started to get soft and feel "spongy". I'm going to replace them. I tore out the top boards and found another set of boards underneath that were also going bad. I pulled all of them and will replace them. What kind of boards should I use to replace them? Is green treated lumber ok for this or is there a better option? This would be lumber that would be exposed to plenty of moisture, wind, sun, etc...

[BoxMN]

I'd probably use grn trt myself, but if you are going to be setting anything that is alum or thin metal on it, be careful. I built a fish basket out of grn trt (extra from other project) and after about 4 years the galvanize mesh that I used deteriorated right where it was touching the grn trt. So the stuff is corrosive to some metal.

Not sure exactly what kind of grn trt it was, but it was stuff used for my stairs to the lake. So be sure to use the grn trt screws too

[NoWiser]

Green treated is probably the most economical. Another option would be one of the maintenance free decking materials (like Azek) out there. It would be a nice looking alternative that's easy on the feet (no slivers) but the price can get high real quick if it's a big area you need to do.

[Scoot]

Thanks guys- I'll use green treat. Jim, I'd think about composite options if it was a bigger section, but this is just for a patch job. When the whole thing comes down and we have to do a major overhaul, I'll use composite. I replaced her deck a few years ago with composite decking and it's great! Expensive, but great!!!

[fivebucks]

Take care of that boathouse so it does not all have to come down. I am pretty sure, in MN at least, that if you do a tear down you will not be able to rebuild it. They don't grandfather you in on a rebuild, just repair and keep the same footprint.

[BoxMN]

Currently anybody can do a 120' shed if it is 20' from lake, I believe. Used to be more, but it changed I think about a year or so ago.