The beadboard sheets that I've used are molded so that one-half of a groove runs along each long side of the sheet. When you put two pieces side-by-side they form a groove, disguising the seam. If there are small gaps you can caulk, but don't use too much--you might lose the detail of the groove.

This post was edited by mama_goose on Mon, Dec 8, 14 at 7:43

No low grade mdf in a bath. If you want wainscotting, do tongue and groove or pvc.

What are you doing about te improperly constructed shower?

I respectfully disagree.

I might have posted this story before. One winter we had a lot of ice, and because I was having a difficult time keeping the sidewalk clear, I made a sign to warn the UPS people. I used a scrap of pre-primed (on one side) mdf beadboard, ap 18 x 24", which I leaned against the front porch rail, unprimed side with the writing, out. That piece of BB was exposed to snow, rain and ice, all winter, with no deterioration at all. Frankly, I was surprised.

Of course, it wasn't exposed to steam, so you might consider that in your decision.

for the seams, you paint a stripe of whatever color your beadboard is, on the wall so that if you have a gap between sheets it will be less noticeable.

There are a lot of different quality materials out there. The low quality MDF or masonite v-groove stuff, I wouldn't put anywhere. It crumbles while you are trying to install it, and it doesn't have the overlap lock built into it.

The vinyl coated MDF, maybe. If it looks "pre-primed" on the front and MDF on the rear, it might really be a paintable vinyl coating. Or just a good quality primer. That usually has the lap built into it, but still would need to be bridged with a bead of caulk as even it will be subject to moisture intrusion in a bath.

The solid vinyl, sure. It's exterior approved, which ought to be good enough for a bath. It would be my top choice, as solid wood tongue and groove will expand and contract a lot in the presence of so much moisture and would really need to be primed and painted on all sides before you intall it.

Here's what happens when the edge of MDF beadboard gets wet.

That's a mess. In my last reply I actually typed, "I assume you aren't putting it in a shower or tub surround." But I deleted that line because I didn't want to insult the OP. I didn't think anyone would put it around fixtures where water is sure to puddle.

Yes, caulk the seams and use a good primer and paint. Sounds like the OP is putting it just on the walls.

I installed what the OP is talking about in my kitchen, but used a vinyl trim piece along the bottom with everything thoroughly caulked. It runs right behind the sink and I'm not worried about it. I am mindful about the water though. The face has a thick coating and it will be primed and painted when I finally get around to it.

This post was edited by sheesharee on Tue, Dec 9, 14 at 11:28

I would not use particle board beadboard in a bathroom. It's usually the lower pressure, less moisture resistant glue kind. If you can actually find the specs, and it's based ona 40lb+ pressure substrate with melamine resins instead of the usual formaldehyde ones, then that might be a possibility. Too much steam, and usually poor ventilation in most baths for the tyical particle board stuff. It's asking for trouble.