You'll still end up with mildew in the holes and at the bottoms (underneath the plastic piece)...sorry. I'd not introduce any more nooks and crannies for the mildew to take hold. Every two weeks isn't bad. :)

Good point, javiwa, that I hadn't thought about. Two weeks isn't bad, but not having mildew at all would be better.

Well, sorry to burst yet another bubble, but THAT'S not going to happen (unless you stop using that particular shower!). On the upside, looks like you have a beautiful shower space there. Here's a bonus to NOT drilling holes: you won't have to scrub off the hard water buildup that's guaranteed to accumulate down there.

I don't like my niche, only because I feel I have to clean it everyday following my shower, like I do the rest of the walls, because water pools around the bottles. I don't have mildew, and I don't have many bottles stored on my niche, because of the cleaning I do to maintain a mold free area. I instead keep them in a plastic basket on the shower floor. The niche is a waste for me because of the high maintenance. I think that if you clean off the shelf every day or so it would make a big difference.

Could it possibly be a problem with the shelf material? I often see things being advertised as mildew-resistant. Since the self is easily removed, maybe try contacting the manufacturer to see if they have introduced a better material. If that's not an option, would a spritz of white vinegar after each shower help?

I dry the shower after I use it which takes a couple minutes and there has never been a sign of mildew in a year.

Even with my regular old enamel tub with the shampoo bottles just standing on the corner, I get mildew if I don't lift 'em up and wipe it down regularly. I can't imagine that changing the material of the shelf would make a difference.

I would drill the holes into the shelf. And like you thought use a piece of wood under the bottom to make the blow out less pronounced. We often need to drill holes in shower caddies, shower column and shower seating just for this reason.

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We found that the fold down seat shown here trapped water in the bottom bracket. To stop that we drill a few holes under from below. Now water does not collect there. Can you see the holes?

What?

No?

Exactly the point.

I love my niche that's at the far end of the tub/shower alcove. It doesn't get any direct water but the base on which bottles sit is ever so slightly angled to drain, but not enough to not feel level. In one year of daily use, no sign of mildew anywhere for which I'm extremely grateful. I don't exactly dry everything off as Pal does, but I do squeegee the tile surround religiously. I think what helps a lot is a window above the long wall of my tub which is open year-round.

Air flow - the secret ingredient in multi family construction. In every condo I work on there is air flow behind the walls and ceiling of the bulk heads and shower walls. Chance? I doubt it.

Mold can not grow in the presence of air flow. Air also speeds up evaporation.

I'm helping out with a large home build in the US (designing the steam shower space) and the clients home has to be easily a 10+ million dollar build. They have hired and air quality engineer and this is the first time I have worked on a project with one.

I hopefully will learn a lot over the next 12 months!

Do you leave the shower door/curtain open after your shower and keep the bathroom fan running for 30-45 minutes? That's what we do in our windowless bathroom, and have had no mildew issues in 1-1/2 years.

While I don't squeegee the entire shower stall, we do squeegee the door and glass wall each time we shower. The shower door is always open and the exhaust fan runs for at least 30 minutes.

I've attempted to keep a minimum of items on the grab bar shelves, but.... I have shampoo and conditioner, face wash, two kinds of body wash (alternate days) and shaving cream. On his shelf, DH has two kinds of shampoo (alternate days) and body wash.

I bought the shelves from my nephew who owns a hardware store. I'm going to ask him if I can get shelves with some sort of anti-mildew property. If I can't, then I'll ask him if I can get replacement shelves. If I can, then I'll drill holes in the shelves. If it doesn't work, I'll replace them.

Last time I cleaned the shelf, I wiped it down with dishwasher soap. I did not rinse the soap off. I hoped that leaving a thin film on the shelf would act as a mildew retardant. It didn't.

Thanks for all the thoughts and suggestions.