How to prevent mold in a tropical climate?

Hoping you can help. We moved house a couple of years ago, and my husband - having bowed to the inevitability of my book addiction - let me put up a double layer (as in wall-to-wall, ceiling-to-floor, one set in front of another) of bookshelves, with the front ones fitted with glass doors for added protection of my precious (but only to me) library. Imagine my horror when, having carefully cleaned the shelves and plastic-jacketed my books, I found mold growing on the bookcases! I cleaned the back set of bookcases (which took a couple of months, owing to one kid in kindy, and a new baby in the house) and got to the end, only to find the mold coming back.
Well, I've yanked everything off the shelves, cleaned them, sprayed them with mold killer (sodium hydroxide & sodium hypochlorite), polished them, and am currently re-stacking the shelves. I'm cleaning the books as I go with a damp cloth dipped in a dilute mix of dettol and laundry detergent (I read somewhere that it prevents mold). Oh, and also installed electric dehumidifiers (since the chemical ones weren't effective)
Reading all the expert advice in other topics, what I've done seems a bit harsh, but I'm desperate and couldn't find much advice that helped - it's only just occurred to me to ask on Library Thing. The books are not exotic or ancient; mainly fiction that I've bought in the last couple of decades - but most of them are special to me. We live in the tropics, where the humidity is a fairly constant 97%.

I seem to have erradicated the mold for now (or the visible part of it) - the question is, will what I've done so far prevent it coming back? I really don't want to have to repeat the process every couple of months, especially as it takes a couple of months to get through it.

I'm wondering about the wood used for these shelves. Is it unfinished, has it been sealed or treated in any way? If it's in the grain it may just keep coming back unless something is done.

So, as much as you might like those glass doors, that might be part of your problem. In tropical climates, the next best thing to having a climate-controlled room (low temperature and humidity), is having good air circulation. With the shelves closed in by the doors, you aren't getting that air circulation, so the air in the shelves just sits there and the books stew in it. Open the doors, keep a fan going in the room. If the room does not have air conditioning and if you find that the dehumidifier isn't effective, windows open to let in the breeze might be a better bet, a contrary as that seems. But the dehumidifier is a good step.

The other problem with mold is, once you get it, it's hard to really truly get rid of it. If there are some books that haven't gotten moldy at all yet, immediately separate them from the books and shelves that have been moldy.

There are mold-retardant paints on the market; painting your shelves with one of them may help some. But the comment about the glass doors is very important - still air is the best friend of mold.

You've got a couple of challenges - the glass both makes for an ideal internal environment and provides a condensation point for humidity. As suggested, air circulation is the best approach, ideally with sub-micron filtering. You basically want a balance of temperatures both inside and outside the room where the bookcases live, and you want to control the spores getting inside when unattended. The problem is that once spores are in your house they're difficult to eradicate - even when you clean off everything you're only killing what's currently living on the surface and really setting up the perfect environment for new spore growth. The best products on the market are those with labels called "Mold Control" or similar, which puts a film down that basically blocks new mold growth (both on the surface and underneath). The issue there is that most of us don't want a milky white film on books.

Exterior paint has mildewcides which prevent the growth of mold/mildew, as do paints marked "Bath and Kitchen" made by better manufacturers. That will help prevent mold from growing into the paint, but it only deters surface mold. However it all helps. If you can get some type of external, filtered airflow under the glass that will help most of all as it will both deter mold and prevent differences in humidity (moisture helps "feed" the mold). You would want the in-coming air to be lower, and the exit port to be higher - ideally small fans, both of the same rating, on either end with filters on the inlet. Sounds complicated right?

I'm facing something similar as I intend to use part of a basement space for bookcases in my library. I'm putting a pocket behind the cases that will circulate air throughout with filtration.

Not directly relevant to this problem but this book - http://www.librarything.com/work/7587362/book/15528148
has a note inside the front cover stating "A poisonous insecticidal solution has been used in binding this book."

I'm not sure if I should handle it without rubber gloves!

Wow! Thank you - lots of good advice.

The shelves are wood, covered in veneer, and finished (except at the back where it comes into contact with the bookcase - but no evidence of mold there, as far as I can tell), so once I cleaned the mold off, it does seem to have gone.

I am saddened by the thought of having to give up the doors - I got them installed partly to prevent other people's mucky paws getting on them, and partly because the front cases slide, so I thought they might stop things falling off the shelves. But if it has to be, it has to be. Mind you, there didn't seem to be more (nor less) mold than on the open shelves behind them. Right now, the doors are open. I keep the windows to the room open in the daytime, too, and when I'm in here, I use either the fan or the air-conditioner. The problem with the air-con is that with the heat from the dehumidifiers and the high humidity of the climate, I'm not sure if it'll cause it to start raining indoors (now wouldn't that just add to my problems!). I'm not sure if it'll help or not, but most of my books already have plastic jackets. Haven't had any confirmed sightings of mold on the actual books ... yet. I'm also making sure there's an air gap between the bookcase and books on all side (partly because I'm a bit worried that the heat from the dehumidifiers might get to work on all that paper)

I've only been able to find cleaners that kill mold, not necessarily prevent it coming back (and, yes, they are bath & kitchen products, which seems a bit weird to use on bookshelves)

This was just going to be a simple set of bookshelves to contain my library, so it wasn't stored all over the house, but it seems to get more problematic and expensive every month (without counting the cost of expanding my collection).

Thank you all for your advice. Maybe I should just seal the room and buy a space suit for whenever I want to read ...

Hi everybody,
My wife and I are having the same problem, in Panama City, Panama. High 90s humidity and same daytime temps pretty much all year round. We have an apartment that usually seems to have pretty good airflow... but I am beginning to suspect that stagnant air in the bookshelves themselves is helping to make things worse. Open front particle board (Sauder flatpack) bookcases.

So far, a good dozen or so of our clothbound or leather bound books are showing recurring mould. I've cleaned them with Mr Clean, sprayed them with Lysol, and let that sit. Keeps coming back, usually in about two weeks.

Everybody down here has mould problems. (Nobody told us about them before we moved here, alas. Brain fade on our part, I think. That and being tired of living in high latitudes.)

We've not yet gone to running fans and electric dehumidifiers in each room with bookshelves, 24/7... but I am beginning to think that's what we've got to do.

Any other ideas greatly appreciated. I dread looking at limited edition books (like our fully annotated Narnia) and seeing the forces of evil and chaos taking over.

Help?

I've got one spot in my house that seems to have a recurring issue with mold growth, too, so I did a bit of googling.

I found http://en.wikipedia.org/wiki/Mold_prevention discussing chemical treatments.

Elsewhere, I found repeated cautions against using the outside walls of tropical buildings for shelving books. I don't know how practical that caution is, and I don't live in a tropical clime, but I intend to try several strategies - moving the bookcase away from the wall, drilling ventilation holes in the back, and possibly the rear of the horizontal shelves, front shelving of books, to allow air flow behind. Physical materials that may help alleviate humidity and mold growth in a variety of circumstances are blotting paper, baking soda, cornstarch, activated charcoal, and (strangely) lavender oil.

humouress, I thought about protection from little hands too, as a good reason for doors. My grands always go through a phase of delighting in emptying bookshelves. Had you thought of replacing the glass with screening? What did you eventually do, and did it work?

>6 abbottthomas: Yikes, abbottT! It's strange that the publisher thought to post a caution back in 1938. Bug-free still?

I haven't gone investigating the recesses of the bookcases, but I don't see any blatantly obvious mold coming back (touch wood ;-) ). I have been using my bookshelves a bit more often, desperately trying to keep up with my quota for the 75 book read, although I've slowed down in the past couple of months. So far, we seem to be holding our ground.

>9 2wonderY: No obvious infestation! Given the more relaxed attitudes to poisons in the 1930s, I think it must be something fairly nasty - I certainly don't lick my fingers when I turn the pages.

I've never used this on book. But for walls/bookshelves I would suggest buying pure tea tree oil. I had a leak in my roof and it damaged part of the ceiling and walls. A few cleanings with the tea tree stopped the mold in its tracks.

I have similar problem and live in tropical climate.

I have 3 boxes of valuables books. It has been in there for many years and when take them out to check on them i saw that some of the books have mildew (well i think so, see pics below) grows on them. What is the best way to remove these mildews.

More importantly how to prevent these books from another mildew attack. At the moment i put the books in air tight zipper bag with silica beads. Is this a good way for long term storage.

BTW i live in a very humid country, combating humid is an unwinnable war. I'm from Malaysia.

here the pic, i think it's a mildew though because it looks nothing like mold.
http://i.imgur.com/pYRxgGR.jpg
http://i.imgur.com/uI6E8cn.jpg

"Elsewhere, I found repeated cautions against using the outside walls of tropical buildings for shelving books." - 2wondery

You're not supposed to put bookshelves against exterior walls in *any* climate really because outside walls can experience temperature/humidity changes. There isn't a way for you to move the bookcases to interior walls? Seems like that would be more space-efficient than moving them away from the walls and less work than drilling a ton of holes into them.

An air-purifier might help get rid of mold spores and help circulate the air the room.

All this talk of air circulation makes me wonder if I should get backless bookcases (when I get my own house) and just stick them perpendicular to the wall like in libraries. :P

I think few people live in a house large enough that they can shelve all their books against interior walls, at least few people with more than a couple of thousand books.

I was honestly imagining a few book cases, which is like hundreds of books. Didn't realize we were talking about *thousands* of books. I suppose I should have known people here would have like full libraries. :P

So putting shelves perpendicular to walls might be more practical than moving them against interior walls. Though the bookcases don't look as much like pretty display cases that way.

Once we had a house where we had enough space to be able to have stacks in one room, and also a bookcase divider between rooms. But here most books are on outside walls. It's where we have wall space.

Stacks are a fairly efficient way of shelving books if the space is just for books. Modern movable stacks are even more efficient (but expensive). But if the space is shared with people living, it ends up not very efficient.

We finally ended up moving a lot of books into a basement room, and I have to keep a humidifier in there this time of the year, and a dehumidifier in summer. I try to keep things at about 50%, which is probably a bit high for the books, but seems comfortable for me, and I spend a fair amount of time there.

As mentioned above, the chemical dehumidifiors may help in cupboards, but are totally inadequate for rooms. The electric ones create heat, are noisy, and need daily attention, unless you can connect them to a drain. Ours works well to reduce what would be 75 - 80% down to 50 - 55%, but gets much less efficient if I try to get below that.

If it's any consolation we used to have enormous problems with mold in India during the monsoons, and it would disappear the rest of the year. Any mold getting into your books probably needs the very high humidity, and will not affect them any more if you ever move back to a less wet place. I have books that went through that cycle four times, and don't even smell mildewy. I'm fairly sure my parents threw any books away with large amounts of visible mold.

So, to recap, it was my shelves and bookcases that got mouldy, not (thank goodness) my books, though the books themselves aren't especially valuable to anyone else except me. I scrubbed everything down with a dilute mix of laundry detergent (which seems to have a particular chemical that gets rid of mold), dettol and toy soap and then sprayed it with the strongest mold-killer I could get (which also temporarily slightly affected my breathing tubes). I can't remember whether I polished the shelves afterwards, or not.

The electric dehumidifiers, to clarify, are essentially low-intensity neon tubes (as in tube lights) which give off a little bit of heat, but no light. The glass doors I leave open, sometimes, and close sometimes.

Now, four years later, having been away from my bookshelves for a couple of years, and (naturally) having acquired a few books in the time, I thought it was time to clean the shelves again. The good news is that I didn't find any mold.

On the other hand, the shelves and exposed sides of the books were incredibly dusty. This probably has a lot to do with the fact that ever since we moved in about 6 and a half years ago, one or other of the neighbouring houses in a five block radius has been under renovation or reconstruction (standard practice on purchasing a property - we were guilty of it, too), and with the windows open, the dust blows in. There was also very fine, dense black dust especially on the inside of the glass and around the junction boxes and wires (I suspect they act as electromagnets and attract the dust particles); it has been suggested to me that maybe the heat from the dehumidifying tubes is to blame, and I should turn them off occasionally.

So I have repeated the process with the soapy solution and the mold-killer spray, and hope I remain mold-free.

Now - does anyone have any solution for dust …?

Update August 2017:

Have just completed another cleaning of the bookshelves for dust; thankfully the mould doesn't seem to be in evidence. However, my books do seem to be smelling musty these days. I keep the dehumidifiers on in the back shelves but I've switched them off in the front shelves (having problems with the plugs, since the cases slide). It does feel quite hot in that room already, and I'm a bit worried about the fire risk.

Any suggestions to prevent/ eradicate the musty smell?

The saga continues.

The sliding bookcases became a pain (the wheels disintegrated and then the replacement set - supposedly stronger - disintegrated even faster) so we decided to move the front cupboards to another room - hereby designated 'the library' - and put glass doors on the back ones because, even with the sliding cupboards in front of them, they were incredibly dusty. (I had completely forgotten this discussion, but there are also other considerations like insects and geckos.)

However, having cleaned and polished them, even with new dehumidifiers installed (one at the top and one at the bottom of each cupboard) I found that the three old cupboards have a whitish powdery substance forming on them. Weirdly, it forms in lines though the veneer is fairly smooth. Any ideas as to what it is? Fingers crossed it's not mould.



We had extra cupboards built to fill in the gaps so it's wall to wall bookshelves; they are also cherrywood veneer (but built by a different carpenter) to match the existing cupboards. They - touch wood - don't seem to have the same problem in spite of being right next to/ in between the old cupboards. I read somewhere something about the glue used to stick down veneer causing deposits (but, of course, can't find it now).

>19 humouress: I built a closed box with ozone generator to deal with the musty smell. It may also help with the mold. There are multiple videos on YouTube on how to do that.

>21 dar.lynk: Thanks. Will look into that.

Found this for cleaning/ preventing mould on books:

https://www.greenmatters.com/health-and-wellness/how-to-protect-books-from-mold

https://www.wikihow.com/Remove-Mold-from-Wood-Furniture

Natural mould removers:

https://www.bhg.com.au/natural-mould-removers
https://moldguide101.com/mold-removal-products/essential-oils/
https://lavendertips.com/does-lavender-really-help-against-mold-spores-exploring...
https://greenorchardgroup.com/5-air-purifying-essential-oils-that-kill-mold/

I wouldn't worry about a small amount of additional room heat in your book room from dehumifiers. When my family lived in Central America on a military base, each bedroom closet contained a small lightbulb about 2 inches from the floor --- its purpose was to keep mold or mildew from growing on leather combat boots.