Garage MDF shelving how to seal to avoid mildew

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Last summer I fitted out the garage with lots of metal frame shelving units, with 5mm MDF as the shelves. The garage has no leaks etc., but is unheated and it has been a damp winter. Just discovered that all the bare MDF has grown horrendous black and green mould. The undersides of the shelves look like velvet. All other materials in the garage are OK, just the MDF is a mould magnet.

So when it is dry (so I can empty the garage to get at the shelves) I will clean off the mildew with a bleach solution. But what can I treat the shelves with to prevent this happening again. Hopefully something ecconomic and easy to apply, I have a lot of shelves. Bare MDF is a disaster.
 
more ventilation
the mdf has a well pressed hard surface that why it attracts the moisture
you seal it it will still attract the damp
 
Yes I know how lack of air movement can allow condensation and then mildew to form, but my garage is pretty drafty. It is not just mouldy in the corners, in fact where items have shielded the shelves (and limits air movement if anything) there is less mould. We get a lot of mists, called "mizzle" locally, venting let it in!

MDF was just a bad material choice, the particle board and pine in similar positions shows no sign of any mildew. But MDF is commonly sold with metal shelf racks now, am I the only person with mildew? What kind of bulk sealent can I try? It does not have to look pretty just be easy to apply and reduce the MDF damp absorbsion.
 
dont think it will help if the moisture is attracted by the mdf giving it a plastic cover will make no difference
is the mdf the only place that attracts the damp ??
 
MDF is the creation of the devil in person.....I'm surprised it hasn't sagged badly by now?
How about replacing it with ply or pine slats?
John :)
 
dont think it will help if the moisture is attracted by the mdf giving it a plastic cover will make no difference
is the mdf the only place that attracts the damp ??
Yes, just the MDF.

But no sagging. It is on a steel rack system, supported around all edges and in the middle, you know the free-standing shelf units sold everywhere now. Works great except for the mould.
 
Presumably an oil-based finish, typically gloss, will make the surface much easier to keep clean, and should seal it quite well, assuming you prime and undercoat well. I would be inclined to use oil-based all the way, though I'm sure someone will correct me.

What about a simple clear varnish for quickness?
 
I need to mention the scale of the problem - I have 35 shelves 120x44cm MDF, both sides to treat that's 37sqm. Just washing off the mould is going to be a task!

I have no worries about esthetics, the bare MDF looked fine until it sprouted fur. If it just looked funny I would leave it, but move anything and I get a face full of spores:(

So prime and OB gloss, not going to happen. Throw some polyurethane varnish about, maybe, something that will cover in one coat? Something that comes in a big pot too. Would PVA seal? I know it makes things had to paint, but it doesn't matter here. Fence treatment perhaps?
 
You wouldnt need to do it all at once though. You could tackle a few shelves at a time so you dont have to empty everything. Obv take longer...
 
You could try a water-based fence preservative, very quick drying and clean, if you're interested in a quick cheap job. The Cuprinal water-based fence PRESERVATIVE DOES actually soak in well, and DOES actually last on outdoor fences, so if you've got a tatty fence it may be very useful. (The cheaper non-preservative fence stuff is rubbish, doesn't soak in properly, and comes off easily.) I think the preservative will seal the MDF reasonably well, and for one coat should look qite reasonable too.
 
Thanks Sparkwright. The last lot of fence painting I did was a real bust, didn't even last the year, and I have not painted a fence since as it seemed pointless. Must have used the non-preservative kind, I can't remember now. But the preservative kind sounds like something I can slosh about.
 
Yes, and trust me, it does work on fences (preservative type). Water-based simply because it's so much easier for clean-up.

That regular fence treatment you see for sale everywhere can be seen coming off in the rain.
 
Bump. I have the same issue. Did anyone resolve this?[GALLERY=media, 107477]IMG_20220108_130715 by Sanyam Kaushik posted 8 Jan 2022 at 2:04 PM[/GALLERY][GALLERY=media, 107476]IMG_20220108_130712 by Sanyam Kaushik posted 8 Jan 2022 at 2:04 PM[/GALLERY][GALLERY=media, 107475]IMG_20220108_130708 by Sanyam Kaushik posted 8 Jan 2022 at 2:04 PM[/GALLERY][GALLERY=media, 107474]IMG_20220108_130705 by Sanyam Kaushik posted 8 Jan 2022 at 2:04 PM[/GALLERY][GALLERY=media, 107473]IMG_20220108_130701 by Sanyam Kaushik posted 8 Jan 2022 at 2:04 PM[/GALLERY]
 
I have similar racking. The manufacturer advised coating the shelves with Danish Oil if they were to be used in a damp area.
 
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