Treated lumber in a darkroom - will it cause problems with paper?

[DAP]

Hi all,

I am in the process of ripping apart my current darkroom and rebuilding it from scratch. It is located in the basement and the walls are crumbling cinderblock walls that tend to get damp...overall this provides a nice little dungeon effect. I would like to finish the darkroom w/ water+mold resistant drywall and was planning on using treated lumber for the furring strips that sit between the drywall and the basement wall. I want to avoid using regular untreated lumber because I am scared that it will provide a good base for a mold explosion. Does anybody know if the chemicals in treated lumber will have any negative effects on photographic paper that is stored in the darkroom?

Thanks in advance.

 

[largeformat pat]

G'day,
They used to use arsenic as a preservative in treated pine. This has stopped in many countries. They use a copper based material now. This will bleach out in water and in soil. Your dry wall would be best if you used a compressed concrete sheeting (fibro) To provide a barrier you could place plastic membrane on the wall before fixing the wall sheets. If you propose to tile this will give you even better isolation. I would recomend painting the walls of the basement with a water proofing membrane as well. I would steer away from tar based, I would look at an epxoy.
Hope this helps
Pat

 

[largeformat pat]

Also I would look around for a cheap fridge to keep the materials stored. This will extend the life of your materials.

 

[Ian Tindale]

"Negative effects" - such as solarisation?

 

[Pinholemaster]

Do you want to breathe the air from the off-gassing of treated lumber? Think about your health before photo supplies.

They now make anti-mold drywall.

 

[bdial]

Pressure treated behind drywall or cement board probably wouldn't be a problem. Polyurathane trim cut into strips might be an alternative. A vapor barrier and insulation might be a good idea too.

 

[fotch]

Many methods used in the past have been found to make the problem worse. It would worth your time to research for up to date info on Mold prevention and construction techniques before you proceed.

An ounce of prevention is worth a pound of cure.

Good Luck.

 

[lns]

I had mold in a tiny area within my finished basement walls 5 years ago, caused by a pipe behind drywall that was leaking unseen and thus unbeknownst to everyone. Some forms of mold are toxic; some people are very sensitive to molds; and remediating it properly can be very expensive.

If the damp cinderblock walls you mentioned are exterior walls, you might want to investigate exterior waterproofing (and/or rebuilding) before you do any interior construction. I would hesitate to drywall over a leaking wall, no matter how "mold-proof" the drywall is supposed to be. If the mold grows inside the wall, believe me, that's a bigger issue.

-Laura

 

[Larry.Manuel]

You may want to consider plastic lumber, sold in my area for deck construction. No chemicals. Also, beware of mould growth, as others have suggested. Perhaps a dehumidifier will remedy that. Under the right conditions, mould seems to grow on anything.

 

[removed account4]

They now make anti-mold drywall.

"green board" is used in bathrooms &C ...
but i don't think it is anti mold, just a bit more water resistant
than traditional sheet rock ...

 

[Rick A]

A company called United Gilsonite Labratories(UGL) makes a couple of different paint on wall sealers for the express purpose of keeping water and moisture out of basements. I painted their water base (they also have a solvent base) on my walls and it works very well.After that you can use treated furring strips and mildew proof drywall that uses a fiberglass wrapping instead of paper(which invited mold). If you feel you must, then use an addiyional vapor barrier of polyethyline sheeting between the masonry wall and furring. This is not an inexpensive fix, but then is your equiptment cheap and expendable? The newer treated lumber is less toxic than the old copper chromate, arsenic(CCA) treatment, which was very toxic.
Hopes this helps. Its what I've been using for over fourty years on construction sites.
Rick

 

[fotch]

If you feel you must, then use an addiyional vapor barrier of polyethyline sheeting between the masonry wall and furring. T...............been using for over fourty years on construction sites.
Rick

From what I recall reading in Fine Homebuilding and other sources, this method is no longer considered the way to deal with basements.

Get as much info as you can before you proceed. You may need to address the moister on the outside first. Use a dehumidifier in any case.

JMHO

 

[DAP]

Hello again,

I would like to thank everybody for their suggestions (both on the public forum and via private messages). It sounds like mold is more of a concern than any kind of outgassing from treated lumber.

As far as preventing mold I am planning on re-landcaping my lawn (to drain water away from the foundation), and installing a drainage system in my basement. I just purchased a product called "squidgee" - it is kind of like a gutter system that allows accumulated water in the cinder block walls to escape in a controlled fashion - this should cut down on moist walls. I have also made a personal vow to be better about cleaning out my roof gutters I also have an old dehumidifier in the garage that I will dig out to place in my darkroom. As of right now I'm going to hold off on putting up any drywall and see if these changes keep the wall sweating at bay (if the walls remain dry for a couple of months I'll think about drywalling w/ DensArmor Plus boards and treated lumber furring strips).

I'll update this thread down the road to let you know how it goes (I suspect that there are others out there with the same problem/concern).

Thanks all,

Dana

 

[Andrew Moxom]

I plan to use a drywall type product call Hardi-backer. It's available in 1/4 or 3/8" thickness and is what I used for my main shower stall in my bathroom. It's better than the wire mesh/cement boards used for most wet areas in bathrooms etc. I handles like drywall, does not crumble like cement board and can even withstand immersion in water without breaking down. It will NOT mold as it has no particles in that that mold needs to grow. If you use this stuff, you will not need to use treated lumber.

You place the backing boards on top of a normal rubber membrane liner, and paint a PVC sealer on top if you plan to tile over it. The sealer is bright pink when you paint it on, but it's a water based PVC type membrane paint that dries to a blood red. This will seal EVERYTHING out and can be tiled right over. The sealed surface has some give in it so that tiles won't crack if there is some minor expansion or contraction due to humidity in your house. I plan on just putting stainless steel splash board all over my wet area in the darkroom when I build a more permanent darkroom space.

 

[Jan Pietrzak]

Dana,

I just came in from doing some painting in the new darkroom. So hear goes.

1. treated wood most states/counties/cities make you put in treated wood with construction 'fact of life'
2. do a mold/moisture seal on the wall. If you have mold clean it up and seal up after it. The boat people have a mold/retarder they use on boats, it works.
3. if you feel you need a barrier?sp use Tyvec/Tyveck/sp then dry wall.
4. if you have a damp basement. Get a de-humitifier, and a heater.
5. Not sure what else to say. So back out to paint some more in the darkroom.

Size 9' 6 x 15' 4 12' sink I need to epoxy/paint

Jan Pietrzak

 

[Rick A]

From what I recall reading in Fine Homebuilding and other sources, this method is no longer considered the way to deal with basements.

Get as much info as you can before you proceed. You may need to address the moister on the outside first. Use a dehumidifier in any case.

JMHO

Some people read about things --The rest of us do them.

 

[fotch]

Some people read about things --The rest of us do them.

Yes, there are people who act first without thinking.

 

[Marcus S]

Make sure that you have no water build up outside of your basement first. Sometimes a larger downspout that will divert the water away from the house is all that is needed. A barrier of gravel about a foot wide will keep also keep the water away from the basement walls. Of course a proper tar membrane on the outside of the basement walls will also do its part. Protect the outside before you do anything on the inside.

From the rainy West Coast of Canada,

Marcus

 

[George Collier]

I live in the South US (as you can see) and I have freestanding dehumidifier in my basement, which drains to a floor drain. The walls are brick (1920's vintage). I don't have water seepage, but the basement would be rather humid without the dehumidifier.
I used normal pressure treated 2x4's against the wall and floors, with normal construction studs in between. I used green drywall on the wet side, and normal drywall on the dry side, both painted several coats. This was 20 years ago.
I noticed after a few years that negs kept in the darkroom formed a fungus of some kind, which took a lot of work to remove. So I keep nothing in the darkroom other than equipment and chems.
No matter what precautions you take, I would recommend not keeping paper, film, negs, or even the enlarger lenses in the darkroom, unless you really don't have enough space somewhere else.