Framing a darkroom against concrete wall

[John Layton]

Oh...dust from the old ceiling sounds like trouble. You could "sister up" the old beams with some dimensional lumber, leveled on the bottom with some string stretched between low points - then apply sheetrock. Or...you could simply staple some heavy (3 mil) plastic up on the existing ceiling to seal it off from dust, which might actually make it easier to push some of this plastic upwards between existing beams to accommodate enlarger heights.

[archphotofisher]

Painting the ceiling is a very good idea, vacuum joists, floorboards, etc. then give it a nice thick coat of paint, a couple of coats, this will seal the dirt in, I have done this in a few buildings.

[Gary Beasley]

You might want to put the ridgid foam between the joists and caulk the seams. Then you could paint. The insulation will reduce the noise a bit and keep the dust down.

[domaz]

You might want to put the ridgid foam between the joists and caulk the seams. Then you could paint. The insulation will reduce the noise a bit and keep the dust down.

Thanks Gary- I was actually looking into that, "cut and cobble" method of insulation they call it. It's probably a lot easier to paint once the foam is there, or else I would be fighting with countless nails that penetrate the subfloor.

[Ron McElroy]

Our house was built in 1912 and also has a low basement ceiling. Like your house the floor joists are uneven. I used oriented strand board for the ceiling and walls. It has worked great and well the with high humidity the basement had before getting air conditioning down there.

[Robert Opheim]

You really will want to insulate and finish your darkroom. You will want it heated and you will want to control the moisture in it. I would suggest that you dig out and waterproof (not damp-proof) your concrete wall on the outside face. You may need to provide a drainage matte, free draining gravel and a perforated drain pipe in filter fabric that outlets down slope. I know retaining wall water leakage is basements in Seattle and Western Washington are a common issues. You have valuable photographic equipment that you don't want to get mold and mildew in and ruined. A good friend of mine did not insulate and heat his darkroom and most of his equipment and books, were ruined.

[Leszek Vogt]

I'm with Robert above, since that is what I had to do to keep the space downstairs dry and without fears of potential leaks. Had to do this all around the house. Sure, it is a production, but one sleeps better at night knowing.....

Les

[RandyB]

Here is my 2 cents on this subject. When I built my last house I knew I would make a darkroom in the front left corner of the basement. The standard waterproofing for cinder blocks is to coat them with a thick tar like coating. I wanted some extra protection so before they did the back fill I covered the entire outside wall with 6 mil plastic all the way down to the drain gravel. Several months after moving in I started building my darkroom. I coated the inside wall with 2 coats of waterproofing, after that dried several days I added 2 layers of 6 mil plastic then built 2x4 walls flat against the walls. The walls were anchored to the floor and ceiling joists. Insulation was added then another layer of 6 mil plastic and finally put the drywall up. After mudding and sanding the drywall, 2 coats of mold killing primer and 2 coats of very high quality 18% gray paint I was ready to add counters, sink, cabinets and stereo system. The concrete floor was also given 2 coats of waterproofing and then full sheet linoleum was laid down. This is what I did, I hope it gives you some ideas. It was a lot of work but well worth it. Good luck. RB

[Drew Wiley]

Randy - Asphalt emulsion as a wall sealant is pretty much an antique method. The correct type probably doesn't even exist anymore. Far better products have existed for decades now, and are themselves cement base. Some like Drylok are pre-mixed with latex binders for convenience, but the powder forms are less expensive. At once I gave seminars for foundation and waterproofing contractors, municipal and military users, tunnels, dams, and reservoirs, etc. Some brand names might have changed, and I don't try to keep up. There are also silane and siloxane sealants which penetrate masonry and are triggered by internal alkalinity to form a permanent compound; but these are more specialized and ordinarily require an acid pre-treatment (not healthy to do in internal situations). A third major category is made for hydroscopic bentonite clay applied to the surface on sheets; but this type is more geared to big projects, not DIY applications, so hydraulic waterproofing cements like I first mentioned are the most realistic.

[RandyB]

Drew, that particular house was built in 2000-2001. I am sure California has much tighter/advanced building codes/practices but here in the South things can be more lax. In fact the local codes inspector expressed frustration at the number of DIY projects that refuse to get a permit or even follow basic common sense codes. They have limited power to make a land owner follow the codes. Things are improving, some years ago the State revised many of the codes making them tougher and imposing fines for the offenders. I haven't built a new house since the 2000/2001 house so I don't know what todays standards are for exterior waterproofing cinder block walls are but I can assume the builders will use the absolute cheapest product even if it is not the best.