Bathroom wall surfaces

Hi folks, Im a total newbie. I have just bought a small 1918 house in Detroit. I am redoing the 2nd floor bathroom which is just under a dormer. We are putting the bathtub in a corner where it will be in some places inches from the roof and wall of the building (I mention this because it Will be below freezing soon outside) We have taken down the plaster (but left most if the lath). I want to tile around 3 walls of the bathtub. My question is, what are good natural alternatives to sheet rock, backerboard, tape and mud. I need to get this done soon so I don't want anything that needs to cure for more than a couple of days. 2ndly the other walls in the bathroom are plaster underneath but have multiple layers of fake vinyl tile and who knows what all else on top. I need to smooth coat those walls as well and am looking for a good non toxic product. I am in Detroit and would love a nearby supplier. Any thoughts would be greatly appreciated. Ps--it doesn't have to be 100% green.

Julia Diamond wrote: My question is, what are good natural alternatives to sheet rock, backerboard, tape and mud.

Wow, that's a tough one. One alternative is a tough, rigid styrofoam, maybe the 2"-4" thick stuff that is used to insulate concrete pours, but it's certainly not a natural alternative. Tile goes down pretty well onto a plywood backer, but then again, plywood is not something I think of as "natural". Since you want to get it done soon, I think you are going to have to settle for expedient at the cost of being natural.

I've heard good things about lime plaster in bathrooms....

If it doesn't have to be 100% green, what is your desire outcome and criteria? I would guess waterproof is number one on the list for both outcome and criteria, but what else?
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Hi folks, thanks for all the replies. My interest in green is that it makes me sick to pollute the planet-- thats about my whole philosophy. So, I want to go as green as I can. My confusion with the bathroom is that on one hand you want surfaces to be waterproof and on the other hand you want them somewhat permeable so the walls can "breathe". I'd like to use a natural insulation (at my last house I used chopped up recycled denim--i can't remember the name), but since this is going to be near water I thought maybe this would be too mold friendly??? But maybe not??? So far what I have looking in through my bathroom from the roof is roof shingles, then wood, then about 5" of air, then the remaining wood laths from the interior wall. So if someone were me--what would you use? Am I supposed to put some kind of flashing against the inside of the roof? Or is that not necessary? I'm thinking i would use insulation, then sheetrock, then backerboard, then tile. Do I have it right and if so are there natural alternatives to those items. Also, someone mentioned lime plaster but I think that takes time to cure? Thanks a bunch.

A natural line plaster would normally be the answer to your question for what to put onto lath, however natural plaster won't work in your 2-day time line.

Do you have good insulation behind your lath?

You know tiling your outside walls is going to make those walls freezing to the touch even with good insulation in your walls just saying, tile is a cold winter companion.

A good site for this is - http://www.mychemicalfreehouse.net/2013/02/a-non-toxic-bathroom.html

MgO board is a cementitious wall board ideal for those with chemical sensitivities.
It is non-toxic, VOC-free, and a very impervious to mold. If you have a wood-framed
wall it will be easy to attach the board to that. Good brands are Dragonboard, Mag Board and Magnum Board

You can plaster, paint or tile over MgO walls. Here are some tips on using plaster.
If not painting, the MgO boards would need to be primed.

Hi Jami, thanks for the response. My next task is to locate the mgo board in detroit-- do you have any leads. I don't have insulation but I do want it and am trying to avoid fiberglass so would appreciate leads there as well. Thanks again.

Some pics and a diagram would always help describe this better

From what I gather the dormer is above the bathroom on the second floor. How tall are the exterior walls you are placing the tub next to? Inches to the roof? Is this an attic remodel? The dormer has fixed glass or what type of window? Is there a bathroom fan? If not install a well insulated one w/a flapper for the size of the room and use it.

Lime would not be an issue here since other than having to keep it wet a couple times a day 2-4 weeks, and in a functioning bathroom that is easy. It is labor intensive but since you already have the lath an option. Lath is not cheap. If you are not familiar with lime get on the American Lime Associations website and read their publications. It is an acquired skill not a quick DIY.

Your roof is 2 x 6 lumber, the cavity should measure 5 1/2 ". You could use denim insulation it dries fast, has borax or boric acid as an anti fungi and fire retardant. I'd recommend mineral wool in a bathroom. It will provide R-21, in Detroit roofs s/b R-38+. If you have the head height add Roxuls (1-2)stagger 1.5" boards for another 3" R-6-12 to the ceiling I'm guessing is cathedral/vaulted? There is no flashing req'd on the underside of roof sheathing other than if you install a fan follow the mfg and silicone caulk any existing fan.

Walls should be insulated to code min there is R-20, if not Jami is correct they will thermally bridge into bath tiles, use fiberglass surround unit if you can. Tiles use a hardiboard cement board rather than Georgia Pacific's backer board with acrylics. You can also use the plastic you take off the walls to thermally break the wall studs and/or add some Roxul IS boards.

https://energycode.pnl.gov/EnergyCodeReqs/index.jsp?state=Michigan

I recommend removing the vinyl tiles over plaster. For quick, known, DIY, etc.... and easily accessible I'd use a fiberglass faced and taped gypsum board like GP DenseArmorPlus: http://www.buildgp.com/densarmorplus-high-performance-gypsum-panels No microbial producing paper, FG just like mag board. I'd steer clear of DragonBoard or any Magboard from China too many quality control issues and little tech data to prove it's sustainability especially in wet environments. Foreverboard here in NY is an option and the only US mfg if you fully understand mag board and the industry. Not DIY friendly. Better to go with a higher grade gypsum w/FG like GPs, etc. Due to expansion and contraction use it everywhere, all walls. It has a perm rating greater than 10, can provide some humidity buffering up to 5% it's weight....not as great as lime or clay but not bad. To get more add a mud hot coat using 1:1:2 (mud: type s lime: sand (80 grit jagged edge mason: mud: (Wespac, Murphy). Use a high perm siloxane sealer, lime wash or mineral silicate paint like ROMA or Heim.

I've been to this facility in Chicago before they are doing some interesting things with hemp/lime not far from you: http://www.americanlimetechnology.com/

Hi Terry, thanks so much for your input. I will go with the gypsum boards as you suggest with a lime wash on top. Somebody else mentioned no tile next to exterior wall so I will skip the tile on that wall and stucco with a lime wash. I will use the mineral insulation as suggested as well. I have a question. I converted a garage into a guesthouse in los Angeles. For the bathroom walls including surrounding the tub, we just "stuccoed" over the drywall--just like you would with exterior stucco-flashing, chicken wire and then three coats (brown, scratch and top coat) and then I painted with old fashioned oil based enamel paint on that--12 years later its still beautiful and impermeable-- what's the difference between stuccoing and plastering? Here, plastering is such a big expensive production-- why not stucco and what is the difference? Ps- will try and make it to Chicago to see what's going on at that lime place.

Hi Julia, sounds like you are confused about a few things. Let me see if I can clarify although my writing skills are not the best bear with me.

Somebody else mentioned no tile next to exterior wall so I will skip the tile on that wall and stucco with a lime wash.

Depending on the type of “stucco” or a better term for interior walls “plaster” and its cement percentage, it can thermally conduct or “bridge” across a material as much as tile. I suggested using fiberglass bathtub surround unit if you have the head height since it does not conduct heat as much. I also suggested taking the plastic off the other walls and using it on the studs and between a plaster lath or tile backer boards since plastic is not very thermally conductive to create a ‘thermal break” if you will between outdoor air and the inside of the bathroom. The same would apply behind any tub or combo units, install the backer or gympsum boards and plastic thermal breaks to the studs. Another thermal break I suggested is Roxul Comfortboard IS rigid insulation boards, in addition to above can really insulate this bathroom well but it will not be cheap. Sounds like your biggest problem as far as insulation will be the dormer glass so it may not be worth spending a lot of money on the wall and roof insulation.

I have a question. I converted a garage into a guesthouse in los Angeles. For the bathroom walls including surrounding the tub, we just "stuccoed" over the drywall--just like you would with exterior stucco-flashing, chicken wire and then three coats (brown, scratch and top coat) and then I painted with old fashioned oil based enamel paint on that--12 years later its still beautiful and impermeable

It is hard to compare a bathroom in LA to Detroit without knowing all the details. I can tell you just because things look good on the surface does not mean they are good under the hood. If you want a breathable wall “impermeable” is the wrong word, as is using oils on interior plasters, that can create vapor barriers and reduce drying.

Commercial stuccos are good for exterior wall applications since they contain high levels of Portland and other cements that make them super strong but impermeable. The higher strengths are also driven by code to meet structural requirements for bracing walls.

Interior plasters do not need so much cement or density to hold up to the elements, nor meet as high structural requirements, often none. They are therefore more “permeable” for breathable walls.

There are a lot of contributing variables to both but that is the basics.

I think you’d have a good plan to install the DenseArmorBoard w/a hot mud coat and lime wash everywhere, sealed with a siloxane sealer you can get local concrete supplier until water beads up on the surfaces. Take care of the roof and exterior walls insulation as described. You can then tile the tub surround if you want, or, go with a permeable interior plaster like lime or American Clay has some good high perm products but more expensive than the DIY hot mud coat.

Hi terry, I understand what you are saying and I am going to write down all your suggestions and clarify what my options are. I really want to thank you for taking the time to instruct me. As I get closer to fully pulling down the walls--im pulling down the laths and foregoing the plaster-- I will post a photo of the situation and then hopefully it will be more clear. There are no dormer windows-- I don't think I used that word properly-- but there is definitely a slope to the ceiling. My plumber has gout! So we are delayed a bit. Going on day 5 without a proper bathe...

Have you seen the thread Dale's Living Bathroom ?