« Cork Tile Flooring | Main | Reclaimed Heart Pine Flooring »
Vapor Barrier Paint
You want to install hardwood flooring in your basement but hear you can't do that because of moisture problems so often found in basements. A vapor barrier can be the solution to that dilemma. And vapor barrier paint is one alternative for basement moisture problems.
Vapor barrier paint is yet another weapon in a homeowner's arsenal to fight against damage caused by water vapor. Vapor barrier paint is made by many paint manufacturers in different grades, as we will see. There may be reasons you can't or won't use traditional vapor barriers for your floors before installing wood or carpets in your basement. That's one cases when vapor barrier paint is great.
>
It is important to understand how water vapor acts in order to understand the uses of water vapor barrier paint. In a process called convection, warm air always moves toward colder air. Thus, during cold months, the warm air in your house is constantly seeking to escape outdoors. Warm air also expands, putting more space between its molecules compared to cold air. Expansion allows warm air to hold more water vapor. When this warm air encounters the cooler surfaces of your home, such as exterior walls, it cools down and contracts, squeezing out water that collects on the cool surfaces.
Underslab and in-wall water vapor barriers are designed to keep water out of your home. They defend against groundwater seepage, rainfall, and floods. But having water form inside of your home is also bad. It is here that water barrier paint plays a role in protecting your home's interior surfaces.
Water vapor barrier paint is often applied to drywall walls and ceilings in attics, where warm air tends to rise. Without water vapor barrier paint, the warm air would release its water inside of the walls and ceilings, where the water would saturate the insulation and framing. This water damage can render insulation useless and cause rot in structural members.
Not every household paint or enamel is an effective water vapor barrier, though. In order to qualify as water vapor barrier paint, a product must attain a Perm rating less than 1.0 under the ASTM D1653 Test Method for Water Permeability of Organic Coating Films. The lower the Perm number, the less water vapor the barrier paint allows to pass during a given amount of time at a given temperature and humidity. When shopping for water vapor barrier paint, ask for it by name and check the Perm rating which should be on the can.
Water vapor barrier paint is often sold as a primer, to be applied under a final coat of a different paint. The primer is generally sold in white. It can be colored to some extent without degrading its water vapor barrier properties. Usually, the can's label will tell you how many ounces of pigment can be added to a gallon of water vapor barrier primer. The instructions will also state the maximum surface coverage of a gallon, and whether one coat or two are recommended.
Water vapor barrier paint is also used directly on concrete floors. Products such as Aquapel, made by L & M Construction Chemicals of Omaha, Nebraska, penetrate porous concrete and chemically bond with it to seal out water vapor.
Water vapor barrier paint is not a substitute for other water vapor barriers when they can be installed. In some cases, such as cinder block construction, it is impossible to install conventional water vapor barrier sheeting behind exterior walls. In these cases, a high-grade (low Perm) water vapor barrier paint is essential.
Older homes in need of water vapor barriers are also good candidates for water vapor barrier paint. It would be a bad idea to try to pull back the insulation in an old home's ceiling and try to install plastic behind it. It makes much more sense to paint the ceiling with a good water vapor barrier paint.
Water vapor barrier paint complements other forms of water vapor barriers and can be a valuable tool in insulating older homes.
Comments
Forgot to mention, the house in question is a bank-owned, and they are refusing to pay or do any repairs, so we are asking them to take off the price of some of the major mechanicals.
Looking through some DIY sites, it looks like the best route (for our money) is to lay down some heavy duty tarp, place a real dehumidifier, use the vapor barrier paint, insulate, then put on the plastic, in that order, as we get money to do so.
Cost of supplies: $2500 Cost of doing it professionally: $16600.
Andrew at July 28, 2008 06:04 AM
Ewww......... I take it you got a written estimate or two to show the bank? That should motivate them to come down some.
I wouldn't think that a dehumidifier is necessary, so long as you have a vapor barrier put down - remember too, that it needs to go up the sides some too. That's usally put down before any insulation as well so that the insulation doesn't get soggy. If you have ventilation holes, keep them open, it really does need to breathe under there. We do close ours up in the winter though - and have screens over them to keep little critters from having access to under the house.
Good luck!
The Flooring Lady at July 28, 2008 10:00 AM
We recently purchased a 1950's house built on a concrete slab. It appears that there was water damage in one of the bedrooms in the past where cork tile floors are stained and buckled and a french drain has been dug outside the windows. The air quality in this room has tested with elevated mold levels so we are removing the tiles, washing with bleach solution and sealing any cracks we find in the concrete. After this we intend to install carpeting to make the room usable until we can afford wood floors in the next few years. Should we apply vapor barrier paint before carpet? Any other suggestions to minimize moisture issues?
marge at August 22, 2008 11:25 PM
Yes, a vapor barrier would be in order, glad French drains have been added! I'd suggest something other than carpeting in a basement - they always attract moisture in the air (humidity) and wind up smelling musty - not to mention the health concerns that go along with this.
I'd suggest a laminate floor until you can save up for a wood floor. Either Lowe's or Home Depot has a 50% clearance going on right now (sorry, I forget which!), so this might even be more economical than carpeting anyway. Good luck!
The Flooring Lady at August 23, 2008 12:31 PM
I like The Flooring Lady's suggestion of laminate flooring. I also think linoleum would be a good choice, and maybe even cheaper. Engineered flooring could also be nice, like bamboo or other beautiful would that appeals to you.
If you have major water problems there read the articles in the moisture proofing section of this site. I just read several articles and find them valuable for helping in your situation.
Tim at August 23, 2008 03:59 PM
Dear Flooring Lady,
Thank you for your great wisdom on so many topics; you have really helped us to narrow things down and weigh the options...So, my question is this: We are putting in engineered 5" plank floors with a top layer of Chestnut wood in our bathroom and kitchen. We are two fairly careful adults, so we will wipe up, but recognize the inherent danger of moisture in these locations. From our research, it seems that the people who have done this and who remain happy with their choice have taken extra steps to seal the floors. What do you recommend in this regard, and how many layers should we put on? Thanks very much...
Sue Burrell at August 19, 2009 10:55 AM
Sue,
At this point I would call a local professional who can assess the humidity in your area as well as in your home.
The Flooring Lady at August 19, 2009 03:37 PM
I am considering finishing my poured cncrete basement walls. I have been advised to glue hard foam to the walls and build a wall frame in front of this insulation and then drywall the frame.
I am contemplating leaving a gap at the floor and elevating the foam insulation and the frame wall about 2 inches off the floor with cncrete bricks.
What is your assessment of this approach? Where would the vapor barrier paint be applied.
What suggestions do you have for changes in this approach?
Jim Stephens at August 23, 2009 02:27 PM
Jim, I'm going to address your questions backwards from how you asked them. Not knowing just how moist your floor is my answer may not help, but I'm going with what you have given me.
The article addresses your question, as would the paint can. For sure you need to paint wherever the soil touches the concrete, but painting everything is really the best approach.
Now, tell me why you are elevating your foam wall insulation, and supporting it with brick? I can't know if it's a good idea until I know why you are doing it. It seems it may be overkill, but I'll know more later. And when you glue the foam insulation consider using Bostik's Best glue. Whatever glue you use make sure it won't melt the foam.
You didn't address how you were going to finish the walls once you insulated and vapor-proofed them. If you are going to use drywall as the finish, with your plan you don't have a good way of attaching it to the wall. Why not consider nailing or gluing 2"x2" strips to the walls, insulate between them, and then you can attach the dry wall to the wood strips.
The Flooring Lady at August 24, 2009 10:19 AM
The gap at the bottom of this system pays attention to letting any moisture escape that might be found between the wall and insulation.
A 2 x 4 wall will be built and placed next to the hard foam and covered with drywall painted with vapor barrier paint.
I am unsure where the moisture might come from: through the poured foundation wall or from condensation on the wall from interior air.
I was going to insulate between the studs in the wall with kraft back fiberglass. It has a lot of embedded energy cost to make it. I may use blown cellulose which I am going to use on a Habitat house we are building.
The whole idea is avoid any mold.
Thanks for the advice on the glue.
jim Stephens at August 26, 2009 09:52 PM
