Vapor Barriers
#1
01-29-11, 03:48 AM
Vapor Barriers
Ok, I'm a little confused about what exactly qualifies as a vapor barrier. I know that certain paints are good for this, but what specific materials are used for a vapor barrier?
#2
01-29-11, 04:39 AM
Welcome to the forums! As far as I know, no paint will suffice as a vapor barrier. Vapor or moisture gets behind paint and it's toast. Now, in a shower situation, you can use a product like Redgard on your concrete backer underlayment to help, but a good solid vapor barrier of 6 mil plastic is always a better solution.
Fill us in on your ultimate goal. What is your project? Which room? How big? What will your final wall covering be?
Fill us in on your ultimate goal. What is your project? Which room? How big? What will your final wall covering be?
#3
01-29-11, 04:51 AM
Originally Posted by chandler
Welcome to the forums! As far as I know, no paint will suffice as a vapor barrier. Vapor or moisture gets behind paint and it's toast. Now, in a shower situation, you can use a product like Redgard on your concrete backer underlayment to help, but a good solid vapor barrier of 6 mil plastic is always a better solution.
Fill us in on your ultimate goal. What is your project? Which room? How big? What will your final wall covering be?
Fill us in on your ultimate goal. What is your project? Which room? How big? What will your final wall covering be?
#4
01-29-11, 05:37 AM
I'm going to let our paint guy chime in on any knowledge he has on paints. He'll be along shortly. As far as breathing, all houses need to breathe. I doubt your house has a breathable barrier on the outside, such as Tyvek or Typar, due to its age. Vapor barriers are generally installed between the framework and the final wall covering to keep moisture behind the wall and breathing to the atmosphere.
Generally what shape is the plaster in? Is it worth repairing and saving? Would you be better served in the long run by gutting the plaster and starting again with drywall? That way you could insulate the walls properly as you go. Just some thoughts until we hear from marksr.
Generally what shape is the plaster in? Is it worth repairing and saving? Would you be better served in the long run by gutting the plaster and starting again with drywall? That way you could insulate the walls properly as you go. Just some thoughts until we hear from marksr.
#5
01-29-11, 05:42 AM
While not as effective as a plastic vapor barrier, solvent base paints/primers can be somewhat of a substitute for a vapor barrier.
From your description of the work being done on the interior, an oil base primer would be in order anyway. You should be aware that the peeling paint might contain lead!
On the exterior while an oil base primer does the best for priming the wood, we've found that on the older houses that don't have a vapor barrier it's best to use a latex primer as it will let the house breathe some. Too good of a paint job on the exterior of these old houses often results in premature paint failure
Just read Larry's post, he makes a good point about gutting the plaster! Not only does that allow you to update the insulation, you can also inspect, replace, move or add on any electrical. A lot more work but probably worth the effort.
From your description of the work being done on the interior, an oil base primer would be in order anyway. You should be aware that the peeling paint might contain lead!
On the exterior while an oil base primer does the best for priming the wood, we've found that on the older houses that don't have a vapor barrier it's best to use a latex primer as it will let the house breathe some. Too good of a paint job on the exterior of these old houses often results in premature paint failure
Just read Larry's post, he makes a good point about gutting the plaster! Not only does that allow you to update the insulation, you can also inspect, replace, move or add on any electrical. A lot more work but probably worth the effort.
#6
01-29-11, 05:45 AM
Originally Posted by chandler
I'm going to let our paint guy chime in on any knowledge he has on paints. He'll be along shortly. As far as breathing, all houses need to breathe. I doubt your house has a breathable barrier on the outside, such as Tyvek or Typar, due to its age. Vapor barriers are generally installed between the framework and the final wall covering to keep moisture behind the wall and breathing to the atmosphere.
Generally what shape is the plaster in? Is it worth repairing and saving? Would you be better served in the long run by gutting the plaster and starting again with drywall? That way you could insulate the walls properly as you go. Just some thoughts until we hear from marksr.
Generally what shape is the plaster in? Is it worth repairing and saving? Would you be better served in the long run by gutting the plaster and starting again with drywall? That way you could insulate the walls properly as you go. Just some thoughts until we hear from marksr.
Yes, fully aware of lead paint possibility and precautions are in order concerning its removal.
#7
01-29-11, 05:58 AM
Then, undercut the cracks and fill with a product like Rock Hard Putty by Durham's, sand and prime and paint as Marksr said. He gives good advice on breathability as well.
#8
01-29-11, 06:02 AM
Originally Posted by chandler
Then, undercut the cracks and fill with a product like Rock Hard Putty by Durham's, sand and prime and paint as Marksr said. He gives good advice on breathability as well.
#9
01-29-11, 06:05 AM
I've always used a setting compound like durabond to repair plaster. Both durabond or rock hard are a bear to sand so it's best to do a neat job and then dress it up with regular joint compound - it's easy to sand 
#10
01-29-11, 06:17 AM
Originally Posted by marksr
I've always used a setting compound like durabond to repair plaster. Both durabond or rock hard are a bear to sand so it's best to do a neat job and then dress it up with regular joint compound - it's easy to sand
#11
01-29-11, 03:51 PM
Energy Savers: Vapor Barriers or Vapor Diffusion Retarders
This site discusses "Vapor Barriers" and does mention that most paint coating will impede mosture flow.
This site discusses "Vapor Barriers" and does mention that most paint coating will impede mosture flow.
#12
01-29-11, 03:58 PM
Yep, aware of that. But what I'm really wanting to know is what specific materials are used as vapor barriers. I have heard of plastic being used between the insulation in the attic, but what kind of plastic?
Also, where else do you need a vapor barrier? Basement?
Also, where else do you need a vapor barrier? Basement?
