Expert: Labman - 12/14/2005

Question
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Followup To
Thanks.

I am actuall planning to use blue board. I guess it has to be taped too, plus plastered. Then painted using conventional products. Will there still be VOC and out-gasing through the walls a month or two after? Doesn't even something insignifant as tape continue to out-gas for years?

Thanks

Question -
Mr. Labman:

Could I ask you about shellac? Is it a 100% vapor barrier?  I am planning on installing new blu board plaster walls and then wanted to use shellac to kind of stop out-gasing from the boards and tapes into the house. Is this a good idea? Would it block all kinds of gases completely? Is it bad for the interior air that the walls would not be able to breath?

Thanks

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Thank you. Is there anything stornger than the tape that would hold smell and gas from the oil to come through the holes in the floor. Is there a special material maybe plastic that can be put to cover it. I can afford to put anything, especially in the room right above the tank, as I am there for a month and don't need to use this room. Even if something is very thick.

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Thank you again. I am going to replace dry walls starting with the bedrooms and then see. Does tlinseed oil that is on my walls or even was on the floor produce VOC? Is what I smell from linseed oil a VOC? Is it in the same category as harmful VOCs?

I also have a related question. I can smell oil in my oil tank that is used to heat up the house and hot water. I know that is a VOC for sure. Is there a material I can tempararily put on my floors to prevent these gases from coming to the apartment I am staying at. SOmething like a vapor barier meterial that can be put in one room or two relatively easily, as the floors in some of the rooms have gaps so that the basement and oils tanks are seen.

Thank you again very much.

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Yes. This VOC must be in limited amounts but it is VOC that will NEVER go away because of linseed oil properties, correct?

I also don't think there is anything that can block VOC gas completely, even shellac. Won't this oil-produced gas or whatever gas that is going to continue be produced find its way through anything (I understand in small quantitties)? Plus will shellac adhere well to the wet surface? I understand that leaving this paint inside the wall is going to result in softening of the wall as this paint will eat up the wall towards the inside and oouside.

So is it the fact the every oil evaporates VOC? Even wheat germ oil that is healthy (in very small amounts)?

Mr, Labman, what state do you live in?

Thanks.

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Thanks. So, when I smell odor in my house now from this paint that contains linseed oil, what does actually evaporate in the air 3 months after? Does this oil out-gas? Does it out-gas VOC or other gases or particles?

Thanks.


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Thank you. I have not complained yet. I am trying to figure out how to replace my dry wall (2,400 sq ft house) ASAP and at a minimum expense. I am trying to figure out how and where to move my family.

Could you please tell what coat of shellac is? Is it guaranteed to stop whatever linseed oil and this paint evaporate? Where is is all going to go? Outside? Is there a risk in leaving mositure and wet paint inside the walls?

My main question: what does this linseed oil and zzero VOC paint evaporate as it produces some kind of odor? Is this a gas? Can it be harmful to a newborn and a person with the infected liver?

Thanks


Thanks

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Followup To
Question -
Hello:

This is a person who have asked you about linseed oil on numerous occassion, specifically about it not been able to drive on a brand new hardwood floors.

Could you please tell me what it is? Does it produce VOC? Is linseed oil something people it as I can't imagine linseed oil that goes on the floor could be consumed as a salad dressing?

As you know I had problems with not drying / curing floors and I have same with interior walls. I suspect the wall paint I bought contains linseed oil. Do you think it is possible to use a primer and paint that can serve as a vaport barrier for the wall paint I have that has not dried / cured? Is there a downside in leaving "wet" paint inside? Will it try to drive through the outside walls?

Thanks
Answer -
Linseed oil is one of many natural oils.  They are all somewhat alike, containing long chain molecules with an acid group at at one end.  Three acid groups are combined with glycerin to form the oil molecules.  Most of the natural oils have 18 carbon chains and contain various levels of unsaturation.  Unsaturatuion means some of the carbons only have one hydrogen instead of 2 leaving less stable double bonds.  Conventional wisdom has the unsaturated oils healthier for us, except for the artificially partly hydrogenated ones that come out a different shape from the natural ones.  Naturals have a shape called cis.  The others are the dreaded trans you may have heard about.  Linseed oil contains fairly high levels of unsaturated fatty acids.  I guess refined enough, it can be eaten.  I tend to stick to soybean or corn products.  Less oil is best of all.  

Films go from liquid to solid through 2 process, evaporation of low boiling materials and chemical changes.  The double bonds can also react with oxygen creating links between molecules.  The oils are too high boiling to vaporize much.  Splatter water on your stove, and it dries up.  Oil or grease, and you must clean it up.  Refined linseed oil has very little in low boiling components that do vaporize.  It will react with oxygen and slowly harden.  Adding lead and other metals speeds the process.  It can also be chemically treated to increase the drying rate.  For most applications, there are better products today.  Linseed oil may be hanging on because it is a cheap byproduct of linen production.  

Now, your gummy, sticky walls.  I may have already suggested ripping the drywall off and replacing it.  That would create very little VOC until the painting step.  Removing the mess with paint strippers likely would be more expensive and mean moving out of the house until done.  Guess new drywall would be messy too.  You could put a conventional paint over what you have.  Likely the linseed would continue to harden under the new paint.  Paint needs a solid surface under it.  The new paint would be tender and mar easily. The oil could bleed into it, and soften the new finish too.  A coat of shellac could stop that, but once again, a large quantity of VOC.  One last thing.  Heat accelerates the process.  Try applying your hair dryer to the wall.  

Have you complained to all the consumer protection agencies about this?  
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Shellac comes from tree sap.  In chemistry, like dissolves like, also bleeds through, etc.  Shellac doesn't fit in with much else at all.  Nothing is like it.  It was the classic solution to keep knots from bleeding into paint, and making sure anything else under a coat of paint stayed under it.  Whatever the problem, shellac would seal it away.  Unfortunately, it is applied as a solution in alcohol which provides plenty of organic vapors.  Once dry and the room aired out, the VOC is gone.

Your walls may still be a mess, but VOC shouldn't be a problem.  Any solvent, including water, is long gone.  There will always be some decomposition going on until the material hardens, but the rate is so slow it shouldn't be a problem.  Even if some odor persists, there isn't enough of it to hurt anybody.

I hate our litigateous society, but in this case, sue somebody.    
Answer -
What you are smelling may not be the oil itself.  Most of the vegetable oils contain the same things just in different ratios.  Each has a distinct odor from unique compounds present in very small quantities.  What comes off drying linseed oil is a VOC, but if I ever saw any report of what it is, I have long forgotten.  Anything left after 3 months must be very limited amounts.  
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I think I have mentioned the inverse hockey stick before.  In any process, product will come off rapidly at first, but slow down as the amount left decreases, eventually nearing nothing, but never quite reaching it.  Some of whatever is still coming off will continue.  Very little of that will permeate the shellac.  It will be forced into the way and likely eventually outside.  Any unoxidized oil will continue to be absorbed into the paper surface of the wall board and the pores of the gypsum beneath.  I don't see that hurting anything.  

The shellac should spread out and dry on the oil.  Any mechanical stress will pull the shellac away along with the outer layer of oil.  Still think replacing the drywall may be the best idea.  Hire a contractor, give him a house key and take a vacation.  

My geographic location remains hidden.  
Answer -
Your nose only detects what makes it into it.  Things must volatilize before you can smell them.  As I have explained, much of the smell from materials such as linseed oil are not the oil itself, but small amounts of more volatile material. They are VOC's.  As an example, you are familiar with the smell of natural gas, however it contains very little except methane, which has no smell.  The gas from the older fields contained enough other material to give it a strong smell.  Today, much of the gas has material added to warn you of a leak.  You smell it, not the gas itself.  

The oil tank does have a vent, but I doubt enough ever comes out of it except when the tank is filled to make any difference.  I guess you could have the vent piped outside.  It maybe a little pipe coming up out of top of the tank, over and down.  

If there are gaps you can see through in your floor, it might be better to plug them permanently, leaving cold air, mice, and radon in the basement.  Duct tape would work temporarily.  
Answer -
What sort of holes are we talking about?  Are they where pipes come through the floor, or used to?  You could go to Lowes, Home Depot, etc. and buy one piece of white aluminum soffit or fascia trim.  You can cut them with a sturdy pair of utility scissors.  Cut squares an inch bigger than the hole on each side.  Cut a hole to fit the pipe along with a slot to slip it over the pipe.  Neatness counts, it must fit the pipe very closely, but some of that can be done by bending a little down.  Pick a low VOC glue, maybe Elmer's, and glue them in place.  Elmer's isn't that great of a glue for that, but it doesn't need to be held very well.  I guess you could use small nails, but the glue will seal better.  This is a fairly permanent repair.  You can lay flooring over it, and nothing will get through it.  It stoped the mice in my house.  

If they are long cracks between the boards, caulk may be the best.  
Answer -
Shellac might be counter productive.  Drywall, drywall tape,  and drywall mud are mostly solid except for a little water.  They give off very little VOC.  Nothing is an absolute barrier, but shellac does keep lower molecular weight organic materials and water vapor from coming through it.  However, as applied, it contains large quantities of VOC.  Most of it comes off quickly, but I am afraid a month after applying it you may have more VOC coming off from it, than the drywall and other components behind it.  

Answer
There are 2 kinds of tape.  Some of it is just paper with no more that traces of VOC.  The fiberglass mesh stuff has some stickum on it that might have a little more VOC, but again very little.  A conventional latex paint as I have said before does have some VOC, if fact worst stuff than solvent based paints.  Still, after a few days, there is going to very little left to come off.  Even in the winter in a modern, well sealed house, what continues to come off will never build up to more than a trace.  Your cooking may put more VOC into the air or even your body.