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Mastershredder 03-18-2007 11:55 AM

Question about attic moisture
 
Hi,
The wife and I put a bid on a new house and we just went through it
with the engineer. This house is a split level, and while checking the
attic crawlspace above the master bedroom, he noticed that the plywood
on the roof looked a little damp and there was mold growing on the
wood. The insulation is blown in and whoever did this never installed
any kind of vapor barrier. Now my questions are:

1) How hard would it be to install a vapor barrier? I know everything
has to be sucked out, then the barrier has to be installed, then new
insulation has to be blown in. This sounds pretty tricky since the
only access is the attic crawlspace and I don't believe the joists
would handle a lot of weight.

2) I don't believe I saw any soffits on the outside of the house.
Would adding soffits and making sure there was adequate airflow in the
attic correct the problem?

I know we're going to be busy taking care of a lot of things when we
move in, so I'm not going to have much time to take care of this
stuff; and I want to get this taken care of ASAP.

Does anyone know approximately how much this would cost to have it
professionally done? We might be able to get this cost taken off of
the offer. Thanks for any help!

Darylh 03-18-2007 12:28 PM

1) How hard would it be to install a vapor barrier? I know everything
has to be sucked out, then the barrier has to be installed, then new
insulation has to be blown in. This sounds pretty tricky since the
only access is the attic crawlspace and I don't believe the joists
would handle a lot of weight.
Vapour barrier can not be put in after the fact ( ceiling finish aready installed).Vapour barrier is installed on the warm side before the ceiling or exterior walls are boarded.
2) I don't believe I saw any soffits on the outside of the house.
Would adding soffits and making sure there was adequate airflow in the
attic correct the problem?
You for sure want to put in soffett vents, there should also be roof vents in as well. You have to have ventalation up there and you are going to want to remove the mold.

AtlanticWBConst. 03-18-2007 01:46 PM

Quote:

Originally Posted by Mastershredder (Post 37410)
.....he noticed that the plywood
on the roof looked a little damp and there was mold growing on the
wood. The insulation is blown in and whoever did this never installed
any kind of vapor barrier.

If the plywood is damp = You have a leak on your roof. If it has mold, then it has been leaking for some time now....
How old is the roof? Was the roof visually inspected by someone getting up there and walking around? The proper repair with this is to address the roof leak, not a vapor barrier. See next point...

Quote:

Originally Posted by Mastershredder (Post 37410)
.....
1) How hard would it be to install a vapor barrier? I know everything
has to be sucked out, then the barrier has to be installed, then new
insulation has to be blown in. This sounds pretty tricky since the
only access is the attic crawlspace and I don't believe the joists
would handle a lot of weight.

You do not want to install a vapor barrier up there, if there is one up there already. As stated by Darylh, you should already have one facing the warm area. If that is the case, then you DO NOT want to add another one...
See this link regarding attic insulation:

http://www.powerhousetv.com/stellent...577.hcsp#P-4_0

Quote:

Originally Posted by Mastershredder (Post 37410)
.....
2) I don't believe I saw any soffits on the outside of the house.
Would adding soffits and making sure there was adequate airflow in the
attic correct the problem?

Does the roof have a ridge vent installed?

If you don't have soffits, then you must not have any overhanging eaves on your roof line.
By the sounds of it...it would be difficult to 'add' soffits without re-framing the roof line.....

If you do infact have a small eave/soffit, you can install small circular or rectabgular vents.
See the link below:

http://www.cornerhardware.com/howto/ht076.html

AaronB 03-19-2007 05:32 PM

I am almost 100% positive that you dont have a vapor barrier, since most products used for this purpose are not true vapor barriers, but vapor retarders.

If the mold and dampness is over largee sections of the roof deck, and it is not leaking when it rains, you may well have a water vapor problem. Key is to determine if it caused from household water vapor or roofing problems.

If you do not have a vapor retarder on the warm side of the insulation (you should be able to tell from the attic space when you remove the insulation), you could remove the existing insulation, and have a 2# closed cell spray polyurethane foam insulation system installed, which isa vapor barrier and air stop at 3" in depth. 5" will give you the R 30 required.

Hope this helps.


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