Whole house insulation/ventilation

[snowman]

This seventy year old snow country two story balloon framed house has ventilation and insulation problems. There are attic vents in the peak of the house, one of which has been enlarged to receive a twenty-inch industrial exhaust fan that we run on summer nights to cool down the house. We install the fan in summer and remove it in winter, replacing it with a perforated vent.

Originally built with no wall insulation, the attic valleys had old paper faced insulation that was also used on the pitch of the roof decending from the attic to the soffit. When we blew cellulose into the walls there was excess that piled up in the attic. We used the excess to further fill the valleys on top of the original paper faced insulation, although that was not done uniformly as there was insufficient excess. We then put down barn board to walk on and covered that with six inches of fiberglass insulation.

Five years ago we installed vinyl siding and vinyl windows. The soffit was originally closed, but we opened it when we installed vinyl siding. The open soffit was then covered with perforated vinyl.

Initially the house seemed to be warmer in the winter after the upgrades, but that effect seems to have steadily gone away.

Now we experience paint blistering on the interior wall on the second floor. This summer we experienced unusually excessive moisture on second floor walls and ceilings. An insulation expert recommended spending five hundred dollars to check for voids in the wall insulation but another contractor suggested opening up interior walls to determine state of the insulation.

We want to replace the existing original roof with standing seam but need to get a solid understanding of the current moisture and ventilation problems before proceeding. Can anyone here help?

[pushkins]

If your running AC during the summer, this should be removing moisture from the home, so if your running AC and still have moisture problems then the problem could be bigger than expected.
Is there a moisture barrier in place between the attic insulation and the room below ? The paper face of insulation batts or rolls is actually a moisture barrier and should always face the heated side (interior side) One thing you never want to do is have two moisture barriers, this traps moisture between them and causes all sorts of mold problems,
How did you get the insulation down the wall cavities ?

[snowman]

AC/Wall cellulose

There is no A/C in the house. Cellulose was blown into the exterior walls over fifteen years ago and we are told it may have settled a foot or more.

Insulation in the attic valleys has been in place prior to our moving in and may have been installed in the 1950's or even earlier. The paper side of the insulation faces away from the plaster to the open attic.

Some of the feedback we are getting strongly suggests we have created a ventilation problem by tightening up the house, but right now we just don't know. We have no problem paying someone to assess the problem but we don't know where to begin. We want to remove all the existing attic insulation, replace it with either foam or rigid, remove the roof and replace it with a standing seam but until we confirm the ventilation problem, that could be a very expensive mistake.

Thank you for your help.

[HayZee518]

pushkins explained that the vapor barrier should be towards the heated area. yours isn't but facing up. there for I would remove the kraft backing or install batt type insulation that has no vapor barrier. you might follow up with blown in to a depth of 12 inches.

[snowman]

The second floor rooms have a forty inch knee wall then the wall follows the roof pitch. The pitch has the same old insulation as the flat of the attic, but is not accessible down to the soffit without removing the roof. We are concerned that the cellulose in the walls may have absorbed moisture as a result of moisture condensing on the pitch and running down to the wall. Paint is blistering on the interior wall at the bottom of the pitch.

[pushkins]

Check to see if there is any space between the roof sheathing and ceiling of the upper level, if there is insulation in there there should also be an air gap . In other words the insulation can be touching one of the surfaces (roof sheathing or ceiling) but NEVER both at the same time, there must be air access to allow any moisture to escape. In your case if the insulation is jammed between the two when the roof gets hot the insulation (having little or no airflow) starts to sweat, this could be causing your moisture problems as you mentioned.
Insulation blown into wall cavities especially after the fact from above is always a difficult task, anything running across the stud cavity like electrical cables etc...has the real potential to stop insulation from getting to where it needs to be. Add this on top of the fact that insulation will settle and compact down like you mentioned, over time even caught up insulation will fall past most obstructions.

Can you get to any of the open wall cavities behind the 40" knee wall, there should be access to this area.

[snowman]

Air gap

Yes we have at least two inches of air space between the insulation and the sheathing at least as far down as can be seen with a flashlight. We cannot see whether or not the valley at the bottom of the pitch opens cleanly into the soffit.

There is no access to wall bays as the kneewall is the exterior wall. In our last old house there was space behind the kneewall where we could store boxes etc. but this house is a different design. If we needed to inspect the cellulose in the wall for moisture or mold we would have to remove a section of the plaster & lathe to access the wall stud bays.

Is there any quick effective way to determine whether we have proper and sufficient ventilation from the soffit through the roof vents? Is it possible we have restricted airflow through the inside of the house such that moisture can't get out? Could we have prevented moisture from leaving the walls by installing vinyl siding over the clapboards?

[pushkins]

The easiest way for most people to check for airflow is by using an incense stick, now before you laugh it's also the safest way, there is no flame and only smoke so the danger is very limited. Hold the stick in the area your wanting to test and look for where and how fast the smoke moves, this will tell you how the air is moving and it's speed. The better the air movement the better the circulation (naturally). This test can also be done by someone holding the stick outside just under the soffit, look for the smoke being sucked into the soffit and or the smell of the incense stick in the attic.
When doing these tests try to restrict any doors to the attic, you want to make sure that the smoke is not being pulled into the upper rooms, ideally what you want to see is the smoke coming in the soffit and heading towards the roof vents.

When the siding was added was there anything put under the siding like fan fold insulation, tyvek etc...etc...
The roof insulation...is it faced with paper and if so what side is the faced side facing?
I know you mentioned that there is some insulation in the attic with the paper facing INTO the attic, this is not good as it traps the moisture IN the attic. When the paper faces the heated or cooled room it traps the moisture in the room and then is dealt with by the AC removing the moisture to cool the room down or heat using the moisture to warm the room.
In your case the faced side of the paper is pointing towards the roof sheathing, then if you have shingles there will be tar paper on the roof, this is also a moisture barrier, so now you have trapped the moisture.
Even if you change the roofing to a metal roof you will need to do something about the insulation paper facing the wrong way, metal roofing is obviously a moisture barrier.

[snowman]

There is nothing between the clapboards and the siding. The vinyl siding was placed over the clapboards without 3/8 foam or tyvek.

What puzzles us is that the attic insulation has apparently been wrong for fifty or sixty years yet the problems we are experiencing have only shown up recently.

Using common sense suggests to us that the changes in the house have occurred because of something we have done that has changed airflow or trapped moisture.


Thank you again for your help. We have a better understanding now of what we are dealing with. We will check the airflow as you have suggested. We will remove all the existing insulation and insulate correctly before putting on the new roof.

[pushkins]

There is nothing between the clapboards and the siding. The vinyl siding was placed over the clapboards without 3/8 foam or tyvek.

What puzzles us is that the attic insulation has apparently been wrong for fifty or sixty years yet the problems we are experiencing have only shown up recently.

Your right, you added the vinyl siding that is a moisture barrier unto itself because it is plastic and impervious now you have faced paper trapping the moisture between it and the vinyl siding.
However if there is adequate air movement then this problem can be overcome at least in the attic. Until you remedy the faced insulation facing the wrong way you won't correct the paint issues that are related to moisture.