Thread: Condensation exterior cedar

We recently had our cedar painted and now are experiencing condensation on the siding and exterior windows in the early morning. When it warms up, it disappears.

Is this normal? Should we be concerned about infiltration to the sheathing and insulation? Could this be caused by excessive indoor humidity? No other house around us seems to have this issue.

Our indoor humidity is fairly high right now (52% with AC running) with the temperate climate in the Chicago 'burbs-warm during the day, cool evenings.

Thank you....

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Originally Posted by Handy Mac

We recently had our cedar painted and now are experiencing condensation on the siding and exterior windows in the early morning. When it warms up, it disappears.

Is this normal? Should we be concerned about infiltration to the sheathing and insulation? Could this be caused by excessive indoor humidity? No other house around us seems to have this issue.

Our indoor humidity is fairly high right now (52% with AC running) with the temperate climate in the Chicago 'burbs-warm during the day, cool evenings.

Thank you....

Well, if it is on the siding and the windows then the painting had nothing to do with it. If anything it is due to the home being cool on the inside and it is warmer on the outside and the due points are just right. This the produces condensation.

Thanks, Scott.

Actually it has been cooler on the outside during these "events"., 70's during the day, 50's at night with high humidity.

Except that if similar weather conditions in the past did not result in the same condensation conditions as you are now experiencing.

In which case it could be that the painting of the cedar as changed the vapor transmission rate of the structure through the cedar siding, causing the moisture and vapor to find another escape route.

Yes, it was previously stained/painted.

I don't recall it ever being so noticeable until now, maybe sometimes on the windows, but not the siding.

The condensation occurs only on humid/foggy mornings - dew all around. There doesn't appear to be any more condensation on the outside walls than the windows. Since it wasn't noticeable until the outside walls were painted, is it more likely that the moisture is all from the outside, rather than seeping to the outside surface from within the house? If the fresh paint builds a better vapor barrier, wouldn't this PREVENT more moisture from the interior appearing on the outside walls? I'm just trying to figure out why, on a humid outside morning, our freshly painted outside walls would have more condensation than our neighbor's. At 50% measured humidity in our house, is it at all likely that interior humidity would play a big role in outside condensation, or is it more likely to be higher outside condensation due to the surface conditions of the new paint?

Handy Mac: I probably have been experiencing the same damp nights as you. I doubt that you have a problem. I'm going to guess that prior to your siding's being painted that it was able to more readily absorb any night time water vapor. Once the new coating was applied, the moisture accumulated on the surface since absorption is now not as likely. I too have cedar siding and have had the moisture build up on the surface.

Some of these past nights have had 100% humidity. the other morning our patio was wet from all the moisture. We use a whole house fan at night (low setting) and in the morning the window screens are dripping wet. I really think that you're OK. As we go into Fall I imagine that some mornings you and I will see frost on our siding.

By applying the paint to your siding. the wall can't breath any more. Wood needs air and by painting these area I think you have limited the wall to fresh air. this may over time cause a big problem...

Best

Ron

Originally Posted by Ron Bibler

By applying the paint to your siding. the wall can't breath any more. Wood needs air and by painting these area I think you have limited the wall to fresh air. this may over time cause a big problem...

Best

Ron

Am I reading this right? Are you suggesting that everyone painting wood sided houses for the last 100 years is making a mistake?

As for the OP..... I'm going to guess that you are looking at your siding a lot more than you ever did in the past and are just noticing things more.

New paint just gave you a consistent "collector plate" to observe what has been happening all along except now the moisture collects on the paint rather than soaking into the wood un-noticed and then evaporating later in the day.
Don't worry.

Originally Posted by Ron Bibler

By applying the paint to your siding. the wall can't breath any more. Wood needs air and by painting these area I think you have limited the wall to fresh air. this may over time cause a big problem...

Best

Ron

Oil based paints restrict vapor transmission - not a characteristic of latex paints. Even so, wood siding is not an air tight covering and I've never heard of oil paints being a problem on exterior walls. Where problems can be created is the use of oil based paints and/or vinyl wallpaper on interior walls - that's where moisture problems can be experienced.

Thanks for your replies.

I think we might have a problem.....I noticed the underside, bottom piece of the cedar is tacky, not drying out. It is a latex stain.

I am wondering if we "sealed", trapped the moisture fromt the power washing prior to painting. Will it ever dry out and the paint become firm? It has been a few weeks.

Originally Posted by Handy Mac

I am wondering if we "sealed", trapped the moisture fromt the power washing prior to painting.

Pressure washing prior to painting is generally done wrong. First of all, you're working with a great deal of forced water - very easy to blast water into soffit vents and behind siding. All this water takes time to dry out - couple of weeks oughta do it. Also, any cleaner used during the power washing has to be completely washed away prior to painting.
As for the still tacky paint - I don't know if that could be due to left over cleaner or a concern with the latex paint itself. In any event, you have not sealed the water in the siding or wall.

In the attached, a proper use of a sprayer is shown - down and away from siding joints. Most people will blast up and into for the higher elevations.

Originally Posted by Handy Mac

Thanks for your replies.

I think we might have a problem.....I noticed the underside, bottom piece of the cedar is tacky, not drying out. It is a latex stain.

I am wondering if we "sealed", trapped the moisture fromt the power washing prior to painting. Will it ever dry out and the paint become firm? It has been a few weeks.

Yep, powerwashing can cause a bunch of problems. One good reason that homes should not be powerwashed!

If it was me I would hire a good home inspector who specializes in moisture problems in residential homes. I would say that within an hour or so they should be able to narrow down or even discover the problem or if you really do not have a problem.

Don't forget that your window also have condensation on them and you did not paint the windows!

Spending a couple hundred dollars for some peace of mind, might be just what you need......

I'm with Scott you should employ a moisture expert to look into this issue for you. You stated that you did not have any problems with the home before you paint. Painting can be a bring big problem for home and wood sidding materials. I see it all the time out in California. Homes like air and the more air the better.

Best

Ron

Anyone in south suburbs of Chicago you might recommend? For possible moisture issue?