I live in the Houston, TX area and have a home for sale. During a home inspection prior to the sale (which subsequently fell through), the inspector noted that the ivy growing on one of the exterior walls should be removed to “prevent damage to the brick.” He also noted higher than normal moisture levels were recorded inside the home on the wall opposite the ivy, and implied that the ivy may be causing the excessive moisture. I cannot imagine ivy causing excessive moisture, and given that the brick is in good condition, doubt the ivy would be damaging it. Would anyone have any idea of a definitve source I could go to understand the effects of ivy (or plants in general) on a home? I would like to be better prepared the next time a home inspector visits my property.
Thanks –
JB
Replies
Agreed.
In the warm, humid climate of Houston, brick walls, if not properly mated with a framed wall, can become a reservoir of moisture that finds its way into the framed wall, but I can't see how ivy alone would be the cause
If the HI observed elevated moisture levels in the wall with a pinless meter, those findings should possibly be backed up by something more invasive, such as a meter with wall probes. This can sometimes be done with no evidence remaining. If the brick is holding water against the sheathing then that would be worth knowing.
Interesting, I was just talking to a colleague about this subject yesterday at the office!! The thing from Wikipedia is very interesting and generally confirms what we had discussed ... if there are weaknesses in the wall, the ivy will find it's way in and through the wall. While there is plenty of ivy covered building examples around, that doesn't mean it is OK. I'd agree that you should seriously consider removing the ivy ... i've seen ivy creep into some construction where I simply don't want it (e.g. under siding, into eave vent screens, destroy window screens, etc.).
The higher than normal moisture on the OPPOSITE wall ... hmmm .... What was 'recording' this? How was this done?
I'm VERY skeptical that he drew a logic line between the two. WOW!!!
First of all, you're in humid Texas ... moisture is always potentially an issue. If there were any such moisture issue due to the ivy, it would likely show up on the same wall.
What is the compass orientation of the wall w/ moisture? Are you maintaining some cooling in the house even though it's empty (I'm assuming it's empty, I guess).
My interpretation
is that the moisture is in the wood framing immediately behind the brick veneer... not across the room.
Good question. The wall opposite that of the ivy is, to me, the one on the other side of the room. Otherwise it's the inside surface of the wall w/ the ivy. Semantics, but that's the difficulty sometimes of expressing/describing in words what we mean.
The ivy would prevent the wall from 'breathing' in terms of getting rid of moisture, so it could easily cause a higher moisture content in the wall behind it. A layer of growth on the exterior of the wall is going to have a tendency to have a much higher level of moisture and it would have a tendency to drive the moisture inward.
So ... OP ... some clarification maybe?
The most likely effect of the ivy would be to reduce the temperature of the wall. This would reduce the tendency for heat to dry out the wall vs other exterior walls.
I'm skeptical that the ivy itself would actually contribute moisture somehow.
Well ... the ivy is 'giving off moisture' and it is retarding air flow across the wall surface. Both will raise the RH near the wall surface and contribute to a higher vapor pressure on the outside vs. inside of the wall. Of course it affects the temperature which affects the moisture issues, too.
i would check the weep holes and make sure they are not blocked
you can get a cheap moisture meter at the box stores for about $30 and take moisture readings and see if your results are the same as the inspectors