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Old 16-10-2003, 02:21 PM
Bry Bry is offline
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First recorded activity by GardenBanter: Sep 2003
Posts: 51
Default Does ivy harm old houses?

Quote:
Originally posted by Big Bill
Some say when ivy starts getting invasive, in our case invading the
loft by lifting the tiles, it should be chopped at the roots and
killed. Others say that with a 200 year old property like ours, it
should be left alone as it's probably got in so many cracks etc. that
it's contributing in a big way towards keeping the house standing.
Myself, I'd be inclined to leave the ivy to grow along the walls but
cut it back periodically so it stops invading the loft space.
Any thoughts or experiences on the subject please? This is all new to
me. I looked on the gardening forums but there's so many of them I
simply didn't know where to ask.

BB
Well, I have researched ivy on houses as I live in an old 1871 brownstone covered with ivy and was concerned about dammage. The construction is solid brick walls with sandstone cladding over them, which I expect is softer than your bricks. I can't tell you anything about the mortar, except I doubt it's the original 132 year old stuff. In my case the ivy dates back to the late 70's and is very well established with huge thick woody trunks at the base.

When I asked people about the dangers I was told loads of rubish and half truths. One person told me it would get under the foundation and crack it! Another said it leached the lime out of the mortar and made it turn in to dust, which is not true as the little root-things that make ivy cling to the wall don't asorb water or nutrients in to the vine. All the storys I heard are based on the simple illusion whenever someone pulls down ivy they seem to find the wall is a wreck, but when you actually ask them more it's obvious they never looked behind the ivy in years and actually the wall failed naturally while they couldn't see it. And, further misleading still they only removed the ivy when water started to rise up the plaster and cause big ugly stains inside. I doubt we can blame ivy for someone never checking their wall's condition for years (even decades), that would be better classified as home owner ignorance. One person claimed her walls were ruined when the ivy tendrils (her words, not mine!) burrowed in to the mortar. Her evidence being that there wasn't much mortar left and there were ivy stems between the bricks where mortar should be. She wouldn't make much of a detective, it's more obvious the evergreen ivy hid the failing morter for years as it eroded in the rain, and obviously new growth would fill the gaps over time, and of course the reason why this is what happened would be the total lack of mortar chips around the wall.

Ivy is entirely safe on brick/stone houses, but NEVER let it grow on the roof where it can lift slates causing leaks or even cracks. It should also be trimmed away from gutters as it may block them causing damp problems when water spills down the walls. Oh, and do check every year or two behind it to see the general condition of the walls. And finally, don't let it grow over vents for things like dryers and heating appliances.

Bry