Simon
Jones asked: My father has an old property which is prone
to dampness. There is Ivy growing on some of the outside walls
and he is wondering if the Ivy will dry the walls by 'drinking'
the water out of them or if it would have the opposite affect
in increasing the dampness.
Nick
McLaren is for: That can occur when the mortar is both soft
and not too corrosive (e.g. the older lime mortars) and when the
conditions are such that the wall remains damp for most of the
year. If either condition fails, then ivy will do no harm to brickwork
- it cannot get its roots into modern hard cement mortars, and
will not grow roots into dry mortar. I doubt that it will dry
out damp walls, but that is a guess.
Jon
Rouse is against: Ivy and property don't mix. The roots get
into the mortar, grow thicker and push the bricks out. Whole walls
can collapse when the ivy is eventually removed.
Anton
had a positive experience: This is just a single anecdote,
which doesn't prove the case either way, but a few years ago I
pulled quite a lot of ivy off a bay of my then house (built about
1900, softish mortar). The ivy was moderately recent- I would
guess it had been growing there for 5-10years. There was no damage
at all to the mortar or bricks. apart from some of the little
hairy jobs still clinging to the wall & looking unsightly. I have
to say that I find the idea that growing ivy up a wall might cure
damp a bit unlikely. I suspect free air circulation from naked
walls would be more likely to help.
Martin
came back with : I hope - ivy on house walls won't by definition
damage the walls. Ivy roots will seek out moisture, so if old,
cracked mortar has allowed moisture in, the ivy may exacerbate
the problem.
JennyC
added
that there are several advantages of ivy on walls : It adds an
insulating layer for keeping heat in. It provides accommodation
of birds and wildlife. It actually probably keeps the wall dry
by keeping the rain of. It provides a climbing rack for other
plants to scramble up.
Urban
legend from Jon Rouse: I remember, when I was a child,
a large Victorian house on the main road near us which had ivy
growing up the gable end. They got contractors in to remove the
ivy, and they cut through the main trunks at ground level, and
then pulled the stems down. The whole top of the gable, attic
window, slates and roof timbers, ended up in the front garden.
Yamxs850
wrote: It really depends on the condition of the brick walls.
If they and the mortar are sound, ivy should not cause too many
problems. It will make routine maintenance of the wall (e.g. repointing),
very difficult to achieve, and may mask the presence of early
signs of potential structural failure. If the walls and mortar
are frail, ivy can damage them.
Jack
Russel offered us his experiences with ivy: - Do not grow
ivy on cracked walls, soft bricks etc., walls with soft mortar
types, walls with weak foundations. - Keep ivy under control.
Cut it back one or more times a year, remove shoots growing in
unwanted directions, keep it flat on the wall. Overhanging ivy
can cause a considerable loading. - It is very good for year-round
covering of unsightly walls, for providing shelter to small animals,
for protecting walls against rain. - If removed from a wall it
will leave its footprints which are very hard to remove.
Consensus
of opinion seems to be that :
Sound
brickwork or healthy trees will be fine. Older property's with
old cement might be affected.
