OK, not really falling down, but the plaster is pulling away from the
lath. Here's the story. The house is almost 100 years old. It's
located in Seattle Wa. We have been in the place for 6 years with very
few problems, but in the last few months the walls have developed
large cracks in the lath, all at once. And all over the house. The
thing that has changed recently is that we had the house painted last
fall. I installed vents in the walls so they could breath, but could
expansion in the walls be pushing the lath off the interior walls? My
wife fears that the foundation is settleing and thats causing the
problem. If I call a drywall guy, he will tell me the walls are the
problem, if I call a foundation guy he will tell me the foundation is
the problem. Advice please?
Been there for 100 years and all the sudden problems. First thing
I would be looking at is how good the drainage is around the
foundation. If it hasn't been maintained to a good drainage
grade, water may be pouring down around the footings. Actually
not the footings because it probably doesn't have any. Back then,
18" stone walls were built directly on the (usually) clay dirt.
And yes, I have personally seen that happen.
In a previous post firstname.lastname@example.org wrote...
My guess is that when you installed the vents the moisture content in the
wood changed (for the worse) due to the high humidity of the air --
recently the relative humidity in Seattle was 100%.
This has caused the wood to swell slightly and that has exacerbated
plaster cracking. This can especially true if there is no or very little
insulation. Also, the plaster keys that hold the plaster to the lath were
mostly likely weakly attached (if at all) and the change in moisture
content of the wood was enough to accelerate the cracking.
Finally, the cracks may be due to the Nisqually seismic event of 2001 and
just now showing themselves due to the slight movement of the wood framing
A quick test for settling is to put a ball bearing on a non-carpeted
portion of the floor and see if it rolls toward a low spot.
Bob Morrison, PE, SE
R L Morrison Engineering Co
Also Bob, I think that it could also be the storms that Seattle has had
lately. If any damage was done to the walls, roof with leaks and humidity
was able to get to the interior of the attic/building would cause what you
have mentioned above. Most of those older houses did not have roof
insulation (mine didn't). Also, we don't know if their walls had insulation
either. Mine also didn't. My house was originally built in the 40's only
67 years ago not 100 :-)) The walls with vents and no insulation is a good
estimation for the cracks. The lath was probably wood lath not wire. (
just the way mine is ).
Where are the cracks ? Toward the bottom, top, edges, around doorways.
A picture would be some help I think. Did you do anything to the walls
painting besides the vents?
I would bet the vents that were installed are the problem. Exterior plaster
walls (stucco, right) breath just fine and do not need additional
Moisture behind the walls is a common cause of the problems you are having.
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