why is the framing visible through the wall? this is in LA, so dry climate, and hasn't rained in weeks. the apartment doesn't appear to be air conditioned either. thanks.
chigurh
Jul 16, 15 2:41 pm
moisture in wall, uneven evaporation, framing areas evaporating faster than voids, registering on stucco finish.
Carrera
Jul 16, 15 4:23 pm
^agree, remember also that moisture can come from within living units, it isn’t always rain, in fact most of the flat “roof leaks” I’ve dealt with in my career were interior generated because no one ventilates flat roofs. An average home can generate over 2 gallons of water vapor per day and only needs half of that to maintain comfort, the rest needs to be exhausted or a building will “leak” or sweat. I suspect yours is sweating.
TIQM
Jul 16, 15 5:14 pm
I agree. It is probably not moisture from the inside, though. I've seen this happen just from humidity in the air condensing on the surface of the plaster during the cool night, then evaporating at different rates as the building heats up in the sun.
Carrera
Jul 16, 15 6:53 pm
^ Perhaps, but LA isn’t that humid, tomorrow the humidly will be 56%, know it can get higher but the average is 71%, not high enough to be the sole cause of this. The age of the building keeps me looking at the interior, likely no vapor barrier on the interior walls (or exhaust fans)…guess I would want to get inside first to see where that 365 gallons/year+ of excess vapor is going, then look outside.
Not necessarily disagreeing with anything noted by those above, just throwing another possibility into the mix ... it's just dirt.
If the effect comes and goes with indoor/outdoor temperature changes and interior moisture levels, to me that would point more toward moisture problems. You could get a moisture sensor and take some readings to get a better idea of what is going on.
If the effect is there all the time, including when it gets wet, and there aren't any strange moisture readings or variances between the light and dark areas ... I would suspect it is the ghosting that Parex describes in the link above.
awaiting_deletion
Jul 16, 15 8:59 pm
rob_c your post hints this is recent, but I am going to evaluate it as a condition that has developed over time.
The light lines are most likely wood studs. The color differences disappears as you go down from facade material change, so most likely has nothing to do with interior air, unless the floor plate is where the coloration stops and the two floors are zoned differently with regard to A/C.
The detail between wood siding and stucco is shot or never really existed. Some type of flashing detail should occur there.
The water over time has infiltrated the sheathing. I always get this wrong, but my guess is the vapor barrier is at interior for LA?
The substrate for the stucco has degraded over time due to water infiltration at shoddy detail between wood siding and stucco.
If this just happen, no clue given your comment of no rain.
curtkram
Jul 16, 15 10:29 pm
Vapor barrier should go on the warm side
Maybe it's people causing increased humidity instead of the air? Pack a lot of people tight in a hot room it's sure to have some effect?
mightyaa
Jul 17, 15 10:14 am
Condensation issue; you can essentially tell because the 'wet spots' are in the void areas rather than solids (like studs and floor plates). Basically, dew points and hitting that sweet spot. It's probably further compounded by the watertable band of stucco and siding above. The siding is probably experiencing it too and it's running down into the stucco below. That's part of why it's worse above.
I'm also assuming this is a morning shot and it quickly evaporates as the day gets warmer. I'd also bet it's just a seasonal issue... like morning dew.
proto
Jul 17, 15 1:13 pm
is it a grow room?
Carrera
Jul 17, 15 1:19 pm
^ Think you nailed it:)
JLC-1
Jul 17, 15 2:10 pm
maybe absence of proper flashing between siding and stucco.
no_form
Jul 31, 15 12:11 pm
thanks for the feedback everyone. the condition still exists, about two weeks later now. so after this discussion and the continuity of the problem, i'd say this is long term due to lack of flashing and ability to dry out (not sure why it can't dry out in the LA sun). but none the less, the problem remains.
i'm also curious now carrera how to ventilate a flat roof. typical parapet details that do not have any type of eave or projection for installing a vent do not show a vent stack or something like that, just vapor barriers (which are to prevent rain from coming in).
alternatively, the RH for the grow room is too high, in which case they should burn off some product. hehe
proto
Aug 2, 15 3:57 pm
venting a flat roof? prolly better to have an unvented warm roof but if you can't:
circle vent in wall at ea joist at each end of joist bay
or
"snorkel" vents at each joist bay if there's an intermediate beam blocking cross ventilation
or
create a vented cavity wall at the full perimeter of the parapet w/ a flashing overhang that allows the cavity to breathe
geezertect
Aug 2, 15 8:46 pm
No insulation between the studs, and probably no vapor barrier behind the interior drywall.
why is the framing visible through the wall? this is in LA, so dry climate, and hasn't rained in weeks. the apartment doesn't appear to be air conditioned either. thanks.
moisture in wall, uneven evaporation, framing areas evaporating faster than voids, registering on stucco finish.
^agree, remember also that moisture can come from within living units, it isn’t always rain, in fact most of the flat “roof leaks” I’ve dealt with in my career were interior generated because no one ventilates flat roofs. An average home can generate over 2 gallons of water vapor per day and only needs half of that to maintain comfort, the rest needs to be exhausted or a building will “leak” or sweat. I suspect yours is sweating.
I agree. It is probably not moisture from the inside, though. I've seen this happen just from humidity in the air condensing on the surface of the plaster during the cool night, then evaporating at different rates as the building heats up in the sun.
^ Perhaps, but LA isn’t that humid, tomorrow the humidly will be 56%, know it can get higher but the average is 71%, not high enough to be the sole cause of this. The age of the building keeps me looking at the interior, likely no vapor barrier on the interior walls (or exhaust fans)…guess I would want to get inside first to see where that 365 gallons/year+ of excess vapor is going, then look outside.
Looks like a case of interstitial condensation.
Not necessarily disagreeing with anything noted by those above, just throwing another possibility into the mix ... it's just dirt.
If the effect comes and goes with indoor/outdoor temperature changes and interior moisture levels, to me that would point more toward moisture problems. You could get a moisture sensor and take some readings to get a better idea of what is going on.
If the effect is there all the time, including when it gets wet, and there aren't any strange moisture readings or variances between the light and dark areas ... I would suspect it is the ghosting that Parex describes in the link above.
rob_c your post hints this is recent, but I am going to evaluate it as a condition that has developed over time.
The light lines are most likely wood studs. The color differences disappears as you go down from facade material change, so most likely has nothing to do with interior air, unless the floor plate is where the coloration stops and the two floors are zoned differently with regard to A/C.
The detail between wood siding and stucco is shot or never really existed. Some type of flashing detail should occur there.
The water over time has infiltrated the sheathing. I always get this wrong, but my guess is the vapor barrier is at interior for LA?
The substrate for the stucco has degraded over time due to water infiltration at shoddy detail between wood siding and stucco.
If this just happen, no clue given your comment of no rain.
Vapor barrier should go on the warm side
Maybe it's people causing increased humidity instead of the air? Pack a lot of people tight in a hot room it's sure to have some effect?
Condensation issue; you can essentially tell because the 'wet spots' are in the void areas rather than solids (like studs and floor plates). Basically, dew points and hitting that sweet spot. It's probably further compounded by the watertable band of stucco and siding above. The siding is probably experiencing it too and it's running down into the stucco below. That's part of why it's worse above.
I'm also assuming this is a morning shot and it quickly evaporates as the day gets warmer. I'd also bet it's just a seasonal issue... like morning dew.
is it a grow room?
^ Think you nailed it:)
maybe absence of proper flashing between siding and stucco.
thanks for the feedback everyone. the condition still exists, about two weeks later now. so after this discussion and the continuity of the problem, i'd say this is long term due to lack of flashing and ability to dry out (not sure why it can't dry out in the LA sun). but none the less, the problem remains.
i'm also curious now carrera how to ventilate a flat roof. typical parapet details that do not have any type of eave or projection for installing a vent do not show a vent stack or something like that, just vapor barriers (which are to prevent rain from coming in).
alternatively, the RH for the grow room is too high, in which case they should burn off some product. hehe
venting a flat roof? prolly better to have an unvented warm roof but if you can't:
circle vent in wall at ea joist at each end of joist bay
or
"snorkel" vents at each joist bay if there's an intermediate beam blocking cross ventilation
or
create a vented cavity wall at the full perimeter of the parapet w/ a flashing overhang that allows the cavity to breathe
No insulation between the studs, and probably no vapor barrier behind the interior drywall.