I got a call from a client who I built an 3 season (currently unheated) sun porch addition for claiming he was getting either a leak or sweating on the cieling. He says the problem is more pronounced now that days are cooler to the point where there are small puddles gathering on the floor. He also says there is not a problem when it rains.
The room was built into an inside corner “L” so that two brick walls hold up the ledger for the flat roof rafters and the other two walls are free standing wood framed.The brick walls were left exposed. Also a concrete slab floor with porcelain tile and epoxy grout.
The room has Marvin windows ganged along the outside walls and faces south so it warms up pretty well during the day. The soffit has continuous perforated aluminum and I drilled a series of holes through the rafters to increase airflow. I know its not an ideal ventilation plan.
The roof is a very slow pitch with a continuous patchwork copper finish. the copper bends upward on the brick and also becomes the counter flashing. I dont think this is a leak.
The owner told me he never had the brick sealed. I suspect capillary action is wicking moisture past the roof assembly and the two interior brick walls are the source of moisture that is condensing on the underside of the cieling.
I am thinking of soldering a few static vents to the copper roof along the brick walls to increase ventilation. Also I want to open some weep holes above the counterflash and below the soffit of the main house to increase air flow behind the brick.
Also I think the brick should be sealed and maybe the brick walls inside the addition should be thoro-sealed and painted.
All comments would be appreciated
Replies
Is there a moisture barrier under the slab?
Unless you're the lead dog, the view just never changes.
Yes , a double layer of 6 mil plastic. I dont think the slab is the problem having porcelain tile and epoxy grout. that combination should be barrier enough
I realize you said it's unheated.
No unvented gas fireplace or kerosene heater right?
Humidity is coming from somewhere. Brick might just be the cause.