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Construction moisture & underfloor heating
Hello
I am in the process of extending my house and have encountered some issues that I wonder if anyone can help me with. I'm building with a slab on grade and the slab was poured at the end of September last year. As I'm building myself, it’s going quite slowly. The roof and walls went up in November and on a cold day in early January, I installed the windows. Once the windows were in place, I started heating the whole house with a construction heater, and last week I connected the underfloor heating. Throughout the process, I've been careful not to trap any moisture, and I believe I've succeeded in that. The problem I see now is that after switching on the underfloor heating, I notice that it's a bit damp in some places at the bottom of the walls. What do you think this is coming from? Is it moisture from the slab that is being released now that the heat is on? Could it be moisture from the studs coming out when the heat starts? Any other ideas? There has also been a significant weather change today. Until yesterday, it was steadily below -5 for a long time, and today it suddenly reached a few degrees above zero.
I am in the process of extending my house and have encountered some issues that I wonder if anyone can help me with. I'm building with a slab on grade and the slab was poured at the end of September last year. As I'm building myself, it’s going quite slowly. The roof and walls went up in November and on a cold day in early January, I installed the windows. Once the windows were in place, I started heating the whole house with a construction heater, and last week I connected the underfloor heating. Throughout the process, I've been careful not to trap any moisture, and I believe I've succeeded in that. The problem I see now is that after switching on the underfloor heating, I notice that it's a bit damp in some places at the bottom of the walls. What do you think this is coming from? Is it moisture from the slab that is being released now that the heat is on? Could it be moisture from the studs coming out when the heat starts? Any other ideas? There has also been a significant weather change today. Until yesterday, it was steadily below -5 for a long time, and today it suddenly reached a few degrees above zero.
I have opened into the existing house, so the ventilation is connected to the mechanical exhaust ventilation. However, I don't have a separate "construction ventilation" right now. I don't have a moisture meter for wood but a hygrometer that's there, and it shows 42%.ordain said:
When I saw the moisture at the bottom, I took apart a bit (I haven't plastered yet) to see if I could find the source. When I put my hand into the wall, it feels like there is a bit of frost on the inside of the wind barrier. The walls consist of plasterboard-chipboard-vapor barrier-145mm standing insulation-45mm lying insulation-wind barrier-air gap-panel.
My own theory is that it's moisture from the slab/construction material that comes out when I turned on the heat, which then forms frost on the inside of the wind barrier. When the weather became milder, the frost melts, and it becomes moisture in the wall. Could that be correct, and if so, it should disappear as soon as I manage to ventilate away all the moisture, right? What do you think about turning the floor heating up to max to get rid of the moisture?
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