ᐅ Heating the House During the Construction Phase?

Hello everyone,

We are now in the interior finishing phase, meaning the remaining openings will be closed soon. After that, the screed is scheduled for early December. The interior plaster has fully dried after 12 weeks. It is getting colder now, and inside the house it is still 1-2 degrees Celsius (1.8-3.6 degrees Fahrenheit) cooler than outside because the vapor barrier and insulation on the upper floor are not completely sealed yet. According to the site manager, it doesn’t make sense to set up a small heater, although the construction power supply is running through the general contractor 😀. Therefore, the question is: does it make sense to heat a bit with a 2 kW heater? Thank you very much.

If underfloor heating is installed, the pipes should be laid before the screed is poured, and heating (as well as ventilation) is necessary during the drying process anyway. By that time at the latest, the vapor barrier for the roof insulation should be sealed, otherwise it will get damaged.

I don’t understand why it would be cooler inside than outside just because the roof insulation is not finished yet. I only know that it gets colder at night than outside.

Otherwise, as long as it is frost-free or nearly frost-free (a slight ground frost in the morning), this is not really necessary, especially if no work involving wet materials (plaster, adhesive, screed, etc.) is being done inside.

Was the relative humidity ever measured on the upper floor? I would simply place a small dehumidifier there with a drain hose. The waste heat from it would be enough to serve as a ‘heater’.

I haven’t measured the relative humidity yet. I was on site every day, and especially on the mild days around +15°C (59°F), I kept the windows open almost all day. The underfloor heating will, of course, be installed before the screed and will also be used to help dry the screed. I plan to set up one or two fans inside the house to promote air circulation and, of course, ventilate frequently. For now, before the underfloor heating is running, I’m wondering if additional heating makes sense to help closed openings dry faster, for example.

I’m facing the same issue, although in my case the screed has already been laid for 8 weeks.
I consulted several "experts" independently, including the construction manager, the building technician from the developer, the plumber, and a master mason...

They all advised me not to let the house "freeze," but rather to install a small heater—one per floor.
The costs are manageable. If you keep the temperature above 5°C (41°F), you might need around 1,000–2,000 kWh over the winter. Even at $0.50/kWh (usually it’s only $0.30/kWh until January 1), that’s $500–1,000.

If the screed has just been laid, you have to heat anyway, right? As I understand it, it will not cure properly below 0°C (32°F). You’re also not supposed to pour concrete during frost.

xMisterDx schrieb:

I’m facing the same problem, although the screed has already been laid for 8 weeks.
I asked several experts independently—site managers, construction technicians from the developer, the plumber, a master bricklayer...

They all advised not to let the house cool down too much, but to put in small heaters, one per floor.
The costs are manageable. If you heat above 5°C (41°F), you might need around 1,000-2,000 kWh over the winter? Even at $0.50/kWh (usually until January 1st you pay "only" about $0.30), that’s around $500-$1,000.

If the screed is freshly laid, you have to heat anyway. As I understand, it won’t cure below 0°C (32°F). You’re also not supposed to pour concrete in freezing temperatures.

Yes, use a construction dryer.
It removes moisture and with the waste heat from the 800W unit, you have your heating.
You can also buy two inexpensive basement dehumidifiers with 400W each, but you usually have to empty the water tanks manually.