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Condensation on vapour barrier

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Feb 08, 2014, 08:01 PM
Condensation on vapour barrier
So I am building a new house. We are roof tight no insulation. Carpenters put vapor barrier and strapping on ceiling. The house is 2200 sq feet with unfinished basement. As a mater of fact just ran a 200,000 btu in the basement to drive any frost out. No problems with foundation and the concrete guy put me 5 weeks behind. Thanks bud. My problem is the vapor barrier has massive condensation on the bottom and is dripping all over the place. Got a drieaz 1700 dehumidifier. It isn't doing squat. The air temperature is 12 degrees. Maybe I have to heat the air up to get the compressor to start pumping. Or I guess the machine says purge. Any ideas?
Feb 08, 2014, 11:09 PM
New construction with lots of exposed raw lumber that still has fairly high moisture content. Add massive amounts of heat, moisture is drawn out of wood but has to go somewhere. Condenses on VB above.

Also unfinished walls could be letting moisture in from outside if outside humidity is high and you are still lacking any of wall insulation, wall sheathing or siding.

It will get better as there is a limited amount of moisture to be removed before it stabilizes around 5% to 7%.

The dehumidifier may not work so well in cold temperatures, but this should not matter if you are able to warm the interior.

This message has been edited. Last edited by: Jaybee,

Feb 09, 2014, 08:38 AM
That's what I figured. A lot of the moisture upstairs is coming from the basement downstairs from running the extreme heat for 15 days. I was unable to get the basement poured due to the guy taking so long putting my 9 foot foundation walls in. He is costing me a small fortune in heat Frown the outside of house is fully covered in 1.5 in r5 rated styrofoam so I guess I will try and maintain warm air downstairs and blast the up stairs with heat. Thanks for your answer. The outside temperature at night has been -25 and -11 daytime Celsius. I think the 200,000 btu should heat upstairs pretty fast. Here's hopping.
Feb 09, 2014, 01:34 PM
Building in Canada in the winter - God love ya. Just a circumstance where there is no way there isn't gong to be complications. Complications always cost money.

On the plus side (for me) is that every time somebody acts as their own contractor in a project like this they never again question why contractors charge so much. Smile

Feb 09, 2014, 05:22 PM
LOL I hear ya. My father is the General contractor. He has saved us a bundle. Even though he used the concrete guy against his better judgement..... long story.Put us behind 4 weeks and into a winter build. We are on budget. Thanks to planning for overages..... still on. The house is coming along great and after I posted this he called to say he got rid of the moisture lol He is not the one worrying all the time it is me lol Thanks for the advice and I guess fathers do know best.
Feb 13, 2014, 06:02 PM
I don't understand why you would build the interior basement walls before pouring the concrete floor.?

We normally use these until the final phases of construction.

Feb 15, 2014, 12:04 AM
It is a construction stage. The outside walls are done. Thanks.
Feb 15, 2014, 03:35 PM
you are also going to get a lot of moisture running the torpedo heater from combustion gases. get it nice and toasty in there and open a window with a slow-speed fan in there.

sig: if this is a new economy, how come they still want my old-fashioned money?
Feb 15, 2014, 10:49 PM
Got it all dried out. Propane off. Used the val6 upstairs nowhere near the moisture the 200000 btu propane put out in basement. Electrical and plumbing time.