Basement – Humidity levels in new basement are high

basementhumiditymoldvapor-barrier

I'm currently living in a new build in Ottawa Ontario for which I took possession in February 2020 ( I've been here for about 5 months ). The humidity levels in my basement have gone gangbusters in the past couple of months. I currently have 2 dehumidifiers running full throttle 24/7 to keep the RH at around 50%.

Without these machines running I've seen the RH climb up to the mid 70s.

I thought I had it under control, until I saw water inside the vapour barrier.

The builder told me it was because the cement isn't completely cured yet… Is this true? My understanding was that cement took around 30 days to cure.

Note that the landscaping isn't done yet, so the grading isn't right and we don't have any eavestroughing as of yet.

Should I be concerned about mold? I feel like they are pulling on fast one on me…
I had plans to finish the basement ( Seal the floors, put up drywall etc).
Any advice?

Thanks!

Water droplets behind the vapour barrier

Best Answer

Your home has been in this state for 6 months. There should not be any extra moisture that needs removing after this length of time. And 6 months is more than long enough to start getting lots of mold and water damage behind that vapor barrier.

The purpose of that vapour barrier is to prevent moisture from inside the home getting into the insulation. There should not be water on the outside portion of it!

I don't know your local building codes, but in our area of the country (SK), they require sealant on the exterior walls, weeping tile and sump, proper grading. I don't believe that eavestrough are required.

  • Contact your city's building inspector. Let them know you have a new build, that you can see water inside the moisture barrier in the basement, and the builder says its normal. Request that they come look at your new build home, request what the builder planned for sealing the basement.
  • Document what you are seeing and doing about the moisture. You want lots of pictures, dates. Record the approximate amount of water you get out of your dehumidifiers.
  • Contact your insurance company. They may be willing to go after the builder as well, because they will be the ones on the hook for damages if your are covered.

I don't want to sound negative, but you are probably going to end up fighting your builder over this. They are either incompetent, or malicious. A newly built home should have proper drainage and sealing on the outside of the basement walls to prevent this. Your new home warranty only lasts for a certain amount of time. Get the ball rolling ASAP.

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