Basement Waterproofing

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  #1  
Old 05-24-19, 11:49 AM
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Basement Waterproofing

Hey guys,

First time poster to the forum looking for some advice on a basement situation. Looking through some of the older posts, I feel like my situation has a little twist that might change the opinions/recommendations on what to do. Ideally looking for a DIY solution to maintain a finished basement.

Background: We just purchased an older home built in the 60's/70's where the foundation is cinder block. To my knowledge, there is no exterior waterproofing done as I see heavy efflorescence in some areas. Currently there is a slight mold problem that came back as being common household molds in addition to a high 75 humidity level during the spring and low 55 during the winter.

Current: Since moving in I've gutted the basement down to the studs exposing the cinder block. Constantly running a smaller dehumidifier which simply cannot keep up with the humidity.

Now the twist...since exposing the walls and moving in, I have not seen any standing water and my sump pump has never gone off or have seen water in my french drain. I actually had a water proofing company come in and say well you don;t have a water problem but you do have a humidity problem.

Question: What would be my best option to water proof and reduce the humidity in my basement? Should I be using DryLok? Would that cause damage to the block considering the moisture trapped in the block itself? Will this last for our lifetime at the house?

I already know that I am going to be buying a heavy duty dehumidifier once we re-hang drywall, but would like to get some fellow DIY'rs opinions on what has worked best for them.

Thanks for the advice in advance!
Eddie
 
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Old 05-24-19, 12:22 PM
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The link is proving to be quite helpful..
https://www.buildingscience.com/docu...ts?full_view=1
 
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Old 05-24-19, 12:45 PM
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If I'm reading this correctly, would the formula be...
  1. Clean wall/efflorescence
  2. Install permeable insulation behind existing studs
  3. Seal insulation with foam
  4. Install fiber glass insulation
  5. Hang dry-wall
Is that accurate for a rigid frame job?

Once that's done buy the biggest dehumidifier I can find
 
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Old 05-24-19, 01:42 PM
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What you're describing is called water mitigation, as you're dealing with it after it has entered the shell of the home. Water proofing is done outside, like with gutters, downspout extensions and grading keeping water away from the foundation in the first place.
 
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Old 05-24-19, 04:12 PM
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Now the twist...since exposing the walls and moving in, I have not seen any standing water
So then the question, was there standing water before tearing out the walls?

Should I be using DryLok? Would that cause damage to the block considering the moisture trapped in the block itself?
As noted waterproofing really needs to be on the outside!
 
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Old 05-25-19, 05:20 AM
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Water Mitigation

thanks @stickshift @marc for the replies

There was no standing water. Everything is dry, everyone that Iíve had come out have been amazed that the sump pump is as dry as it is. It is also severely damaged and dated but no water that Iíve ever seen with heavy rain.

Iíll do some research on water mitigation. Is the idea to construct a barrier between your foundation and dry wall to allow the vapor to enter then trap it before it reaches our finished basement?

Should I be treating the walls with anything other then applying rigid insulation?
 
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Old 05-25-19, 05:29 AM
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Photos

Attaching some examples of the walls and studs.

Is there a way to do this from your phone?
 
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Old 05-25-19, 06:23 AM
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First, moisture issues come in 2 forms, liquid water and moisture vapor. The liquid is obvious as you see wet areas. But moisture vapor is constantly passing through those blocks. The reason it looks dry is it is passing directly to the air. install a barrier and the vapor will accumulate until the exterior side of that barrier is as moist as the source and from your description there is a source.

Efflorescence is a result of the vapor passing directly to the air and depositing the minerals it was carrying.

Installing the rigid foam slows the moisture transport process but still allows some drying to the inside, permeance, it isn't a perfect barrier.

Cinder blocks or concrete blocks have a problem that any water that seeps through can easily flow left or right through those cavities even if they are filled. So any moisture getting into the wll can show up almost anywhere inside.

As a note, DryLok is a water barrier and not a moisture vapor barrier.

If the remaining studs are directly against the foundation they need to be moved away. Regular wood including the bottom plate should not be in contact with the foundation.

We don't have your location so cannot comment on code required insulation levels.

Address the exterior water issues to direct all water away from the foundation.
Dig down a foot or so as I suspect you have a moisture barrier applied to those blocks, usually a black tar type material. It isn't perfect but better than nothing.

Bud
 
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Old 05-25-19, 06:51 AM
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Is the idea to construct a barrier between your foundation and dry wall to allow the vapor to enter then trap it before it reaches our finished basement?
I think Bud touched on everything but since you specifically asked a question about something I said, I will add that you do not want to trap moisture anywhere (which Bud did say); the idea is to keep the soil around the house as dry as possible to prevent water infiltration but, the dryer that soil is, the less vapor will be coming through as well.
 
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