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Need help with moisture/vapor barriers on above grade basement

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  • Need help with moisture/vapor barriers on above grade basement

    Hello,

    My money pit threw a real curveball at me...

    House is a "raised ranch" (late 60's split level) with the first floor on-grade. We are on the side of a hill and have some runoff issues that cause springtime ground water levels to be fairly high, and we live in a very humid microclimate in the summer in centeral NJ. We've been in the house 1 year and we're in the process of refinishing the garage and first floor ceiling after replacing the entire HVAC system due to an undersized ductwork problem and issues with the electrical. We gutted the ceilings and replaced everything, and gutted the entire garage (which is under the living space), insulated with spray foam, and are in the process of replacing the wallboard.

    Problem we hit is that there has been a musty smell in the basement, which I was hoping would go away with the HVAC fix and a newly airtight garage. It didn't and when vacuuming I hit the floor molding and a huge hole popped in the molding... it was rotted clean through. The drywall was damp and weak... spongy. I wound up ripping out that one wall since I'm already knee deep in wallboard.

    I found that there were studs on the concrete foundation, which goes up about 3 feet from grade, with unfaced insulation and 6mil poly vapor barrier under the drywall. The vapor barrier was on the drywall side, holding the insulation between the barrier and the concrete block. Well, there was obviously a long standing problem with moisture trapped in this space, as the wood studs were all completely rotted out. I pulled them out in handfulls of rot. Behind the vapor barrier it was damp, so was the insulation. Not so much mold on the insulation, and a small amount of mold on the drywall, it looks like condensation dripped down the vapor barrier, accumulated on the wood, and wicked into the drywall. The mold was limited to about 2" on the back of the drywall, whereas the sponginess went up about 2 feet.

    SO how do I fix this? I am thinking of DryLoc or some other heavy solid watersealing on the concrete, and then putting metal studs and poystyrene foam panels as insulation, and then putting up the green mold-resistant drywall on those studs. My second inclination is to skip the dryloc and the insulation and simply do metal studs and drywall (green).

    I read highly conflicting advice on which side to put a vapor barrier on so I'm inclined to use foamboard if I do use any insulation... would it work well with dryloc or would the two combined cause moisture problems? Should I just let it air and use nothing?

    Pics attached.

    Any advice?
    Last edited by Ih8moneypit$; 08-18-2011, 11:14 PM.

  • #2
    While it might appear daunting, your not alone in what your experiencing, this problem is common and solvable.

    How deep is the outside grade to the bottom of the basement wall on the uphill side ? Does the grade fall "to" the home ?

    Depending on the answers to the above questions an ideal fix would be to install a perimeter drain around the exterior (or uphill side) draining to daylight/street/downhill etc...Of course if the grade falls towards the home and it's surface water causing the issues then a simple re grading to direct surface water away will go a long way to solving the issue.
    Metal studs are an option but if your looking to save money (electrical wire must be protected when run through metal studs etc...) use treated lumber, code dictates that any lumber in direct contact with concrete/bricks etc... must be treated material for exactly the reasons your seeing. you could use just a treated bottom plate.

    Is this room heated and cooled ?
    Little about a lot and a lot about a little.
    Every day is a learning day.

    Comment


    • #3
      The grade is at the floor level, on the other side of that wall is a paver patio. The hill is about 6' and does an 8% grade to the patio, the patio is 15' with about 1' graded away from the house. The hill has a trench drain that is inadequate depth for the grade; we are planning on doing a retaining wall on the hill with double 2'-3' drains (one front, one back of wall, to get deeper than the footings).

      Additionally I am looking at new gutters, the soffit over the patio is only 1 1/2' deep and I've only got a 4" gutter, the roofline is over 70 feet continuous and I probably need a 6" gutter to handle the volume of water generated in a good summer thunderstorm. In a t-storm the water cascades over the gutters and splashes onto the house. All gutters drain underground to the street and are clean.

      The first floor is fully heated and cooled and we replaced the ductwork in the entire house as the airflow was 1/4 of what the new high efficiency hvac installed by the previous owners required.

      All electrical runs through the wood framing, the concrete only goes up 3' and then there is framing. The damage we found was to a faux wall that somebody put up apparently in a remodel.... The sill plate on the cinder block is undamaged and pressure treated, while the bottom plate was obviously not.

      We are clearly going to need to deal with the outside water, but that's a next year project due to costs, fixing the hvac has blown the house fund for this year. Will probably do gutters this year.

      So what's the best plan to put the wall back together with the recognition that I will have to deal with the outside by next summer when this cycle starts up again?

      Comment


      • #4
        So the faux wall was in front of the 3' high concrete wall ?

        Before you rip off your gutters, 4" gutters should be wide enough to accommodate almost all water flows, there are usually a couple of issues that usually result in overflows like you describe.
        1. Not enough downspouts to take the volume, Bigger downspouts will also help alleviate this problem if you cannot increase the number of downspouts.
        2. Roof deck overhangs too far (high volume of water flow overshoots the gutter)
        The roof deck should be no further than at the max. halfway across the gutter.


        When you say the water cascades over the gutter, is the gutter full and overflowing (need more downspouts), or is the water racing over the gutter in heavy rain ?

        I'd hate to see you remove the gutter and replace it if a cheap fix of downspouts is the solution.

        The water issue should be resolved before any rebuilding happens.
        Little about a lot and a lot about a little.
        Every day is a learning day.

        Comment


        • #5
          The faux wall is both on top of and in front of the 3' concrete wall... They put 2x4s laid flat on the lower portion down to the floor, and framed proper 2x4s on top of the sill in front of the real finished walls.

          So above the cinder block there is wallboard, 2x4 framing, wallboard, then 2x4 framing again, then exterior plywood and cedar shake shingles. below, it's wallboard, 6mil poly vapor barrier, 2x4framing done the wrong way, then cinder block to exterior with the exterior painted.

          The gutters have been on the to do list since winter, we suffered a lot of ice damming with the record snowfalls in the mid-atlantic. The rain flows over the gutter as though they are full. Downspouts are every 30 feet. Gutter guy came out today and suggested we leave the front of the house as is, but in the back where there is damage replace with a 6" gutter, and gutter guard the whole house. Increasing all the downspouts to 3" as well.

          But this damage clearly did not come from one season of bad gutters, the framing on the masonry was rotted straight through to dust... This has been a long standing issue. I think the is a lot of condensation behind that vapor barrier.

          Comment


          • #6
            Since your going to replace the rear gutters anyway I still say "wait" until at least you have replaced these gutters, if you knew how many jobs I've been on where clients "thought" they had solved a problem with water only to have me pull out more work they had done.

            On rebuilding the wall, if it were me I'd be using treated lumber 2x6, notch out the lower section of the 2x6 so the front edge runs down to the floor. This way you have your 2x6 sitting on the wall and running down to the bottom plate(treated as well), Use sill seal foam to seal the bottom plate to sill and the concrete slab, (blue on a roll). R13 insulation is the min. code for walls and should be faced (faced side toward the heated area) it's probably your best option as long as you can keep the contact between block wall and insulation to a bare min. If you have some extra money definitely go for spray foam this is without a doubt your best option.
            Little about a lot and a lot about a little.
            Every day is a learning day.

            Comment


            • #7
              Thanks for the tips.... So what are your thoughts on dryloc on the concrete before finishing?

              Comment


              • #8
                You could add the dryloc as another step of prevention, I'm not a huge fan of dryloc, it's mainly used as an interior application which means your trying to stop the moisture after it's soaked the wall/blocks.
                Your wall is above grade so it shouldn't be subject to constant wet soil etc...
                Application to the exterior side would be far more effective, you can have it tinted to a color, problem here is your then into painting brick and some don't like doing that.
                Even a coat of standard exterior paint on the exterior side (above grade) acts as an effective moisture deterrent for moisture issues involving splashing water etc...

                There is also a product called Quik-wall (lowes/HD etc in the bagged cement and mortar isle) that is a Portland cement based product mixed with fiber, you mix it up like mortar and apply it like stucco over the wall, trowel it out to your desired finish, let it dry and paint if required. It's used to hold un mortared block walls together as well as coating the inside of ponds and fountains as a effective water sealant.
                Little about a lot and a lot about a little.
                Every day is a learning day.

                Comment


                • #9
                  reply

                  Arizona Polymer Flooring makes a vapor barrier that is painted on the floors and dries clear. It is a vary good product used in commercial buidings.

                  Comment


                  • #10
                    I don't know

                    the original poster started this thread in august of last year. I doubt he/she has any more interest in the posting or the answers. you're answering a post longer than a year ago. you want to delete your messages?

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