# Framing basement over interior French Drain



## soparklion11 (May 15, 2017)

I own a 1940s home with a basement.  The walls in some areas of the basement were bowing, which is common here in western Pennsylvania due to wet soil and collapse of the terra cota exterior footer drainpipe.  SO we all get interior french drains...

I want to furnish the basement again by framing, hanging drywall and placing an engineered wood floor.

I now have an interior french drain with only a few inches of concrete over the drain trough.  The drain was installed 2.5 years ago and there has never been water in the sump.  There is a plastic vapor barrier against the wall.  The concrete had been painted in the past but much of that pain is no longer present.  The floor is a very smooth concrete, with no cracks, no flaking, and no evidence of moisture.

I plan to frame out the basement by using a treated 2x4 for a sill piece and to secure it using liquid nails, then build to the rafter.  1. Should I use a concrete sealer under the sill?  2. Should I use concrete sealer on the entire floor? 3. Should I use a sealer or a dryloc-type paint product?


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## nealtw (May 15, 2017)

Put a sill gasket under the bottom plate so wood does not touch the concrete.
Use 2 inch concrete nails to anchor the wall, they go in 1/4" or less and are enough to stop the wall from moving.
They work best if you build the wall first, fairly tight to the ceiling so nothing moves when you nail it down.
We build then 1" away from the wall so any bumps in the concrete do do not cause a problem.
The space at to behind the wall should be fire stopped which we do by adding lumber again the sill plate above the concrete and then the top plate and level down to the floor.
If your drain is working well a seal should not be need by may be a subject for discussion.


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## Sparky617 (May 15, 2017)

Use a pressure treated sill plate.


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## nealtw (May 15, 2017)

Sparky617 said:


> Use a pressure treated sill plate.



A couple points. The sill gasket separates wood from concrete.

Normal treated lumber needs to be in a place where it will air dry after getting wet. So underground rated would be what to use.
You do not want to use underground rated in the house.:2cents:


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## Snoonyb (May 15, 2017)

Or, you could use 1-5/8" steel studs that do not twist or bow, and save you 2" of lost space.


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## soparklion11 (May 16, 2017)

Thank you all!  The cement block foundation walls were bowing inward and Carbon fiber straps were placed to stop the inward movement.  However, they now just establish a limit to how far that the cement block walls can bow... meaning that at times the walls straighten and the carbon fiber straps 'slack' and gap away from the wall... about 4-5 inches loses contact with the wall and is just about an inch away from the wall. My framed wall will not touch the foundation wall that bows.  

*Is it necessary to build a floating wall so that when the foundation wall bows the drywall doesn't crack?*  Floating walls aren't code in my area.

*Can I stack the following - Cement : Construction adhesive : Barrier : Adhesive : Treated 2x4 Sill?*  Then add a few concrete anchors?


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## nealtw (May 16, 2017)

The float wall is used when you expect the floor to float up, more often it is when you expect the floor to move do to frost below.
If you have a pump failure or a high water below the floor, it will more often leak than float.
We have gone the other way when a wall is suspect and we thing the footing is just below the floor, will build the wall as a bearing wall that would apply the weight to the floor and footing
Did they not do anything to relieve the pressure on the wall? I have seen holes bored down to the depth of the foundation and filled with gravel to help water move down to the drain on the inside.

And for those that are thinking what is a floating wall.
[ame]https://www.youtube.com/watch?v=NqhH3pAGGHg[/ame]


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## soparklion11 (May 16, 2017)

Nothing was done on the outside of the house.  There has never been free water in the basement and the landscape slopes away from the house in all directions...  Thank you for the quick response!


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## nealtw (May 16, 2017)

soparklion11 said:


> *Can I stack the following - Cement : Construction adhesive : Barrier : Adhesive : Treated 2x4 Sill?*  Then add a few concrete anchors?



If you believe the glue will not be food for mold. The idea is to not let wood touch concrete so it the glue separates the two, I guess so.
But it won't be normal construction glue it will want to be something for concrete.


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