Things to Avoid When Finishing Your Basement

Updated on April 7, 2016

Concrete & Wood Contact

The framing for your new finished space is one of the most important components. The new drywall will conform to the framing so it must be plumb, level and straight. So you don't want to use bowed studs that will deform your walls. But the quality requirements don't end there.

Since most basements are inherently moist, you need to keep all untreated wood away from the concrete surfaces. Moisture below the slab can wick up into the concrete and get to the base plates of the wall. Therefore, you need to make certain the bottom plate of the wall is treated lumber.

You also don't want the wall studs to come into contact with the foundation wall. The cool concrete wall causes the humid air in the basement to condense on the surface. This moisture will wick into any lumber that comes into contact with it. So, make sure the framed wall has a gap between it and the foundation wall.

Check out our video at the bottom of the page for frame quality check details when finishing your basement.

Visqueen on Walls

A common question people have when finishing a basement is..."Should I use visqueen or plastic sheeting on one side or the other of the framed basement walls?" The answer is no. Plastic will keep moisture from moving through the wall. As we mentioned earlier, the basement is naturally humid because of it's location below grade. So, moisture can and will get inside the wall. If you use plastic, the moisture will be trapped inside which lead to damage to materials and even mold.

No Insulation at Band Joist

When finishing a basement, we want to make sure the area is properly insulated. Make sure the band joists above the walls have either fiberglass insulation batts or foam insulation covering the entire space. The band joist, sometimes called the rim joist, is the wood framing that runs along the outside perimeter of the first floor framing. We want to make certain this area is properly insulated to keep your new conditioned properly. The photo below shows foam insulation used at the band joist on a finished basement in progress. Foam insulation is preferred over fiberglass as it has a higher R-value, is resistant to moisture and creates better air seal.

Cover Up Basement Wall Cracks

Before starting a basement finishing project, every square inch of the walls should be reviewed for cracks and leaks. Obviously you will want to repair any structural problems with the foundation walls prior to covering them up. You will also want to repair any water leaks. But what about cracks in the wall?

A poured foundation wall crack may or may not go all the way through the wall. Even if the crack does go all the way through the wall, it may still be dry. Newer waterproofing materials are more pliable and will many times span cracks to keep ground water out. Unfortunately, there really is no way to tell if the crack is finished moving.

If a foundation wall crack continues to move and the waterproofing seal on the outside is broken, water can enter. This could be disastrous for a finished basement wall. The leak may go undetected for a period of time which can cause damage to materials and possibly mold.

So, it's always a good practice to repair any foundation cracks prior to covering the walls up.

Building a New Home with a Finished Basement

So if you're building a new home there are some items to incorporate into the foundation that will make for a better finished lower level.

  1. Install visqueen under the complete basement slab and tape the joints
  2. Consider adding insulation to the outside of the basement wall - this can serve as protection for your waterproofing also
  3. Waterproof the outside of the foundation wall...don't just use the code minimum damproofing
  4. Consider installing an interior and exterior drain tile connected every eight feet through the footer...this will add redundancy to your drainage system
  5. Add a battery backup to your sump pump
  6. Us the best sump pump you can find (Zoeller makes a good pump)


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