Ken's House
Carpenter Ken
answers your questions
Home Questions and Answers How To's Picture Gallery Contact
    
Q. I am renovating two rooms into one family room in our basement. When I removed the wall separating the rooms I found that the floor in one room has about 1 3/4 inches of concrete and tile on top of that. The lower room is 8' x 12' and the higher room is 10' x 12'. What is the best method to level my floor?

A. The first thing I look for in leveling a basement floor is just how out of level is the entire area. Often in an older home, the basement floor is concrete that is sloped toward a floor drain. Even if this is not the case in your home, the basement floor is rarely nice and level. In some cases the entire house has settled and shifted so that the floor above (the basement ceiling) is also out of level. You will have to decide what is important to you; do the ceiling and floor need to be completely level, or just in parallel planes?

To determine how your floor stacks up, use a builder’s level or rotating laser level to mark a level line around the room. Measure down to the floor (and up to the ceiling) to see if this dimension is the same all the way around the room. If it is not, find the highest point (the shortest dimension from your level line to the floor) and plan on bringing the entire floor to this point. Make sure that doing this will not adversely impact doorways and ceiling heights.

To do the actual leveling, you will need to build up the low areas with concrete, mortar or leveling compound. In your case, to raise a large area 1 3/4 inches, I would use a pea gravel concrete mix. You will need to place some temporary screed boards with level tops set to the correct elevation for the final floor height. You can then pour the concrete and use a nice straight 2 x 4 to drag across the tops of the screed boards to bring it to level. After the concrete has set, remove the screed boards and fill the gaps with more concrete or mortar. Before placing any material, make sure the existing concrete is clean and free of paint or old adhesive. Use a bonding agent over the entire area.

Depending on how you will cover the floor… carpet, vinyl, tile or laminate flooring, you may want to use a self-leveling compound over the entire floor after bring it generally to the same height. This type of compound is mixed and poured over the whole floor, and will add another 1/8 or 1/4 inch to the floor’s elevation. If the tile you mention is irregular or loose in places, you may want to remove it before you start the leveling.

 
Back to Questions and Answers Ask Your Own Question
 

Ask CarpenterKen Terms of Use About © 2006 Ken Bryan