Correcting Different Floor Heights

Often in the midst of remodeling some are faced Correcting different floor heights with different sub floor heights that were caused by previous house additions or just plain house settling. The question always remains how to fix and make corrective actions when considering installing hardwood floors through the areas without a transition.

Minor Differences

Typically if the difference is minor, shimming from the low side can take care of the problem. Shims can take the form of different thickness roofing paper or felt. Let’s say we have a situation where a sunroom has been added in previous years and the difference is 5/16 of an inch that spans 20 feet. By installing hardwood over the area in this condition chances are likely the boards may begin to squeak after awhile because of the void underneath.

Adding felt paper parallel to the area can overcome the difference. With standard felt paper measuring 36 inches wide a solution can be adding one layer of heavier #30 felt against the lower area and cutting strips of #15 felt paper while layering and tapering back. For all intent and purposes in this scenario we would have three 20 foot long strips of #15 pound felt cut to widths of 27, 18, and twelve inches or thereabouts.

NOTE: using too many layers of #15 felt can create a spongy effect and should not be considered.

Larger Differences

Any sub floor differences greater should be addressed with different thicknesses of plywood. To fine tune any irregularities, the same method can be added under the plywood. Playing with smaller samples will provide the best idea what is needed.

The Floor Is Lower On Two Different Sides

Here’s a situation that drives many people bananas. By using the example above there are several areas that dip greater than 5/16” Let’s say they are two and three feet wide. Instead of tinkering with more pieces of felt paper that usually ends up creating more problems a simple solution is using sawdust making sure it’s packed down before adding your felt paper.

The example above relates to wood sub floors whereas concrete can be corrected by creating the same tapering effect by way of using a fast drying cementitious based floor leveling compound (photo top of page). This would be necessary if the new hardwood floor were to be glued down. For floating floors both methods can be used. For those that do not want to feel the sloping room effect, plywood can be added to the entire area that sits lower.

Related Pages:

• Floor Leveling On Concrete
• Floor Preparation Wood Subfloors
• Floor Leveling Compound
• Hardwood Flooring Moisture Barriers
• Flooring Underlayment
• Thin Solid Hardwoods - For functionality, price, or tradition