Dealing with uneven floors is a common issue in old houses. Uneven floors can make furniture wobble, cause people to trip, and just look unsightly. However, there are several effective methods to fix uneven wood or concrete floors in an old house.
Evaluating the Floors
The first step is to thoroughly examine the floors to determine the cause of the unevenness. Here are some things to look for:
- Check if the floors sag in the middle of a room or dip near walls and doorways. This indicates the floor joists may be loose, warped, or damaged.
- See if certain boards are higher or lower than others. Individual loose boards can create an uneven surface.
- Look for gaps between boards that indicate possible water damage or rotting.
- Determine if unevenness is limited to one area or affects the entire floor. This helps pinpoint the underlying issue.
- For concrete floors, check for cracks, crumbling edges, holes, and raised or sunk sections.
Once you’ve identified the specific problems, you can choose the best method to fix them.
Refastening Loose Floorboards
If you have uneven wood floors due to individual loose boards, you can often correct this by refastening the boards to the subfloor and joists. Here’s how:
- Use a pry bar to gently lift the problem boards just enough to slide shims underneath. This will support the boards at their proper height as you work.
- Check for decayed or broken edges on the board and sand or cut away any damaged sections.
- Re-secure the board with new deck screws driven into the floor joists. Predrill holes to prevent splitting the wood.
- Use an appropriate wood filler, like putty, to patch any gaps or holes. Let dry completely.
- Sand down the repaired boards flush with the surrounding floor. Refinish as needed.
Properly re-securing loose boards can eliminate uneven spots and squeaks.
Sanding or Planing High Spots
If you have isolated high spots or boards that are elevating sections of floor, you may be able to sand or plane them level with the surrounding floor.
- Mark any severely raised boards with painter’s tape or chalk. Measure the height difference.
- Use a belt sander or hand planer to gradually remove height from the raised boards. Check frequently with a level or straightedge.
- Be careful not to over-sand low spots in the floor, as this will thin the boards. The goal is to meet in the middle.
- Vacuum up all dust thoroughly when done sanding. You may need to refinish the sanded boards to blend with unsanded sections.
This technique works best for minor uneven spots under 1/4 inch high. It takes some skill to sand perfectly level without thinning flooring too much.
Sistering Floor Joists
Sagging floors are often caused by weakened or damaged floor joists. Sistering involves securing new joists alongside existing ones to reinforce support.
- Gain access to the floor framing from below and inspect joist size, span, and spacing. Identify any cracked, warped, or deteriorating joists.
- Measure existing joists and get equal sized new sister joists. Pressure treated lumber works well.
- Bolt or screw new joists tightly against old joists at regular intervals. Stagger fasteners to balance strength.
- Check that new joists extend the full span and are supported correctly. Shim any gaps behind or under joists as needed.
- With joists sistered, floors above should become stronger and more level over time. May require refinishing.
Sistering is an efficient method to strengthen floors without having to replace large sections of subfloor or joists.
Filling Low Spots
Another approach for fixing uneven wood or concrete floors is to build up and level any sunk sections. Some good fillers include:
- Self-leveling compound – Pourable resin compound spreads evenly. Just pour over low spots, allowing it to settle. Easy for DIYers to apply.
- Patching compound – Available at hardware stores, this can be troweled on and smoothed over dips. May require priming first.
- Latex concrete – For concrete floors, mixes with water and can patch minor holes or depressions. Sands smooth when cured.
- Epoxy patches – Two-part epoxy can be mixed and poured to fill concrete cracks and pits flush with the floor.
Be sure to thoroughly clean and prep the floor prior to applying any patching compound. Follow manufacturer’s instructions for drying time. Sand and finish patched areas to blend with the existing floor. Filling low spots can effectively make floors flat again.
Replacing Damaged Subfloor Sections
Extensive water damage, dry rot, or broken joists may require replacing sections of subfloor in especially uneven areas. This involves:
- Marking out the damaged subfloor area to be replaced. Cut to the center of floor joists with a circular saw.
- Lifting out the old subfloor with a pry bar, hammer, and/or reciprocating saw.
- Measuring and cutting replacement subfloor panels to fit tightly. Glue and screw into place.
- Sanding replaced section flush when dry. May need to refinish surrounding floor.
While labor intensive, subfloor replacement is sometimes necessary for structural integrity and an even finished floor. Be sure to address underlying moisture issues that can cause damage.
Installing a New Surface Floor
If uneven floors are beyond simple fixes or affect the entire floor, consider covering over the old floor with a new surface layer. Options include:
- Plywood – Gluing and screwing new plywood over high and low spots essentially creates a fresh, flat subfloor.
- Vinyl – Flexible vinyl flooring adheres well over uneven floors and provides a seamless look.
- Laminate – Floating laminate floors can form to minor irregularities while offering durability.
- Ceramic tile – Tile installed with a mortar bed works on uneven concrete after high points are ground down.
- Carpet – Carpet and padding can mask minor uneven areas, just avoid excessively thick padding.
Carefully prepare the original floor and choose an appropriate material that works with the level of unevenness present. This may be the best solution for extensively damaged old floors.
Preventing Future Unevenness
Once your floors are smooth and level, be sure to maintain them properly to prevent recurrence of problems:
- Keep moisture under control to avoid warping boards or deterioration over time.
- Add supplemental joists or support posts underneath to reinforce weak spots.
- Refasten any loose boards or sections that develop. Fill small gaps.
- Consider recoating or refinishing floors every few years to protect from wear.
- Have floors professionally evaluated if you notice new cracks or changes in levelness.
Addressing uneven floors promptly and keeping them maintained will help ensure your historic home’s floors stay strong and flat for decades to come. Don’t hesitate to contact a contractor for guidance on the best solution for your specific flooring issues. With some patience and the right approach, you can smooth out the rough spots.
Frequently Asked Questions About Fixing Uneven Floors in Old Houses
What causes uneven floors in old houses?
Some common causes include worn and loose floorboards, deteriorated or warped joists, foundation settling, moisture damage, and improper original construction. Old flooring naturally shifts over time as houses settle.
Should I tear up old subfloors to fix unevenness?
Removing subfloors is usually only needed if there is severe damage or sagging. For minor dips or loose boards, less invasive fixing methods often suffice. But if the subfloor itself is compromised, replacement may be required.
How do I tell if my floor joists need repair?
Signs of weak joists include noticeable sagging between joists, severe springiness, cracked or warped framing, and separation between joists and subfloor. Sistering may be needed to strengthen extensive joist damage.
Is refinishing enough to make old floors level?
Sanding and refinishing can help smooth out minor high spots but does not address low spots or structural issues. Refinishing provides a fresh surface but does not flatten fundamentally uneven floors.
Should I use self-leveling compound on old wood floors?
Self-leveling products are best suited for concrete subfloors. For wood floors, trowelable wood filler specifically designed for floor patching often works better to fill depressions flush.
Conclusion
Revitalizing uneven hardwood or concrete floors in an old home takes patience and the right solution for the specific issue at hand. Addressing sagging joists, refastening loose boards, sanding high spots, and filling depressions can often restore levelness. For whole-floor fixes, installing new plywood or a surface floor provides a fresh start. With diligent troubleshooting and care, historic homes can maintain their charm while offering smooth floors for years to come.