Wood or carpeted floors often make creaking or crackling type sounds when walked on. There are four main reasons for this.
Temperature & Humidity Issues
Improper Installation or Workmanship
Settling & Foundation Movement
1. Subfloor Causes
Carpeted floors with a wooden subfloor
When walking across a carpeted floor and you hear a creaking sound, it is usually from one of the following reasons and can usually be corrected easily.
The sub floor, which may be constructed of plywood, wood planks or boards, OSB Board or particle board, laid over floor joist which supports the plywood or other sheeting.
Floor joist tops not level
If the tops of the floor joist are not flat and level, then the sheets of plywood or sub-flooring will not be fully supported evenly. When nailed down, the sub-flooring will be sucked down unevenly. Over time the portions of the floor that have been sucked down will try to go back to a flat and level position. When this happens a gap will develop and the nails holding the floor will be pulled loose slightly.
Now, when this area is stepped on, it will flex downward (because the nail has pulled loose), then back up; this creates a creaking sound.
Floor joist damaged, cracked or not blocked
Should a floor joist be cracked or damage, then the nails holding the sheeting may work loose; thus the creaking sound.
Generally floor joist are blocked every so many feet to help hold them in place and from moving. If this blocking is not properly placed or missing, then this may allow the joist to move. Should this be the case, homes with a crawl space, will usually allow access to the joist area and repairs or blocking can be easily made to the floor joists.
Occasionally, if the floor joist are spaced two far apart to properly support the sheeting, then floor creaking may occur. Rarely is this the case.
The majority of sub flooring issues can be corrected by adding screws in the areas where the creaking is occurring. Screws will normally do a much better job of holding the subflooring down and will not work loose.
Tip for buyers – if you’re going to add new carpeting.
Before you sign the contract for the new carpeting, ask the sales person or contractor if they will take a few minutes and screw down any loose subfloor sheets before they put the new carpeting down. Request that this be part of the agreement, for if you wait until the installers are putting the carpet down, they may claim that it was not part of the contract and want several hundred dollars more to do it. Where in reality, it only takes them a short period of time and a couple of dollars in screws.
2. Temperature and Humidity Causes
When wood boards or planks dry out, they shrink. When they shrink, a thin gap or space occurs between the boards. Then when walked upon, the wood pieces rub against one another and you hear a creaking sound.
Winter and summer months
Hardwood floors will usually shrink in the winter months and expand in the summer months. Also, sudden temperature or moisture / humidity changes will affect expansion and contraction changes. This expansion and contraction can result in the flooring coming loose from the subfloor. Glued floors come loose or the nails pull loose. This will cause creaking in the floors.
When this occurs you may want to re-attach or secure the floor back down and apply a sealing compound to the flooring which helps prevent this type of problem.
Engineered wood floors v. Solid wood floors
Solid wood floors are more affected by temperature and weather, than engineered wood floors. Engineered wood flooring take into consideration temperature and humidity types of conditions and therefore designed their flooring to resist these types of issues.
Lubricate Tip for Old Solid Oak Flooring
Sprinkling a little talcum powdered or powdered graphite in joint or nail areas where the boards are creaking may help reduce the creaking noise. Once sprinkled, then stepping on these areas a number of times helps work the powdered into the voids or cracks. Be sure not to track the powdered around and clean up the surface after completion. It may require the lubrication process sever times before noticeable results occur.
3. Improper Installation & Poor Workmanship
Nail guns and glues
Subfloors are usually secured down to floor joist with nails and often glues. One common practice is to run a bead of glue along the top of the floor joist, then lay the plywood or other floor sheeting on this bead of glue – then nail the sheeting into place.
Workmen may not get the sheeting laid on top of the freshly placed glue bead quick enough and the glue begins to set; resulting in a poorly secured piece of sheeting.
When the carpenter comes along to nail the sheeting in place, he usually uses an automatic nail gun. He uses the nail gun to shoot nails into the sheeting to secure it to the top of the floor joist. The problem with this type of work, is that the nail gun operator is usually in a hurry and just goes pop / pop / pop with the gun. This fast pace nailing results in nails missing the floor joist under the sheeting. Thus, these nails are ineffective. Believe it or not; many nails miss their mark.
Both of the described practices are an example of poor workmanship.
Not following the manufactures recommended instructions on nailing, spacing and installation is another key reason for creaking floors.
If the subfloor is poorly installed, not level, has bumps, damage or imperfections, then creaking may occur.
Manufactures will often recommend that their flooring acclimate to the environment that it will be placed in. Failure to do so may result in bowing, cupping and excessive expansion or shrinkage may result.
It’s important that the manufactures recommendations be followed. Many DIY ignore these recommendations and even professionals will when they’re in a hurry.
4. Settling and Foundation Movement
Over time a home may experience some settling or the foundation may shift or move due to expansive soils or other soil related movement issues.
When the foundation moves, shifts or settles, then there may be stress or limited movement of the flooring support or sub flooring. Thus, the floor may start creaking because the wood sections or pieces of the flooring are rubbing together, damaged or the nails have pulled loose. If there has been significant differential settlement there is more of a likely-hood of damage to sub-floors and creaking to occur. (Read more about settlement)
Post tension slabs
Newer homes with post tension slabs that were not installed properly; especially if the slabs’ post tension cables were not tensioned or pulled in a timely manner and the framing contractor got onto the slab too soon with heavy equipment and stacks of heavy lumber. In new construction framing contractors often are pushed or rush into the start of framing before the slab cables have been tightened, thus slab and flooring issues develop. (Learn more about Post Tension slabs)
It is just not older homes that have creaking floors, but newer homes likewise may have creaking floors.
Creaking sounds may come from the subfloor or from the wood flooring itself. At times, some floors appear to amplify creaking sounds and make them sound much worse than they really are.
Generally, creaking floors are not caused by settling or soil movement, however you may want to check your foundation for cracks or other problems.