If the concrete slab is not flat but dips in places or has a hump, then the flooring laid on top of the slab may bow or be spongy when stepping on the areas that dips or does not have a fully flat surface. Laminate flooring is susceptible to this and may even make a creaking of snapping sound when stepped on.
A spongy feel underfoot might indicate that the subfloor is not securely attached to the floor joists. This condition allows the floor to give slightly when you step.
Why does your laminate flooring feel spongy? A laminate floor that feels spongy can be caused by any of these 5 conditions: an uneven sub-floor, an underlayment issue, an expansion gap issue, water damage, or termite damage.
Bouncy floors are a common phenomenon in homes, according to This Old House's general contractor Tom Silva. Also known as spongy floors, this problem occurs in new and old homes alike. "Even structurally sound, code-compliant new floors can deflect, or flex, more than feels comfortable," per This Old House.
Floor vibrations are generally related to human activity, vibrating machinery and external forces. Walking is the most common source of floor vibrations and more than anything is simply considered a nuisance.
Fix bouncy floors by adding bridging, adding a layer of plywood or adding a wall or beam. We'll show you three ways to stiffen up your bouncy floor—by adding bridging, installing plywood along the joists and adding a wall or beam under the floor. Any one of the three can solve your problem, depending on your situation.
Spongy and bouncy floors generally are of little concern unless the cause relates to a serious structural issue. As homeowners we quickly get used to a floor that has a little bouncy or spring to it as we walk across it and seldom give any thought to whether there is a problem.
If there are no visible signs of mould on the walls and the carpet isn't the culprit, you could be dealing with rot inside your floor. Creaky floorboards are a tell-tale sign that joists and floorboards are damaged or decaying.
LVT, Laminate or Wood Floor Bouncing
When weight is applied to the flooring, it moves downward because it is not supported, causing the bounce. This will put pressure on the flooring joints and will often cause them to squeek, break and even separate.
Foam Away Spongy Spots. Soft spots in a laminate floor can be caused by an uneven sub-floor or improper installation of flooring underlayment. For quick repairs of soft spots in your laminate floor use an air inflation needle or a syringe (used to blow up sports balls) on a can of spray foam.
However, a common issue in laminate flooring is a spongy feeling to the floor or having what feels like soft spots in the floor that feel bouncy as you walk over them.
One of the main reasons why floating floors like laminate may bounce is because of temperature and moisture issues. If there are water or roof leaks in the room where the laminate flooring was installed, make sure to solve it immediately before it causes more damage to the floors or the home.
Your floorboards squeak – loudly.
As you walk across the floor, the nails move in and out of the wooden joists, causing the awful, familiar sound of creaky floorboards. If you notice squeaking throughout the entire room, this could be a sign that the material has warped.
If the joists or columns are spaced too far apart, the joists will sag and bounce. Home remodeling projects, such as adding an addition, installing new appliances, granite countertops or large furniture pieces can add extra weight and stress to the floor joists– leading to bouncy floors. Don't take short cuts!
A: Sagging floors are more common than you might think. In my opinion, the most common causes are wood-eating insects, wood rot caused by water leaks, undersized beams and soil settlement.
Moisture. The most telling indication that a squeaky and lumpy floor may be rotting is the presence of moisture. Moisture may not be apparent on the surface, especially if the floor covering is hardwood, but you may see indications of it from underneath.
However common characteristics of a typical dry rot smell include: Earthy odour. Mushroom-like smell. Musty and damp smell.
Underlayment
The underlayment material is installed below the floor covering and placed on top of a subfloor. Under the visible covering, there is a layer made of soft or foam-like materials with a thickness of between 1/4 – 1/2-inch.
A floor collapse injury can occur at a construction site if the floor is made heavier than the support beams that hold it up. Many floor collapses occur when workers begin to pour the concrete that forms the floor.
Water damage from storms, plumbing leaks or roof leaks, especially over time may create wood rot, damage and deterioration. Pests, such as termites, also causes wood deterioration and can weaken the strongest of beams, post and joist, creating sagging and sloping floors.
Poor structural support is the most common cause of sagging floors. When your floor joists start to bend downwards due to pressure and weight of the overlying material, your floor will start sagging. The best way to fix sagging floor joists is by installing new support structures such as jacks.
If the attic joists are not adequate, one way to strengthen the floor for live loads is to sister the old joists. Sistering is the process of adding a new joist next to each existing joist. In the case of 2 x 6 joists, you can pair them up with additional 2 x 6 joists by nailing them together, side by side.
The solution to sagging floors, or the damaged sills and joist ends that contribute to them, often involves jacking. A common scenario is to install temporary jack posts and support beams, then permanent posts and beams over new footings.