ᐅ Warping of Wooden Staircases and Cracks in Wood

Hello everyone!

We moved into our new build in November last year after a relatively short construction period of 7 months.
We had a concrete staircase installed with wooden treads, as well as wood cladding on the balustrade. It is parquet-glued beech with a lacquer finish.

Now, after less than 8 months, both the treads and the balustrade have warped significantly. The outer edges of the wood are lifting upwards, causing the silicone joints to crack and, in some cases, the glue in the middle of the wood panels to come loose. The difference between the edges and the center has now reached over 6mm (0.24 inches).

The indoor humidity level is actually not high, thanks to regular ventilation and consistent heating despite the fast construction time. There is a humidity sensor installed near the staircase that almost never shows more than 60%. The room temperature is kept constant by underfloor heating. During April and May, we experienced a dry period with humidity around 30% for several weeks. Could this be due to too rapid drying caused by the ventilation, leading the wood surface to contract? Has anyone experienced something similar?

At first, I did not worry about the silicone joints cracking because wood naturally expands and contracts. However, we have now noticed cracks in the wood itself, and it is clearly lifting at the edges.

I would appreciate any input!
Best regards,
CW

bau_clem schrieb:

However, we have now noticed the cracks in the wood in the middle.

That’s not a crack!? It looks like a scratch!

Unfortunately not. The glue bond at the top and right side is also coming loose, causing a triangular shape to lift up and stand above the rest of the board – it’s not clearly visible in the photo.

It is the responsibility of the staircase builder to verify whether the staircase and the entire structure have dried sufficiently.

In my opinion, the cause is that the wood absorbed moisture at the contact surface with the concrete or adhesive. This inevitably leads to warping. At that point, it can no longer be prevented. I believe this should improve over time.

Whether the wood was sufficiently dry during production can no longer be verified.

After 7 months, your house is still soaking wet, and 60% humidity at around 24°C (75°F) or higher is no small matter; this also affects parquet flooring and other types of wood. It was probably too early to cover the staircase with wood.