ᐅ Which screws are suitable for heavy loads?

I have a technical question that I would like to discuss here: Which screws are particularly suitable for heavy loads? I am especially interested in their use in steel and timber construction, where the screws not only need to withstand high forces but also remain reliable over the long term. Which types and materials are recommended? Are there specific standards to consider or particular screw head designs that should be chosen? It would be great if you could share well-proven solutions from your experience, as well as tips for selection and installation.

That’s a really interesting question! Especially with heavy loads, I can understand how important it is to choose the right screw to ensure nothing gives way later or becomes dangerous. I remember when I was building a carport, I only looked at the price and ended up with screws that were prone to rust, which caused problems later on. From personal experience, I can confirm that stainless steel or galvanized screws are very important for moisture resistance.

BENFIKRET schrieb:
Which types and materials are recommended? Do you have to pay attention to specific standards or choose certain screw head types?

I would also recommend standards like DIN EN 14399 for high-strength bolts, which are often used in steel structures. For wood, there are special high-tensile screws that grip better.

For heavy loads, always use screws made of high-strength steel (e.g., grade 8.8 or higher). Stainless steel is corrosion-resistant but not always as strong. Follow standards, for example ISO 898-1.

As a supplement: For heavy loads in steel construction, fasteners with a property class of 10.9 or higher are recommended, as they provide high tensile and shear strength. Additionally, using partially threaded bolts is advisable because the unthreaded shank acts as a pin and can bear higher loads. In timber construction, specially engineered structural wood screws with large diameters (8mm (0.3 inches) and above) are well suited.

Timmyse36 schrieb:
For wood, there are special high-tensile screws

These are exactly the screws that provide high withdrawal and tensile strength.

Important: Screws must always be sized according to the requirements and installed correctly by a professional.

Oh, this is great that so much information is coming together here! 🙂 I just want to add that when it comes to screws for heavy loads, it’s really important to pay attention to the coating, especially if the screw will be used outdoors. Galvanized or stainless steel screws prevent rust and ensure a long service life! And if you want to be really serious, you might also consider locking elements to prevent the screws from loosening. A solid connection like that really makes a difference! :-)

For heavy loads, the screw length should not be underestimated. A screw should always be at least 2.5 to 3 times as long as its diameter to provide sufficient holding power. Also, make sure to use the appropriate pilot hole size to avoid splitting the wood or weakening the steel.