When and How to Power Trowel Concrete? Practical Guide with the Boot Test and Tips

A smooth and durable concrete floor starts with precisely executed troweling. This key stage determines not only the appearance but also the longevity of the surface. In this guide, we explain when to start troweling concrete, how weather affects setting time, and why it’s important to perform the so-called boot test. You’ll also learn why troweling the next day is a bad idea and how to care for concrete after finishing.

What is concrete troweling and why is it so important?

Concrete troweling is the process of mechanically or manually smoothing the surface of fresh concrete. The goal is to achieve a level, dense, and wear-resistant surface layer. Properly performed troweling:

• improves abrasion resistance,
• closes surface pores and limits moisture or liquid penetration,
• enhances aesthetics and facilitates further work (e.g. sealing, painting),
• reduces dusting.

When to trowel concrete? Know the perfect moment!

The best time to start troweling is when the concrete is no longer liquid but still slightly plastic. Professionals use the so-called boot test – if stepping gently leaves an imprint about 2–4 mm deep, you can start troweling with a float.

Does concrete class affect troweling time?

Concrete classes like B20 (C16/20) or B25 (C20/25) define strength after 28 days. The initial setting time is usually similar but can vary due to:

• cement content,
• chemical additives (plasticizers),
• weather conditions (temperature, wind).

Always perform the boot test – it’s the most reliable method. Regardless of concrete class, proper curing after troweling is essential.

Can you trowel concrete the next day?

No. Troweling must be done the same day. After several hours, concrete gets too hard – the power trowel won’t smooth the surface and may cause damage.

If you missed the right moment, the only option might be concrete grinding after full curing – a costly and labor-intensive process.

How does weather affect concrete troweling?

Rain? Avoid troweling during rain – drops can wash out cement. If it starts raining, immediately cover the surface with plastic sheeting.

Post-troweling concrete care – key to durability

After troweling, concrete needs to cure. This means keeping it moist and protected for the next several days.

• Cut joints as soon as possible (reduces stress and prevents cracking).