ᐅ Patio without slope – According to which standard or regulation?
Created on: 26 Aug 2025 18:45
H
HausbauFrage
Hello!
Our outdoor area, including the terrace, was recently installed by a landscaper. Since our house is a timber frame construction, a base channel was installed between the house and the ground-level terrace. It is an Aco Profi Line with a width of 25cm (10 inches) and a height of 30cm (12 inches), which drains through the side slots into the gravel bed. The terrace consists of concrete slabs laid on a layer of gravel. The joints were filled with joint mortar, so no significant drainage through the terrace joints is expected.
Now we have noticed that the terrace has no slope...
What could be the worst-case scenario, and are there any measures that could be taken without completely relaying the terrace?
I see the risk that during heavy rain, a large portion of the water will flow toward the house, and the base channel might not drain the water fast enough through the drainage slots.
Also, I have read about algae growth. Does this actually occur in practice?
Which DIN standard or other regulation specifically states that a slope away from the house is part of the recognized rules of technology?
Our outdoor area, including the terrace, was recently installed by a landscaper. Since our house is a timber frame construction, a base channel was installed between the house and the ground-level terrace. It is an Aco Profi Line with a width of 25cm (10 inches) and a height of 30cm (12 inches), which drains through the side slots into the gravel bed. The terrace consists of concrete slabs laid on a layer of gravel. The joints were filled with joint mortar, so no significant drainage through the terrace joints is expected.
Now we have noticed that the terrace has no slope...
What could be the worst-case scenario, and are there any measures that could be taken without completely relaying the terrace?
I see the risk that during heavy rain, a large portion of the water will flow toward the house, and the base channel might not drain the water fast enough through the drainage slots.
Also, I have read about algae growth. Does this actually occur in practice?
Which DIN standard or other regulation specifically states that a slope away from the house is part of the recognized rules of technology?
N
nordanney28 Aug 2025 23:07Regarding the question of where the slope requirements are specifically described:
As far as I know, there are no concrete, binding regulations for terraces (similar to DIN or equivalent standards). However, incorporating a slope is considered good engineering practice. The guidelines refer to the DIN standards for (flat) roofs, which specify a slope of 2% as well as the official technical rules from the roofing trade and the Central Association of the German Construction Industry, which also recommend 2%.
For stone terraces laid on crushed stone or similar materials, I agree that a slope is essential. For elevated terraces (i.e., stone terraces on pedestals or wooden decks), I would never incorporate a slope because only a minimal amount of water tends to remain there, and approximately 98% is drained through the joints and the underlying structure (based on my own experience with numerous terraces and feedback from terrace builders).
As far as I know, there are no concrete, binding regulations for terraces (similar to DIN or equivalent standards). However, incorporating a slope is considered good engineering practice. The guidelines refer to the DIN standards for (flat) roofs, which specify a slope of 2% as well as the official technical rules from the roofing trade and the Central Association of the German Construction Industry, which also recommend 2%.
For stone terraces laid on crushed stone or similar materials, I agree that a slope is essential. For elevated terraces (i.e., stone terraces on pedestals or wooden decks), I would never incorporate a slope because only a minimal amount of water tends to remain there, and approximately 98% is drained through the joints and the underlying structure (based on my own experience with numerous terraces and feedback from terrace builders).
@HausbauFrage I think you can interpret the individual feedback according to the intentions of each author, and of course, no one wants to deny you anything or pressure you. However, reacting with reflexive shouting is not a helpful trait during construction.
@MachsSelbst I read that you wanted to sell your flawless house, which you never like to show, and that you already said goodbye here. Maybe try dialing down your tone by a couple of notches—more in line with your reality.
@MachsSelbst I read that you wanted to sell your flawless house, which you never like to show, and that you already said goodbye here. Maybe try dialing down your tone by a couple of notches—more in line with your reality.
Arauki11 schrieb:
At least that’s what I read from you, and you had already said goodbye here, so try dialing down your tone by two notches—matching your reality. No, that was the woman who was having difficulties. Or was it both, that suffer from his tone? A forum pulls out its popcorn supply, but what about the surrounding environment?
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