ᐅ Terrace construction: aluminum rails supported by building protection mats

Hello everyone,

We are currently having our terrace constructed, and I have a quick question about the build-up.

The landscaper prepared the base and finally installed edging or border stones about 8 cm (3 inches) high, which are placed on a weed control fabric.

Now the carpenter, who is supposed to finish the terrace, was here. Today he laid his aluminum substructure directly on the edging stones – however, the substructure is not resting directly on them; instead, it is supported by construction protection mats of varying thicknesses. In almost every spot, more or fewer mats were used to level it out.

This seems a bit improvised to me. Shouldn't the landscaper have already precisely prepared the correct heights and slope during the base construction?

So my question is:
Is this a common and acceptable practice, or is it more like poor workmanship or a temporary solution that is better to avoid?

Thank you in advance for your opinions and experiences!

harkonsen schrieb:

That seems a bit adventurous to me. Shouldn't the gardener actually prepare the correct heights and the slope precisely during the substructure work?

He will never get it that precise.

It could have been done nicer, but it is functional and perfectly fine (as long as the structure is properly aligned).

Wood or WPC? I hope the deck is level without any slope. That’s usually not necessary, except with WPC where the joints are completely closed.

The terrace will be laid with bamboo decking boards. As far as I understand, the aluminum rails currently have a 2% slope away from the house. That should be correct, right?

harkonsen schrieb:

As far as I understand, the aluminum rails now have a 2% slope away from the house. Shouldn’t they?

What do you need the slope for? So that rainwater might run a few seconds faster through the gap between the deck boards? The water will be drained below the deck anyway. With this kind of construction, there is always the argument like “but then water will stand on the boards,” which is not entirely wrong, but negligible.

I have been building my own decks this way without any slope for 20 years. So I have some experience (about 200 sq m (2150 sq ft) by now). The last one was just a few weeks ago.

Bamboo planks are slightly wider, so a 2% slope is justified.

Bamboo looks elegant right after installation, but I find it becomes dull after a short time.

Using a building protection mat for leveling is fine. You barely notice it later over the surface.

Singelküche schrieb:

Bamboo planks are a bit wider, so a 2% slope is justified.

I don’t understand…

Whether they are 11.5cm (4.5 inches), 13.7cm (5.4 inches), or 14.5cm (5.7 inches) wide makes no difference at all.