ᐅ Foundation for a 3x3 meter pergola

Hello,

I am a bit uncertain about the foundation for a 3x3 meter (10x10 feet) pergola. We have a terrace with floating but very firmly fixed concrete pavers (about 4 cm (1.5 inches) thick). Setting aside all general recommendations for a moment, would you still insist on building a foundation of 30 cm x 30 cm x 40 cm (12 x 12 x 16 inches), or do you think the pergola could also be stable directly on the pavers? Alternatively, we are considering removing the affected pavers, excavating the gravel base, pouring a 10–15 cm (4–6 inches) thick cement mortar layer, laying the pavers into the mortar bed, and then anchoring the pergola into this new slab. The pergola is generally well protected from the wind and located close to the house. It will be made of powder-coated aluminum, so it is quite heavy.

Thanks for your advice and best regards

Is it really a pergola, meaning without a roof, basically just rafters? In that case, I would probably build it that way as well. If a roof is planned in the medium term, I would definitely create proper foundations, at a depth of 80cm (31 inches).

Whether an 80cm (31.5 inches) foundation is necessary can be debated, but 10-15cm (4-6 inches) as a base layer is definitely not sufficient. The anchors should then go through the slab into the foundation.

Tolentino schrieb:

Is it really a pergola, meaning without a roof, basically just rafters? If so, I would probably build it that way too.
If a roof covering is planned in the medium term, I would make proper foundations, but 80cm (31 inches) deep.

Ah, I forgot to mention. It will have a louvered roof.

Then make a proper pier foundation

Yes, proper foundations are needed with a roof. The suction forces that act on it during a minor storm are incredible. Axel Earlier this year, a pavilion was torn down by winds with gusts up to 79 km/h (49 mph). That is actually not much at all.