Will three load-bearing beams be enough?

[Byggglädje]

Hello

800mm sounds like quite a lot, there is surely someone who can calculate the deflection. Not me though.
I would have put a row of concrete slabs above the service line.
(Or I wouldn't have done that or built a decking that covers it if I needed to access it. It's also boring to dismantle the decking. Consider if you really need to have decking there).

 

[Stefan1972]

Do you have to have footings then? From a layman's perspective, everything sounds very rough and oversized. I have a similarly sized piece and it's on slabs and made of relatively light timber compared to standards. Just cheap thin decking too. I don't experience any issues with it. What does it matter if it flexes a few millimeters?

 

[JF.]

Do you really need to have foundations then? From a layman's perspective, everything sounds very rough and exaggerated. I have a similarly sized piece and it's laid on slabs and made of fairly light timber compared to the norms. Just cheap thin decking as well. I don't experience any issues with it. What does it matter if it flexes a few millimeters, for example?

I would have liked to avoid foundations, but the ground is at different levels, hence the foundations. I've made a simple little sketch from the side.

 

[Stefan1972]

Screwed posts in well-chosen spots and then plates at the bottom should work, right? Then you have something to screw into if you want to clad underneath with boards too.....

 

[JF.]

Screwed posts in well-chosen spots and then plates at the bottom should work, right? Then you have something to screw into if you want to board underneath as well.....

Concrete slabs on the far left with supports I also think will be good. It is at least the easiest way.

 

[Darling McFluff]

My terrace is a combination of foundations and slabs

 

[JF.]

My terrace is a combination of pilasters and tiles

Satisfied with the result?

 

[MultiMan]

I have extreme frost heave and ground movements, so the day I build a deck, I must either replace the material on that entire side of the property or use only deep pilings; otherwise, the deck would be broken apart by the ground's movements.

So make sure to check this before deciding which method to use.

 

[Darling McFluff]

Satisfied with the result?

Absolutely, against the house it's against the foundation. Outermost with a post and in the middle on slabs.

You can't dig endlessly