Reducing foundation costs

I'll keep my mental clothes on, thanks

 

Prude

 

Galvanising? Red oxide primer? They're good enough for bi-fold lintels which are also exposed.

 

Well yes exactly!

 

That's a useful picture, thanks. So in your case a 203x20x46 is sufficient for a 4.5m span. Is it domestic? What's it carrying?

 

Galvanising has a significant cost. Red oxide is not a protective coat.

In any case the ground, or the sub-floor void is a completely different location in terms of damp and ventilation

 

And anyway, negligence isn't governed by contract. It's why we have (and can have) PI.