Raised Flagstone Patio

[Kendra]

Are foundation requirements the same for exterior patios/porches and things like ADA walkways as they are for adjacent buildings? I am doing a patio outside a commmercial property that is 18" off the ground and am less familiar with hardscape design. Thank you in advance!

 

[classicT]

They do not typically require foundations if built directly upon grade.

 

[steveray]

They do not typically require foundations if built directly upon grade.

AND not attached to a frost protected structure.....I know there has been some debate on this for exterior landings, but have never seen a frost protected patio....Porch probably, ramp probably, sidewalk/ patio not likely...,

 

[ADAguy]

Check soil for expansive characteristics or not

 

[Paul Sweet]

There should be at least 4", preferably 8", of crushed stone to allow any frost to expand into the spaces between the stones and not heave the patio, if the patio is at the same level as the inside floor.