Question
Hi
I have build a patio on the backyard and in this process the Bermuda grass is destroyed . We are planing to lay new sod but the lawn care company has applied pre and post emergent with slow fertilizer  on the rest of the yard and also around patio where there was dead grass and sand . How soon can I lay sod so this chemicals don't interfere with the rooting of sod. Please advice .

Answer
The short answer is, "Ask the Company who put down the products."
The long answer is that all chemicals - even the individual chemicals in the group 'Pre-emergent' - have a particular mode of action. (MOA). They have a residual effect (long or short term). Most, if not all, States have a "Right to Know Law" which requires Service Companies to let you know what chemicals are used on your property. Therefore, ask! If they give you names or terms that are unfamiliar, seek out further information on the internet or from the nearest Extension Office.