[PSUscaper]

I'm not positive, but what I think you are planning to do is just bury the concrete pad underneath the new patio, which will cover a area larger than the pad.

If this is the case, I would plan on removing it.

Have you ever driven down a highway that was a ovelay of asphalt over a old exis concrete road? If you have, then you see what happens. Where the new aphalt/base material extends past the concrete, you get a heave. Also, where ever there was a expansion joint in the the concrete, you get a heave.

This is a 12' x 12' pad........hardly a big job to remove. If you look at the long term risk of the pad heaving up the bricks above it and the cost of repairing it, it should easily out weigh the cost of removing the pad. If this is a budget conscious customer who is concerned about cost, then leave it....but get him to sign off on the consequences. If you believe in doing a quality job, and your customer is paying you to do so, take it out.

I would take it out without thinking twice. I also have to ask why removal is not possible? This sounds like a decent size job. Are you telling me that removing a 12 x 12 concrete pad (about 3 yards of concrete if 6" thick) is going to break the budget? That you don't have a machine capable of doing it? That you can't rent a jackhammer for the day?

I have to say, that hearing this, makes me a little nervous on the rest of the project. If this question were on the homeowner forum, I may be a little bit more willing to understand that its a lot more work to take out and that it may only cause slight problems....but this is a place for professionals, and hopefully, you will listen to the advice given, as it has be gained through years of experience.